| /* |
| * Copyright (c) 2008-2013 Apple Inc. All rights reserved. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_START@ |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| * @APPLE_APACHE_LICENSE_HEADER_END@ |
| */ |
| |
| #include "internal.h" |
| #if HAVE_MACH |
| #include "protocol.h" // _dispatch_send_wakeup_runloop_thread |
| #endif |
| |
| #if HAVE_PTHREAD_WORKQUEUES || DISPATCH_USE_INTERNAL_WORKQUEUE |
| #define DISPATCH_USE_WORKQUEUES 1 |
| #endif |
| #if (!HAVE_PTHREAD_WORKQUEUES || DISPATCH_DEBUG) && \ |
| !defined(DISPATCH_ENABLE_THREAD_POOL) |
| #define DISPATCH_ENABLE_THREAD_POOL 1 |
| #endif |
| #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES || DISPATCH_ENABLE_THREAD_POOL |
| #define DISPATCH_USE_PTHREAD_POOL 1 |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUES && (!HAVE_PTHREAD_WORKQUEUE_QOS || \ |
| DISPATCH_DEBUG) && !HAVE_PTHREAD_WORKQUEUE_SETDISPATCH_NP && \ |
| !defined(DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK) |
| #define DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK 1 |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUE_SETDISPATCH_NP && (DISPATCH_DEBUG || \ |
| (!DISPATCH_USE_KEVENT_WORKQUEUE && !HAVE_PTHREAD_WORKQUEUE_QOS)) && \ |
| !defined(DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP) |
| #define DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP 1 |
| #endif |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP || \ |
| DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK || \ |
| DISPATCH_USE_INTERNAL_WORKQUEUE |
| #if !DISPATCH_USE_INTERNAL_WORKQUEUE |
| #define DISPATCH_USE_WORKQ_PRIORITY 1 |
| #endif |
| #define DISPATCH_USE_WORKQ_OPTIONS 1 |
| #endif |
| |
| #if DISPATCH_USE_WORKQUEUES && DISPATCH_USE_PTHREAD_POOL && \ |
| !DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| #define pthread_workqueue_t void* |
| #endif |
| |
| static void _dispatch_sig_thread(void *ctxt); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_cache_cleanup(void *value); |
| static void _dispatch_async_f2(dispatch_queue_t dq, dispatch_continuation_t dc); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_queue_cleanup(void *ctxt); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_wlh_cleanup(void *ctxt); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_deferred_items_cleanup(void *ctxt); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_frame_cleanup(void *ctxt); |
| static void DISPATCH_TSD_DTOR_CC _dispatch_context_cleanup(void *ctxt); |
| static void _dispatch_queue_barrier_complete(dispatch_queue_t dq, |
| dispatch_qos_t qos, dispatch_wakeup_flags_t flags); |
| static void _dispatch_queue_non_barrier_complete(dispatch_queue_t dq); |
| static void _dispatch_queue_push_sync_waiter(dispatch_queue_t dq, |
| dispatch_sync_context_t dsc, dispatch_qos_t qos); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| static void _dispatch_root_queue_push_override_stealer(dispatch_queue_t orig_rq, |
| dispatch_queue_t dq, dispatch_qos_t qos); |
| static inline void _dispatch_queue_class_wakeup_with_override(dispatch_queue_t, |
| uint64_t dq_state, dispatch_wakeup_flags_t flags); |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUES |
| static void _dispatch_worker_thread4(void *context); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| static void _dispatch_worker_thread3(pthread_priority_t priority); |
| #endif |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| static void _dispatch_worker_thread2(int priority, int options, void *context); |
| #endif |
| #endif |
| #if DISPATCH_USE_PTHREAD_POOL |
| static void *_dispatch_worker_thread(void *context); |
| #if defined(_WIN32) |
| static unsigned WINAPI |
| _dispatch_worker_thread_thunk(LPVOID lpParameter); |
| #endif |
| #endif |
| |
| #if DISPATCH_COCOA_COMPAT |
| static dispatch_once_t _dispatch_main_q_handle_pred; |
| static void _dispatch_runloop_queue_poke(dispatch_queue_t dq, |
| dispatch_qos_t qos, dispatch_wakeup_flags_t flags); |
| static void _dispatch_runloop_queue_handle_init(void *ctxt); |
| static void _dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq); |
| #endif |
| |
| #pragma mark - |
| #pragma mark dispatch_root_queue |
| |
| struct dispatch_pthread_root_queue_context_s { |
| #if !defined(_WIN32) |
| pthread_attr_t dpq_thread_attr; |
| #endif |
| dispatch_block_t dpq_thread_configure; |
| struct dispatch_semaphore_s dpq_thread_mediator; |
| dispatch_pthread_root_queue_observer_hooks_s dpq_observer_hooks; |
| }; |
| typedef struct dispatch_pthread_root_queue_context_s * |
| dispatch_pthread_root_queue_context_t; |
| |
| #if DISPATCH_ENABLE_THREAD_POOL |
| static struct dispatch_pthread_root_queue_context_s |
| _dispatch_pthread_root_queue_contexts[] = { |
| [DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS_OVERCOMMIT] = { |
| .dpq_thread_mediator = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(semaphore), |
| }}, |
| }; |
| #endif |
| |
| #ifndef DISPATCH_WORKQ_MAX_PTHREAD_COUNT |
| #define DISPATCH_WORKQ_MAX_PTHREAD_COUNT 255 |
| #endif |
| |
| struct dispatch_root_queue_context_s { |
| union { |
| struct { |
| int volatile dgq_pending; |
| #if DISPATCH_USE_WORKQUEUES |
| qos_class_t dgq_qos; |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| int dgq_wq_priority; |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| int dgq_wq_options; |
| #endif |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK || DISPATCH_USE_PTHREAD_POOL |
| pthread_workqueue_t dgq_kworkqueue; |
| #endif |
| #endif // DISPATCH_USE_WORKQUEUES |
| #if DISPATCH_USE_PTHREAD_POOL |
| void *dgq_ctxt; |
| int32_t volatile dgq_thread_pool_size; |
| #endif |
| }; |
| char _dgq_pad[DISPATCH_CACHELINE_SIZE]; |
| }; |
| }; |
| typedef struct dispatch_root_queue_context_s *dispatch_root_queue_context_t; |
| |
| #define WORKQ_PRIO_INVALID (-1) |
| #ifndef WORKQ_BG_PRIOQUEUE_CONDITIONAL |
| #define WORKQ_BG_PRIOQUEUE_CONDITIONAL WORKQ_PRIO_INVALID |
| #endif |
| #ifndef WORKQ_HIGH_PRIOQUEUE_CONDITIONAL |
| #define WORKQ_HIGH_PRIOQUEUE_CONDITIONAL WORKQ_PRIO_INVALID |
| #endif |
| |
| DISPATCH_CACHELINE_ALIGN |
| static struct dispatch_root_queue_context_s _dispatch_root_queue_contexts[] = { |
| [DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_MAINTENANCE, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_BG_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_MAINTENANCE, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_BG_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_MAINTENANCE_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_BACKGROUND, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_BG_PRIOQUEUE_CONDITIONAL, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_BACKGROUND, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_BG_PRIOQUEUE_CONDITIONAL, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_UTILITY, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_LOW_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_UTILITY, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_LOW_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_DEFAULT, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_DEFAULT_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_DEFAULT, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_DEFAULT_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_USER_INITIATED, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_HIGH_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_USER_INITIATED, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_HIGH_PRIOQUEUE, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_USER_INTERACTIVE, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_HIGH_PRIOQUEUE_CONDITIONAL, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = 0, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS], |
| #endif |
| }}}, |
| [DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS_OVERCOMMIT] = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_qos = QOS_CLASS_USER_INTERACTIVE, |
| #if DISPATCH_USE_WORKQ_PRIORITY |
| .dgq_wq_priority = WORKQ_HIGH_PRIOQUEUE_CONDITIONAL, |
| #endif |
| #if DISPATCH_USE_WORKQ_OPTIONS |
| .dgq_wq_options = WORKQ_ADDTHREADS_OPTION_OVERCOMMIT, |
| #endif |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| .dgq_ctxt = &_dispatch_pthread_root_queue_contexts[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS_OVERCOMMIT], |
| #endif |
| }}}, |
| }; |
| |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| DISPATCH_CACHELINE_ALIGN |
| struct dispatch_queue_s _dispatch_root_queues[] = { |
| #define _DISPATCH_ROOT_QUEUE_IDX(n, flags) \ |
| ((flags & DISPATCH_PRIORITY_FLAG_OVERCOMMIT) ? \ |
| DISPATCH_ROOT_QUEUE_IDX_##n##_QOS_OVERCOMMIT : \ |
| DISPATCH_ROOT_QUEUE_IDX_##n##_QOS) |
| #define _DISPATCH_ROOT_QUEUE_ENTRY(n, flags, ...) \ |
| [_DISPATCH_ROOT_QUEUE_IDX(n, flags)] = { \ |
| DISPATCH_GLOBAL_OBJECT_HEADER(queue_root), \ |
| .dq_state = DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE, \ |
| .do_ctxt = &_dispatch_root_queue_contexts[ \ |
| _DISPATCH_ROOT_QUEUE_IDX(n, flags)], \ |
| .dq_atomic_flags = DQF_WIDTH(DISPATCH_QUEUE_WIDTH_POOL), \ |
| .dq_priority = _dispatch_priority_make(DISPATCH_QOS_##n, 0) | flags | \ |
| DISPATCH_PRIORITY_FLAG_ROOTQUEUE | \ |
| ((flags & DISPATCH_PRIORITY_FLAG_DEFAULTQUEUE) ? 0 : \ |
| DISPATCH_QOS_##n << DISPATCH_PRIORITY_OVERRIDE_SHIFT), \ |
| __VA_ARGS__ \ |
| } |
| _DISPATCH_ROOT_QUEUE_ENTRY(MAINTENANCE, 0, |
| .dq_label = "com.apple.root.maintenance-qos", |
| .dq_serialnum = 4, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(MAINTENANCE, DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.maintenance-qos.overcommit", |
| .dq_serialnum = 5, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(BACKGROUND, 0, |
| .dq_label = "com.apple.root.background-qos", |
| .dq_serialnum = 6, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(BACKGROUND, DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.background-qos.overcommit", |
| .dq_serialnum = 7, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(UTILITY, 0, |
| .dq_label = "com.apple.root.utility-qos", |
| .dq_serialnum = 8, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(UTILITY, DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.utility-qos.overcommit", |
| .dq_serialnum = 9, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(DEFAULT, DISPATCH_PRIORITY_FLAG_DEFAULTQUEUE, |
| .dq_label = "com.apple.root.default-qos", |
| .dq_serialnum = 10, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(DEFAULT, |
| DISPATCH_PRIORITY_FLAG_DEFAULTQUEUE | DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.default-qos.overcommit", |
| .dq_serialnum = 11, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(USER_INITIATED, 0, |
| .dq_label = "com.apple.root.user-initiated-qos", |
| .dq_serialnum = 12, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(USER_INITIATED, DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.user-initiated-qos.overcommit", |
| .dq_serialnum = 13, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(USER_INTERACTIVE, 0, |
| .dq_label = "com.apple.root.user-interactive-qos", |
| .dq_serialnum = 14, |
| ), |
| _DISPATCH_ROOT_QUEUE_ENTRY(USER_INTERACTIVE, DISPATCH_PRIORITY_FLAG_OVERCOMMIT, |
| .dq_label = "com.apple.root.user-interactive-qos.overcommit", |
| .dq_serialnum = 15, |
| ), |
| }; |
| |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| static const dispatch_queue_t _dispatch_wq2root_queues[][2] = { |
| [WORKQ_BG_PRIOQUEUE][0] = &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS], |
| [WORKQ_BG_PRIOQUEUE][WORKQ_ADDTHREADS_OPTION_OVERCOMMIT] = |
| &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_BACKGROUND_QOS_OVERCOMMIT], |
| [WORKQ_LOW_PRIOQUEUE][0] = &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS], |
| [WORKQ_LOW_PRIOQUEUE][WORKQ_ADDTHREADS_OPTION_OVERCOMMIT] = |
| &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_UTILITY_QOS_OVERCOMMIT], |
| [WORKQ_DEFAULT_PRIOQUEUE][0] = &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS], |
| [WORKQ_DEFAULT_PRIOQUEUE][WORKQ_ADDTHREADS_OPTION_OVERCOMMIT] = |
| &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT], |
| [WORKQ_HIGH_PRIOQUEUE][0] = &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS], |
| [WORKQ_HIGH_PRIOQUEUE][WORKQ_ADDTHREADS_OPTION_OVERCOMMIT] = |
| &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INITIATED_QOS_OVERCOMMIT], |
| }; |
| #endif // DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| static struct dispatch_queue_s _dispatch_mgr_root_queue; |
| #else |
| #define _dispatch_mgr_root_queue _dispatch_root_queues[\ |
| DISPATCH_ROOT_QUEUE_IDX_USER_INTERACTIVE_QOS_OVERCOMMIT] |
| #endif |
| |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| DISPATCH_CACHELINE_ALIGN |
| struct dispatch_queue_s _dispatch_mgr_q = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(queue_mgr), |
| .dq_state = DISPATCH_QUEUE_STATE_INIT_VALUE(1) | |
| DISPATCH_QUEUE_ROLE_BASE_ANON, |
| .do_targetq = &_dispatch_mgr_root_queue, |
| .dq_label = "com.apple.libdispatch-manager", |
| .dq_atomic_flags = DQF_WIDTH(1), |
| .dq_priority = DISPATCH_PRIORITY_FLAG_MANAGER | |
| DISPATCH_PRIORITY_SATURATED_OVERRIDE, |
| .dq_serialnum = 2, |
| }; |
| |
| dispatch_queue_t |
| dispatch_get_global_queue(long priority, unsigned long flags) |
| { |
| if (flags & ~(unsigned long)DISPATCH_QUEUE_OVERCOMMIT) { |
| return DISPATCH_BAD_INPUT; |
| } |
| dispatch_qos_t qos = _dispatch_qos_from_queue_priority(priority); |
| #if !HAVE_PTHREAD_WORKQUEUE_QOS |
| if (qos == QOS_CLASS_MAINTENANCE) { |
| qos = DISPATCH_QOS_BACKGROUND; |
| } else if (qos == QOS_CLASS_USER_INTERACTIVE) { |
| qos = DISPATCH_QOS_USER_INITIATED; |
| } |
| #endif |
| if (qos == DISPATCH_QOS_UNSPECIFIED) { |
| return DISPATCH_BAD_INPUT; |
| } |
| return _dispatch_get_root_queue(qos, flags & DISPATCH_QUEUE_OVERCOMMIT); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_queue_t |
| _dispatch_get_current_queue(void) |
| { |
| return _dispatch_queue_get_current() ?: |
| _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, true); |
| } |
| |
| dispatch_queue_t |
| dispatch_get_current_queue(void) |
| { |
| return _dispatch_get_current_queue(); |
| } |
| |
| DISPATCH_NOINLINE DISPATCH_NORETURN |
| static void |
| _dispatch_assert_queue_fail(dispatch_queue_t dq, bool expected) |
| { |
| _dispatch_client_assert_fail( |
| "Block was %sexpected to execute on queue [%s]", |
| expected ? "" : "not ", dq->dq_label ?: ""); |
| } |
| |
| DISPATCH_NOINLINE DISPATCH_NORETURN |
| static void |
| _dispatch_assert_queue_barrier_fail(dispatch_queue_t dq) |
| { |
| _dispatch_client_assert_fail( |
| "Block was expected to act as a barrier on queue [%s]", |
| dq->dq_label ?: ""); |
| } |
| |
| void |
| dispatch_assert_queue(dispatch_queue_t dq) |
| { |
| unsigned long metatype = dx_metatype(dq); |
| if (unlikely(metatype != _DISPATCH_QUEUE_TYPE)) { |
| DISPATCH_CLIENT_CRASH(metatype, "invalid queue passed to " |
| "dispatch_assert_queue()"); |
| } |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (likely(_dq_state_drain_locked_by_self(dq_state))) { |
| return; |
| } |
| // we can look at the width: if it is changing while we read it, |
| // it means that a barrier is running on `dq` concurrently, which |
| // proves that we're not on `dq`. Hence reading a stale '1' is ok. |
| // |
| // However if we can have thread bound queues, these mess with lock |
| // ownership and we always have to take the slowpath |
| if (likely(DISPATCH_COCOA_COMPAT || dq->dq_width > 1)) { |
| if (likely(_dispatch_thread_frame_find_queue(dq))) { |
| return; |
| } |
| } |
| _dispatch_assert_queue_fail(dq, true); |
| } |
| |
| void |
| dispatch_assert_queue_not(dispatch_queue_t dq) |
| { |
| unsigned long metatype = dx_metatype(dq); |
| if (unlikely(metatype != _DISPATCH_QUEUE_TYPE)) { |
| DISPATCH_CLIENT_CRASH(metatype, "invalid queue passed to " |
| "dispatch_assert_queue_not()"); |
| } |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (likely(!_dq_state_drain_locked_by_self(dq_state))) { |
| // we can look at the width: if it is changing while we read it, |
| // it means that a barrier is running on `dq` concurrently, which |
| // proves that we're not on `dq`. Hence reading a stale '1' is ok. |
| // |
| // However if we can have thread bound queues, these mess with lock |
| // ownership and we always have to take the slowpath |
| if (likely(!DISPATCH_COCOA_COMPAT && dq->dq_width == 1)) { |
| return; |
| } |
| if (likely(!_dispatch_thread_frame_find_queue(dq))) { |
| return; |
| } |
| } |
| _dispatch_assert_queue_fail(dq, false); |
| } |
| |
| void |
| dispatch_assert_queue_barrier(dispatch_queue_t dq) |
| { |
| dispatch_assert_queue(dq); |
| |
| if (likely(dq->dq_width == 1)) { |
| return; |
| } |
| |
| if (likely(dq->do_targetq)) { |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (likely(_dq_state_is_in_barrier(dq_state))) { |
| return; |
| } |
| } |
| |
| _dispatch_assert_queue_barrier_fail(dq); |
| } |
| |
| #if DISPATCH_DEBUG && DISPATCH_ROOT_QUEUE_DEBUG |
| #define _dispatch_root_queue_debug(...) _dispatch_debug(__VA_ARGS__) |
| #define _dispatch_debug_root_queue(...) dispatch_debug_queue(__VA_ARGS__) |
| #else |
| #define _dispatch_root_queue_debug(...) |
| #define _dispatch_debug_root_queue(...) |
| #endif |
| |
| #pragma mark - |
| #pragma mark dispatch_init |
| |
| static inline bool |
| _dispatch_root_queues_init_workq(int *wq_supported) |
| { |
| int r; (void)r; |
| bool result = false; |
| *wq_supported = 0; |
| #if DISPATCH_USE_WORKQUEUES |
| bool disable_wq = false; (void)disable_wq; |
| #if DISPATCH_ENABLE_THREAD_POOL && DISPATCH_DEBUG |
| disable_wq = slowpath(getenv("LIBDISPATCH_DISABLE_KWQ")); |
| #endif |
| #if DISPATCH_USE_KEVENT_WORKQUEUE || HAVE_PTHREAD_WORKQUEUE_QOS |
| bool disable_qos = false; |
| #if DISPATCH_DEBUG |
| disable_qos = slowpath(getenv("LIBDISPATCH_DISABLE_QOS")); |
| #endif |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| bool disable_kevent_wq = false; |
| #if DISPATCH_DEBUG || DISPATCH_PROFILE |
| disable_kevent_wq = slowpath(getenv("LIBDISPATCH_DISABLE_KEVENT_WQ")); |
| #endif |
| #endif |
| |
| if (!disable_wq && !disable_qos) { |
| *wq_supported = _pthread_workqueue_supported(); |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| if (!disable_kevent_wq && (*wq_supported & WORKQ_FEATURE_KEVENT)) { |
| r = _pthread_workqueue_init_with_kevent(_dispatch_worker_thread3, |
| (pthread_workqueue_function_kevent_t) |
| _dispatch_kevent_worker_thread, |
| offsetof(struct dispatch_queue_s, dq_serialnum), 0); |
| #if DISPATCH_USE_MGR_THREAD |
| _dispatch_kevent_workqueue_enabled = !r; |
| #endif |
| result = !r; |
| } else |
| #endif // DISPATCH_USE_KEVENT_WORKQUEUE |
| if (*wq_supported & WORKQ_FEATURE_FINEPRIO) { |
| #if DISPATCH_USE_MGR_THREAD |
| r = _pthread_workqueue_init(_dispatch_worker_thread3, |
| offsetof(struct dispatch_queue_s, dq_serialnum), 0); |
| result = !r; |
| #endif |
| } |
| if (!(*wq_supported & WORKQ_FEATURE_MAINTENANCE)) { |
| DISPATCH_INTERNAL_CRASH(*wq_supported, |
| "QoS Maintenance support required"); |
| } |
| } |
| #endif // DISPATCH_USE_KEVENT_WORKQUEUE || HAVE_PTHREAD_WORKQUEUE_QOS |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| if (!result && !disable_wq) { |
| pthread_workqueue_setdispatchoffset_np( |
| offsetof(struct dispatch_queue_s, dq_serialnum)); |
| r = pthread_workqueue_setdispatch_np(_dispatch_worker_thread2); |
| #if !DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| (void)dispatch_assume_zero(r); |
| #endif |
| result = !r; |
| } |
| #endif // DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK || DISPATCH_USE_PTHREAD_POOL |
| if (!result) { |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| pthread_workqueue_attr_t pwq_attr; |
| if (!disable_wq) { |
| r = pthread_workqueue_attr_init_np(&pwq_attr); |
| (void)dispatch_assume_zero(r); |
| } |
| #endif |
| size_t i; |
| for (i = 0; i < DISPATCH_ROOT_QUEUE_COUNT; i++) { |
| pthread_workqueue_t pwq = NULL; |
| dispatch_root_queue_context_t qc; |
| qc = &_dispatch_root_queue_contexts[i]; |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| if (!disable_wq && qc->dgq_wq_priority != WORKQ_PRIO_INVALID) { |
| r = pthread_workqueue_attr_setqueuepriority_np(&pwq_attr, |
| qc->dgq_wq_priority); |
| (void)dispatch_assume_zero(r); |
| r = pthread_workqueue_attr_setovercommit_np(&pwq_attr, |
| qc->dgq_wq_options & |
| WORKQ_ADDTHREADS_OPTION_OVERCOMMIT); |
| (void)dispatch_assume_zero(r); |
| r = pthread_workqueue_create_np(&pwq, &pwq_attr); |
| (void)dispatch_assume_zero(r); |
| result = result || dispatch_assume(pwq); |
| } |
| #endif // DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| if (pwq) { |
| qc->dgq_kworkqueue = pwq; |
| } else { |
| qc->dgq_kworkqueue = (void*)(~0ul); |
| // because the fastpath of _dispatch_global_queue_poke didn't |
| // know yet that we're using the internal pool implementation |
| // we have to undo its setting of dgq_pending |
| qc->dgq_pending = 0; |
| } |
| } |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| if (!disable_wq) { |
| r = pthread_workqueue_attr_destroy_np(&pwq_attr); |
| (void)dispatch_assume_zero(r); |
| } |
| #endif |
| } |
| #endif // DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK || DISPATCH_ENABLE_THREAD_POOL |
| #endif // DISPATCH_USE_WORKQUEUES |
| return result; |
| } |
| |
| #if DISPATCH_USE_PTHREAD_POOL |
| static inline void |
| _dispatch_root_queue_init_pthread_pool(dispatch_root_queue_context_t qc, |
| int32_t pool_size, bool overcommit) |
| { |
| dispatch_pthread_root_queue_context_t pqc = qc->dgq_ctxt; |
| int32_t thread_pool_size = overcommit ? DISPATCH_WORKQ_MAX_PTHREAD_COUNT : |
| (int32_t)dispatch_hw_config(active_cpus); |
| if (slowpath(pool_size) && pool_size < thread_pool_size) { |
| thread_pool_size = pool_size; |
| } |
| qc->dgq_thread_pool_size = thread_pool_size; |
| #if DISPATCH_USE_WORKQUEUES |
| if (qc->dgq_qos) { |
| #if !defined(_WIN32) |
| (void)dispatch_assume_zero(pthread_attr_init(&pqc->dpq_thread_attr)); |
| (void)dispatch_assume_zero(pthread_attr_setdetachstate( |
| &pqc->dpq_thread_attr, PTHREAD_CREATE_DETACHED)); |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| (void)dispatch_assume_zero(pthread_attr_set_qos_class_np( |
| &pqc->dpq_thread_attr, qc->dgq_qos, 0)); |
| #endif |
| } |
| #endif // HAVE_PTHREAD_WORKQUEUES |
| _dispatch_sema4_t *sema = &pqc->dpq_thread_mediator.dsema_sema; |
| _dispatch_sema4_init(sema, _DSEMA4_POLICY_LIFO); |
| _dispatch_sema4_create(sema, _DSEMA4_POLICY_LIFO); |
| } |
| #endif // DISPATCH_USE_PTHREAD_POOL |
| |
| static void |
| _dispatch_root_queues_init_once(void *context DISPATCH_UNUSED) |
| { |
| int wq_supported; |
| _dispatch_fork_becomes_unsafe(); |
| if (!_dispatch_root_queues_init_workq(&wq_supported)) { |
| #if DISPATCH_ENABLE_THREAD_POOL |
| size_t i; |
| for (i = 0; i < DISPATCH_ROOT_QUEUE_COUNT; i++) { |
| bool overcommit = true; |
| #if TARGET_OS_EMBEDDED || (DISPATCH_USE_INTERNAL_WORKQUEUE && HAVE_DISPATCH_WORKQ_MONITORING) |
| // some software hangs if the non-overcommitting queues do not |
| // overcommit when threads block. Someday, this behavior should |
| // apply to all platforms |
| if (!(i & 1)) { |
| overcommit = false; |
| } |
| #endif |
| _dispatch_root_queue_init_pthread_pool( |
| &_dispatch_root_queue_contexts[i], 0, overcommit); |
| } |
| #else |
| DISPATCH_INTERNAL_CRASH((errno << 16) | wq_supported, |
| "Root queue initialization failed"); |
| #endif // DISPATCH_ENABLE_THREAD_POOL |
| } |
| } |
| |
| void |
| _dispatch_root_queues_init(void) |
| { |
| static dispatch_once_t _dispatch_root_queues_pred; |
| dispatch_once_f(&_dispatch_root_queues_pred, NULL, |
| _dispatch_root_queues_init_once); |
| } |
| |
| DISPATCH_EXPORT DISPATCH_NOTHROW |
| void |
| libdispatch_init(void) |
| { |
| dispatch_assert(DISPATCH_ROOT_QUEUE_COUNT == 2 * DISPATCH_QOS_MAX); |
| |
| dispatch_assert(DISPATCH_QUEUE_PRIORITY_LOW == |
| -DISPATCH_QUEUE_PRIORITY_HIGH); |
| dispatch_assert(countof(_dispatch_root_queues) == |
| DISPATCH_ROOT_QUEUE_COUNT); |
| dispatch_assert(countof(_dispatch_root_queue_contexts) == |
| DISPATCH_ROOT_QUEUE_COUNT); |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| dispatch_assert(sizeof(_dispatch_wq2root_queues) / |
| sizeof(_dispatch_wq2root_queues[0][0]) == |
| WORKQ_NUM_PRIOQUEUE * 2); |
| #endif |
| #if DISPATCH_ENABLE_THREAD_POOL |
| dispatch_assert(countof(_dispatch_pthread_root_queue_contexts) == |
| DISPATCH_ROOT_QUEUE_COUNT); |
| #endif |
| |
| dispatch_assert(offsetof(struct dispatch_continuation_s, do_next) == |
| offsetof(struct dispatch_object_s, do_next)); |
| dispatch_assert(offsetof(struct dispatch_continuation_s, do_vtable) == |
| offsetof(struct dispatch_object_s, do_vtable)); |
| dispatch_assert(sizeof(struct dispatch_apply_s) <= |
| DISPATCH_CONTINUATION_SIZE); |
| dispatch_assert(sizeof(struct dispatch_queue_s) % DISPATCH_CACHELINE_SIZE |
| == 0); |
| dispatch_assert(offsetof(struct dispatch_queue_s, dq_state) % _Alignof(uint64_t) == 0); |
| dispatch_assert(sizeof(struct dispatch_root_queue_context_s) % |
| DISPATCH_CACHELINE_SIZE == 0); |
| |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| dispatch_qos_t qos = _dispatch_qos_from_qos_class(qos_class_main()); |
| dispatch_priority_t pri = _dispatch_priority_make(qos, 0); |
| _dispatch_main_q.dq_priority = _dispatch_priority_with_override_qos(pri, qos); |
| #if DISPATCH_DEBUG |
| if (!slowpath(getenv("LIBDISPATCH_DISABLE_SET_QOS"))) { |
| _dispatch_set_qos_class_enabled = 1; |
| } |
| #endif |
| #endif |
| |
| #if DISPATCH_USE_THREAD_LOCAL_STORAGE |
| _dispatch_thread_key_create(&__dispatch_tsd_key, _libdispatch_tsd_cleanup); |
| #else |
| _dispatch_thread_key_create(&dispatch_priority_key, NULL); |
| _dispatch_thread_key_create(&dispatch_r2k_key, NULL); |
| _dispatch_thread_key_create(&dispatch_queue_key, _dispatch_queue_cleanup); |
| _dispatch_thread_key_create(&dispatch_frame_key, _dispatch_frame_cleanup); |
| _dispatch_thread_key_create(&dispatch_cache_key, _dispatch_cache_cleanup); |
| _dispatch_thread_key_create(&dispatch_context_key, _dispatch_context_cleanup); |
| _dispatch_thread_key_create(&dispatch_pthread_root_queue_observer_hooks_key, |
| NULL); |
| _dispatch_thread_key_create(&dispatch_basepri_key, NULL); |
| #if DISPATCH_INTROSPECTION |
| _dispatch_thread_key_create(&dispatch_introspection_key , NULL); |
| #elif DISPATCH_PERF_MON |
| _dispatch_thread_key_create(&dispatch_bcounter_key, NULL); |
| #endif |
| _dispatch_thread_key_create(&dispatch_wlh_key, _dispatch_wlh_cleanup); |
| _dispatch_thread_key_create(&dispatch_voucher_key, _voucher_thread_cleanup); |
| _dispatch_thread_key_create(&dispatch_deferred_items_key, |
| _dispatch_deferred_items_cleanup); |
| #endif |
| |
| #if DISPATCH_USE_RESOLVERS // rdar://problem/8541707 |
| _dispatch_main_q.do_targetq = &_dispatch_root_queues[ |
| DISPATCH_ROOT_QUEUE_IDX_DEFAULT_QOS_OVERCOMMIT]; |
| #endif |
| |
| _dispatch_queue_set_current(&_dispatch_main_q); |
| _dispatch_queue_set_bound_thread(&_dispatch_main_q); |
| |
| #if DISPATCH_USE_PTHREAD_ATFORK |
| (void)dispatch_assume_zero(pthread_atfork(dispatch_atfork_prepare, |
| dispatch_atfork_parent, dispatch_atfork_child)); |
| #endif |
| _dispatch_hw_config_init(); |
| _dispatch_time_init(); |
| _dispatch_vtable_init(); |
| _os_object_init(); |
| _voucher_init(); |
| _dispatch_introspection_init(); |
| } |
| |
| #if DISPATCH_USE_THREAD_LOCAL_STORAGE |
| #if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__)) |
| #include <unistd.h> |
| #endif |
| #if !defined(_WIN32) |
| #include <sys/syscall.h> |
| #endif |
| |
| #ifndef __ANDROID__ |
| #ifdef SYS_gettid |
| DISPATCH_ALWAYS_INLINE |
| static inline pid_t |
| gettid(void) |
| { |
| return (pid_t)syscall(SYS_gettid); |
| } |
| #elif defined(__FreeBSD__) |
| DISPATCH_ALWAYS_INLINE |
| static inline pid_t |
| gettid(void) |
| { |
| return (pid_t)pthread_getthreadid_np(); |
| } |
| #elif defined(_WIN32) |
| DISPATCH_ALWAYS_INLINE |
| static inline DWORD |
| gettid(void) |
| { |
| return GetCurrentThreadId(); |
| } |
| #else |
| #error "SYS_gettid unavailable on this system" |
| #endif /* SYS_gettid */ |
| #endif /* ! __ANDROID__ */ |
| |
| #define _tsd_call_cleanup(k, f) do { \ |
| if ((f) && tsd->k) ((void(*)(void*))(f))(tsd->k); \ |
| } while (0) |
| |
| #ifdef __ANDROID__ |
| static void (*_dispatch_thread_detach_callback)(void); |
| |
| void |
| _dispatch_install_thread_detach_callback(dispatch_function_t cb) |
| { |
| if (os_atomic_xchg(&_dispatch_thread_detach_callback, cb, relaxed)) { |
| DISPATCH_CLIENT_CRASH(0, "Installing a thread detach callback twice"); |
| } |
| } |
| #endif |
| |
| #if defined(_WIN32) |
| static bool |
| _dispatch_process_is_exiting(void) |
| { |
| // The goal here is to detect if the current thread is executing cleanup |
| // code (e.g. FLS destructors) as a result of calling ExitProcess(). Windows |
| // doesn't provide an official method of getting this information, so we |
| // take advantage of how ExitProcess() works internally. The first thing |
| // that it does (according to MSDN) is terminate every other thread in the |
| // process. Logically, it should not be possible to create more threads |
| // after this point, and Windows indeed enforces this. Try to create a |
| // lightweight suspended thread, and if access is denied, assume that this |
| // is because the process is exiting. |
| // |
| // We aren't worried about any race conditions here during process exit. |
| // Cleanup code is only run on the thread that already called ExitProcess(), |
| // and every other thread will have been forcibly terminated by the time |
| // that happens. Additionally, while CreateThread() could conceivably fail |
| // due to resource exhaustion, the process would already be in a bad state |
| // if that happens. This is only intended to prevent unwanted cleanup code |
| // from running, so the worst case is that a thread doesn't clean up after |
| // itself when the process is about to die anyway. |
| const size_t stack_size = 1; // As small as possible |
| HANDLE thread = CreateThread(NULL, stack_size, NULL, NULL, |
| CREATE_SUSPENDED | STACK_SIZE_PARAM_IS_A_RESERVATION, NULL); |
| if (thread) { |
| // Although Microsoft recommends against using TerminateThread, it's |
| // safe to use it here because we know that the thread is suspended and |
| // it has not executed any code due to a NULL lpStartAddress. There was |
| // a bug in Windows Server 2003 and Windows XP where the initial stack |
| // would not be freed, but libdispatch does not support them anyway. |
| TerminateThread(thread, 0); |
| CloseHandle(thread); |
| return false; |
| } |
| return GetLastError() == ERROR_ACCESS_DENIED; |
| } |
| #endif |
| |
| void DISPATCH_TSD_DTOR_CC |
| _libdispatch_tsd_cleanup(void *ctx) |
| { |
| #if defined(_WIN32) |
| // On Windows, exiting a process will still call FLS destructors for the |
| // thread that called ExitProcess(). pthreads-based platforms don't call key |
| // destructors on exit, so be consistent. |
| if (_dispatch_process_is_exiting()) { |
| return; |
| } |
| #endif |
| |
| struct dispatch_tsd *tsd = (struct dispatch_tsd*) ctx; |
| |
| _tsd_call_cleanup(dispatch_priority_key, NULL); |
| _tsd_call_cleanup(dispatch_r2k_key, NULL); |
| |
| _tsd_call_cleanup(dispatch_queue_key, _dispatch_queue_cleanup); |
| _tsd_call_cleanup(dispatch_frame_key, _dispatch_frame_cleanup); |
| _tsd_call_cleanup(dispatch_cache_key, _dispatch_cache_cleanup); |
| _tsd_call_cleanup(dispatch_context_key, _dispatch_context_cleanup); |
| _tsd_call_cleanup(dispatch_pthread_root_queue_observer_hooks_key, |
| NULL); |
| _tsd_call_cleanup(dispatch_basepri_key, NULL); |
| #if DISPATCH_INTROSPECTION |
| _tsd_call_cleanup(dispatch_introspection_key, NULL); |
| #elif DISPATCH_PERF_MON |
| _tsd_call_cleanup(dispatch_bcounter_key, NULL); |
| #endif |
| _tsd_call_cleanup(dispatch_wlh_key, _dispatch_wlh_cleanup); |
| _tsd_call_cleanup(dispatch_voucher_key, _voucher_thread_cleanup); |
| _tsd_call_cleanup(dispatch_deferred_items_key, |
| _dispatch_deferred_items_cleanup); |
| #ifdef __ANDROID__ |
| if (_dispatch_thread_detach_callback) { |
| _dispatch_thread_detach_callback(); |
| } |
| #endif |
| tsd->tid = 0; |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| libdispatch_tsd_init(void) |
| { |
| #if defined(_WIN32) |
| FlsSetValue(__dispatch_tsd_key, &__dispatch_tsd); |
| #else |
| pthread_setspecific(__dispatch_tsd_key, &__dispatch_tsd); |
| #endif /* defined(_WIN32) */ |
| __dispatch_tsd.tid = gettid(); |
| } |
| #endif |
| |
| DISPATCH_NOTHROW |
| void |
| _dispatch_queue_atfork_child(void) |
| { |
| dispatch_queue_t main_q = &_dispatch_main_q; |
| void *crash = (void *)0x100; |
| size_t i; |
| |
| if (_dispatch_queue_is_thread_bound(main_q)) { |
| _dispatch_queue_set_bound_thread(main_q); |
| } |
| |
| if (!_dispatch_is_multithreaded_inline()) return; |
| |
| main_q->dq_items_head = crash; |
| main_q->dq_items_tail = crash; |
| |
| _dispatch_mgr_q.dq_items_head = crash; |
| _dispatch_mgr_q.dq_items_tail = crash; |
| |
| for (i = 0; i < DISPATCH_ROOT_QUEUE_COUNT; i++) { |
| _dispatch_root_queues[i].dq_items_head = crash; |
| _dispatch_root_queues[i].dq_items_tail = crash; |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_fork_becomes_unsafe_slow(void) |
| { |
| uint8_t value = os_atomic_or(&_dispatch_unsafe_fork, |
| _DISPATCH_UNSAFE_FORK_MULTITHREADED, relaxed); |
| if (value & _DISPATCH_UNSAFE_FORK_PROHIBIT) { |
| DISPATCH_CLIENT_CRASH(0, "Transition to multithreaded is prohibited"); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_prohibit_transition_to_multithreaded(bool prohibit) |
| { |
| if (prohibit) { |
| uint8_t value = os_atomic_or(&_dispatch_unsafe_fork, |
| _DISPATCH_UNSAFE_FORK_PROHIBIT, relaxed); |
| if (value & _DISPATCH_UNSAFE_FORK_MULTITHREADED) { |
| DISPATCH_CLIENT_CRASH(0, "The executable is already multithreaded"); |
| } |
| } else { |
| os_atomic_and(&_dispatch_unsafe_fork, |
| (uint8_t)~_DISPATCH_UNSAFE_FORK_PROHIBIT, relaxed); |
| } |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_attr_t |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_qos_class_valid(dispatch_qos_class_t qos_class, int relative_priority) |
| { |
| qos_class_t qos = (qos_class_t)qos_class; |
| switch (qos) { |
| case QOS_CLASS_MAINTENANCE: |
| case QOS_CLASS_BACKGROUND: |
| case QOS_CLASS_UTILITY: |
| case QOS_CLASS_DEFAULT: |
| case QOS_CLASS_USER_INITIATED: |
| case QOS_CLASS_USER_INTERACTIVE: |
| case QOS_CLASS_UNSPECIFIED: |
| break; |
| default: |
| return false; |
| } |
| if (relative_priority > 0 || relative_priority < QOS_MIN_RELATIVE_PRIORITY){ |
| return false; |
| } |
| return true; |
| } |
| |
| #define DISPATCH_QUEUE_ATTR_OVERCOMMIT2IDX(overcommit) \ |
| ((overcommit) == _dispatch_queue_attr_overcommit_disabled ? \ |
| DQA_INDEX_NON_OVERCOMMIT : \ |
| ((overcommit) == _dispatch_queue_attr_overcommit_enabled ? \ |
| DQA_INDEX_OVERCOMMIT : DQA_INDEX_UNSPECIFIED_OVERCOMMIT)) |
| |
| #define DISPATCH_QUEUE_ATTR_CONCURRENT2IDX(concurrent) \ |
| ((concurrent) ? DQA_INDEX_CONCURRENT : DQA_INDEX_SERIAL) |
| |
| #define DISPATCH_QUEUE_ATTR_INACTIVE2IDX(inactive) \ |
| ((inactive) ? DQA_INDEX_INACTIVE : DQA_INDEX_ACTIVE) |
| |
| #define DISPATCH_QUEUE_ATTR_AUTORELEASE_FREQUENCY2IDX(frequency) \ |
| (frequency) |
| |
| #define DISPATCH_QUEUE_ATTR_PRIO2IDX(prio) (-(prio)) |
| |
| #define DISPATCH_QUEUE_ATTR_QOS2IDX(qos) (qos) |
| |
| static inline dispatch_queue_attr_t |
| _dispatch_get_queue_attr(dispatch_qos_t qos, int prio, |
| _dispatch_queue_attr_overcommit_t overcommit, |
| dispatch_autorelease_frequency_t frequency, |
| bool concurrent, bool inactive) |
| { |
| return (dispatch_queue_attr_t)&_dispatch_queue_attrs |
| [DISPATCH_QUEUE_ATTR_QOS2IDX(qos)] |
| [DISPATCH_QUEUE_ATTR_PRIO2IDX(prio)] |
| [DISPATCH_QUEUE_ATTR_OVERCOMMIT2IDX(overcommit)] |
| [DISPATCH_QUEUE_ATTR_AUTORELEASE_FREQUENCY2IDX(frequency)] |
| [DISPATCH_QUEUE_ATTR_CONCURRENT2IDX(concurrent)] |
| [DISPATCH_QUEUE_ATTR_INACTIVE2IDX(inactive)]; |
| } |
| |
| dispatch_queue_attr_t |
| _dispatch_get_default_queue_attr(void) |
| { |
| return _dispatch_get_queue_attr(DISPATCH_QOS_UNSPECIFIED, 0, |
| _dispatch_queue_attr_overcommit_unspecified, |
| DISPATCH_AUTORELEASE_FREQUENCY_INHERIT, false, false); |
| } |
| |
| dispatch_queue_attr_t |
| dispatch_queue_attr_make_with_qos_class(dispatch_queue_attr_t dqa, |
| dispatch_qos_class_t qos_class, int relpri) |
| { |
| if (!_dispatch_qos_class_valid(qos_class, relpri)) { |
| return DISPATCH_BAD_INPUT; |
| } |
| if (!slowpath(dqa)) { |
| dqa = _dispatch_get_default_queue_attr(); |
| } else if (dqa->do_vtable != DISPATCH_VTABLE(queue_attr)) { |
| DISPATCH_CLIENT_CRASH(dqa->do_vtable, "Invalid queue attribute"); |
| } |
| return _dispatch_get_queue_attr(_dispatch_qos_from_qos_class(qos_class), |
| relpri, dqa->dqa_overcommit, dqa->dqa_autorelease_frequency, |
| dqa->dqa_concurrent, dqa->dqa_inactive); |
| } |
| |
| dispatch_queue_attr_t |
| dispatch_queue_attr_make_initially_inactive(dispatch_queue_attr_t dqa) |
| { |
| if (!slowpath(dqa)) { |
| dqa = _dispatch_get_default_queue_attr(); |
| } else if (dqa->do_vtable != DISPATCH_VTABLE(queue_attr)) { |
| DISPATCH_CLIENT_CRASH(dqa->do_vtable, "Invalid queue attribute"); |
| } |
| dispatch_priority_t pri = dqa->dqa_qos_and_relpri; |
| return _dispatch_get_queue_attr(_dispatch_priority_qos(pri), |
| _dispatch_priority_relpri(pri), dqa->dqa_overcommit, |
| dqa->dqa_autorelease_frequency, dqa->dqa_concurrent, true); |
| } |
| |
| dispatch_queue_attr_t |
| dispatch_queue_attr_make_with_overcommit(dispatch_queue_attr_t dqa, |
| bool overcommit) |
| { |
| if (!slowpath(dqa)) { |
| dqa = _dispatch_get_default_queue_attr(); |
| } else if (dqa->do_vtable != DISPATCH_VTABLE(queue_attr)) { |
| DISPATCH_CLIENT_CRASH(dqa->do_vtable, "Invalid queue attribute"); |
| } |
| dispatch_priority_t pri = dqa->dqa_qos_and_relpri; |
| return _dispatch_get_queue_attr(_dispatch_priority_qos(pri), |
| _dispatch_priority_relpri(pri), overcommit ? |
| _dispatch_queue_attr_overcommit_enabled : |
| _dispatch_queue_attr_overcommit_disabled, |
| dqa->dqa_autorelease_frequency, dqa->dqa_concurrent, |
| dqa->dqa_inactive); |
| } |
| |
| dispatch_queue_attr_t |
| dispatch_queue_attr_make_with_autorelease_frequency(dispatch_queue_attr_t dqa, |
| dispatch_autorelease_frequency_t frequency) |
| { |
| switch (frequency) { |
| case DISPATCH_AUTORELEASE_FREQUENCY_INHERIT: |
| case DISPATCH_AUTORELEASE_FREQUENCY_WORK_ITEM: |
| case DISPATCH_AUTORELEASE_FREQUENCY_NEVER: |
| break; |
| } |
| if (!slowpath(dqa)) { |
| dqa = _dispatch_get_default_queue_attr(); |
| } else if (dqa->do_vtable != DISPATCH_VTABLE(queue_attr)) { |
| DISPATCH_CLIENT_CRASH(dqa->do_vtable, "Invalid queue attribute"); |
| } |
| dispatch_priority_t pri = dqa->dqa_qos_and_relpri; |
| return _dispatch_get_queue_attr(_dispatch_priority_qos(pri), |
| _dispatch_priority_relpri(pri), dqa->dqa_overcommit, |
| frequency, dqa->dqa_concurrent, dqa->dqa_inactive); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_t |
| |
| void |
| dispatch_queue_set_label_nocopy(dispatch_queue_t dq, const char *label) |
| { |
| if (dq->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT) { |
| return; |
| } |
| dispatch_queue_flags_t dqf = _dispatch_queue_atomic_flags(dq); |
| if (unlikely(dqf & DQF_LABEL_NEEDS_FREE)) { |
| DISPATCH_CLIENT_CRASH(dq, "Cannot change label for this queue"); |
| } |
| dq->dq_label = label; |
| } |
| |
| static inline bool |
| _dispatch_base_queue_is_wlh(dispatch_queue_t dq, dispatch_queue_t tq) |
| { |
| (void)dq; (void)tq; |
| return false; |
| } |
| |
| static void |
| _dispatch_queue_inherit_wlh_from_target(dispatch_queue_t dq, |
| dispatch_queue_t tq) |
| { |
| uint64_t old_state, new_state, role; |
| |
| if (!dx_hastypeflag(tq, QUEUE_ROOT)) { |
| role = DISPATCH_QUEUE_ROLE_INNER; |
| } else if (_dispatch_base_queue_is_wlh(dq, tq)) { |
| role = DISPATCH_QUEUE_ROLE_BASE_WLH; |
| } else { |
| role = DISPATCH_QUEUE_ROLE_BASE_ANON; |
| } |
| |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| new_state = old_state & ~DISPATCH_QUEUE_ROLE_MASK; |
| new_state |= role; |
| if (old_state == new_state) { |
| os_atomic_rmw_loop_give_up(break); |
| } |
| }); |
| |
| dispatch_wlh_t cur_wlh = _dispatch_get_wlh(); |
| if (cur_wlh == (dispatch_wlh_t)dq && !_dq_state_is_base_wlh(new_state)) { |
| _dispatch_event_loop_leave_immediate(cur_wlh, new_state); |
| } |
| if (!dx_hastypeflag(tq, QUEUE_ROOT)) { |
| #if DISPATCH_ALLOW_NON_LEAF_RETARGET |
| _dispatch_queue_atomic_flags_set(tq, DQF_TARGETED); |
| #else |
| _dispatch_queue_atomic_flags_set_and_clear(tq, DQF_TARGETED, DQF_LEGACY); |
| #endif |
| } |
| } |
| |
| unsigned long volatile _dispatch_queue_serial_numbers = |
| DISPATCH_QUEUE_SERIAL_NUMBER_INIT; |
| |
| dispatch_priority_t |
| _dispatch_queue_compute_priority_and_wlh(dispatch_queue_t dq, |
| dispatch_wlh_t *wlh_out) |
| { |
| dispatch_priority_t p = dq->dq_priority & DISPATCH_PRIORITY_REQUESTED_MASK; |
| dispatch_queue_t tq = dq->do_targetq; |
| dispatch_priority_t tqp = tq->dq_priority &DISPATCH_PRIORITY_REQUESTED_MASK; |
| dispatch_wlh_t wlh = DISPATCH_WLH_ANON; |
| |
| if (_dq_state_is_base_wlh(dq->dq_state)) { |
| wlh = (dispatch_wlh_t)dq; |
| } |
| |
| while (unlikely(!dx_hastypeflag(tq, QUEUE_ROOT))) { |
| if (unlikely(tq == &_dispatch_mgr_q)) { |
| if (wlh_out) *wlh_out = DISPATCH_WLH_ANON; |
| return DISPATCH_PRIORITY_FLAG_MANAGER; |
| } |
| if (unlikely(_dispatch_queue_is_thread_bound(tq))) { |
| // thread-bound hierarchies are weird, we need to install |
| // from the context of the thread this hierarchy is bound to |
| if (wlh_out) *wlh_out = NULL; |
| return 0; |
| } |
| if (unlikely(DISPATCH_QUEUE_IS_SUSPENDED(tq))) { |
| // this queue may not be activated yet, so the queue graph may not |
| // have stabilized yet |
| _dispatch_ktrace1(DISPATCH_PERF_delayed_registration, dq); |
| if (wlh_out) *wlh_out = NULL; |
| return 0; |
| } |
| |
| if (_dq_state_is_base_wlh(tq->dq_state)) { |
| wlh = (dispatch_wlh_t)tq; |
| } else if (unlikely(_dispatch_queue_is_legacy(tq))) { |
| // we're not allowed to dereference tq->do_targetq |
| _dispatch_ktrace1(DISPATCH_PERF_delayed_registration, dq); |
| if (wlh_out) *wlh_out = NULL; |
| return 0; |
| } |
| |
| if (!(tq->dq_priority & DISPATCH_PRIORITY_FLAG_INHERIT)) { |
| if (p < tqp) p = tqp; |
| } |
| tq = tq->do_targetq; |
| tqp = tq->dq_priority & DISPATCH_PRIORITY_REQUESTED_MASK; |
| } |
| |
| if (unlikely(!tqp)) { |
| // pthread root queues opt out of QoS |
| if (wlh_out) *wlh_out = DISPATCH_WLH_ANON; |
| return DISPATCH_PRIORITY_FLAG_MANAGER; |
| } |
| if (wlh_out) *wlh_out = wlh; |
| return _dispatch_priority_inherit_from_root_queue(p, tq); |
| } |
| |
| DISPATCH_NOINLINE |
| static dispatch_queue_t |
| _dispatch_queue_create_with_target(const char *label, dispatch_queue_attr_t dqa, |
| dispatch_queue_t tq, bool legacy) |
| { |
| if (!slowpath(dqa)) { |
| dqa = _dispatch_get_default_queue_attr(); |
| } else if (dqa->do_vtable != DISPATCH_VTABLE(queue_attr)) { |
| DISPATCH_CLIENT_CRASH(dqa->do_vtable, "Invalid queue attribute"); |
| } |
| |
| // |
| // Step 1: Normalize arguments (qos, overcommit, tq) |
| // |
| |
| dispatch_qos_t qos = _dispatch_priority_qos(dqa->dqa_qos_and_relpri); |
| #if !HAVE_PTHREAD_WORKQUEUE_QOS |
| if (qos == DISPATCH_QOS_USER_INTERACTIVE) { |
| qos = DISPATCH_QOS_USER_INITIATED; |
| } |
| if (qos == DISPATCH_QOS_MAINTENANCE) { |
| qos = DISPATCH_QOS_BACKGROUND; |
| } |
| #endif // !HAVE_PTHREAD_WORKQUEUE_QOS |
| |
| _dispatch_queue_attr_overcommit_t overcommit = dqa->dqa_overcommit; |
| if (overcommit != _dispatch_queue_attr_overcommit_unspecified && tq) { |
| if (tq->do_targetq) { |
| DISPATCH_CLIENT_CRASH(tq, "Cannot specify both overcommit and " |
| "a non-global target queue"); |
| } |
| } |
| |
| if (tq && !tq->do_targetq && |
| tq->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT) { |
| // Handle discrepancies between attr and target queue, attributes win |
| if (overcommit == _dispatch_queue_attr_overcommit_unspecified) { |
| if (tq->dq_priority & DISPATCH_PRIORITY_FLAG_OVERCOMMIT) { |
| overcommit = _dispatch_queue_attr_overcommit_enabled; |
| } else { |
| overcommit = _dispatch_queue_attr_overcommit_disabled; |
| } |
| } |
| if (qos == DISPATCH_QOS_UNSPECIFIED) { |
| dispatch_qos_t tq_qos = _dispatch_priority_qos(tq->dq_priority); |
| tq = _dispatch_get_root_queue(tq_qos, |
| overcommit == _dispatch_queue_attr_overcommit_enabled); |
| } else { |
| tq = NULL; |
| } |
| } else if (tq && !tq->do_targetq) { |
| // target is a pthread or runloop root queue, setting QoS or overcommit |
| // is disallowed |
| if (overcommit != _dispatch_queue_attr_overcommit_unspecified) { |
| DISPATCH_CLIENT_CRASH(tq, "Cannot specify an overcommit attribute " |
| "and use this kind of target queue"); |
| } |
| if (qos != DISPATCH_QOS_UNSPECIFIED) { |
| DISPATCH_CLIENT_CRASH(tq, "Cannot specify a QoS attribute " |
| "and use this kind of target queue"); |
| } |
| } else { |
| if (overcommit == _dispatch_queue_attr_overcommit_unspecified) { |
| // Serial queues default to overcommit! |
| overcommit = dqa->dqa_concurrent ? |
| _dispatch_queue_attr_overcommit_disabled : |
| _dispatch_queue_attr_overcommit_enabled; |
| } |
| } |
| if (!tq) { |
| tq = _dispatch_get_root_queue( |
| qos == DISPATCH_QOS_UNSPECIFIED ? DISPATCH_QOS_DEFAULT : qos, |
| overcommit == _dispatch_queue_attr_overcommit_enabled); |
| if (slowpath(!tq)) { |
| DISPATCH_CLIENT_CRASH(qos, "Invalid queue attribute"); |
| } |
| } |
| |
| // |
| // Step 2: Initialize the queue |
| // |
| |
| if (legacy) { |
| // if any of these attributes is specified, use non legacy classes |
| if (dqa->dqa_inactive || dqa->dqa_autorelease_frequency) { |
| legacy = false; |
| } |
| } |
| |
| const void *vtable; |
| dispatch_queue_flags_t dqf = 0; |
| if (legacy) { |
| vtable = DISPATCH_VTABLE(queue); |
| } else if (dqa->dqa_concurrent) { |
| vtable = DISPATCH_VTABLE(queue_concurrent); |
| } else { |
| vtable = DISPATCH_VTABLE(queue_serial); |
| } |
| switch (dqa->dqa_autorelease_frequency) { |
| case DISPATCH_AUTORELEASE_FREQUENCY_NEVER: |
| dqf |= DQF_AUTORELEASE_NEVER; |
| break; |
| case DISPATCH_AUTORELEASE_FREQUENCY_WORK_ITEM: |
| dqf |= DQF_AUTORELEASE_ALWAYS; |
| break; |
| } |
| if (legacy) { |
| dqf |= DQF_LEGACY; |
| } |
| if (label) { |
| const char *tmp = _dispatch_strdup_if_mutable(label); |
| if (tmp != label) { |
| dqf |= DQF_LABEL_NEEDS_FREE; |
| label = tmp; |
| } |
| } |
| |
| dispatch_queue_t dq = _dispatch_object_alloc(vtable, |
| sizeof(struct dispatch_queue_s) - DISPATCH_QUEUE_CACHELINE_PAD); |
| _dispatch_queue_init(dq, dqf, dqa->dqa_concurrent ? |
| DISPATCH_QUEUE_WIDTH_MAX : 1, DISPATCH_QUEUE_ROLE_INNER | |
| (dqa->dqa_inactive ? DISPATCH_QUEUE_INACTIVE : 0)); |
| |
| dq->dq_label = label; |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| dq->dq_priority = dqa->dqa_qos_and_relpri; |
| if (overcommit == _dispatch_queue_attr_overcommit_enabled) { |
| dq->dq_priority |= DISPATCH_PRIORITY_FLAG_OVERCOMMIT; |
| } |
| #endif |
| _dispatch_retain(tq); |
| if (qos == QOS_CLASS_UNSPECIFIED) { |
| // legacy way of inherithing the QoS from the target |
| _dispatch_queue_priority_inherit_from_target(dq, tq); |
| } |
| if (!dqa->dqa_inactive) { |
| _dispatch_queue_inherit_wlh_from_target(dq, tq); |
| } |
| dq->do_targetq = tq; |
| _dispatch_object_debug(dq, "%s", __func__); |
| return _dispatch_introspection_queue_create(dq); |
| } |
| |
| dispatch_queue_t |
| dispatch_queue_create_with_target(const char *label, dispatch_queue_attr_t dqa, |
| dispatch_queue_t tq) |
| { |
| return _dispatch_queue_create_with_target(label, dqa, tq, false); |
| } |
| |
| dispatch_queue_t |
| dispatch_queue_create(const char *label, dispatch_queue_attr_t attr) |
| { |
| return _dispatch_queue_create_with_target(label, attr, |
| DISPATCH_TARGET_QUEUE_DEFAULT, true); |
| } |
| |
| dispatch_queue_t |
| dispatch_queue_create_with_accounting_override_voucher(const char *label, |
| dispatch_queue_attr_t attr, voucher_t voucher) |
| { |
| (void)label; (void)attr; (void)voucher; |
| DISPATCH_CLIENT_CRASH(0, "Unsupported interface"); |
| } |
| |
| void |
| _dispatch_queue_destroy(dispatch_queue_t dq, bool *allow_free) |
| { |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| uint64_t initial_state = DISPATCH_QUEUE_STATE_INIT_VALUE(dq->dq_width); |
| |
| if (dx_hastypeflag(dq, QUEUE_ROOT)) { |
| initial_state = DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE; |
| } |
| dq_state &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| dq_state &= ~DISPATCH_QUEUE_DIRTY; |
| dq_state &= ~DISPATCH_QUEUE_ROLE_MASK; |
| if (slowpath(dq_state != initial_state)) { |
| if (_dq_state_drain_locked(dq_state)) { |
| DISPATCH_CLIENT_CRASH((uintptr_t)dq_state, |
| "Release of a locked queue"); |
| } |
| #ifndef __LP64__ |
| dq_state >>= 32; |
| #endif |
| DISPATCH_CLIENT_CRASH((uintptr_t)dq_state, |
| "Release of a queue with corrupt state"); |
| } |
| if (slowpath(dq->dq_items_tail)) { |
| DISPATCH_CLIENT_CRASH(dq->dq_items_tail, |
| "Release of a queue while items are enqueued"); |
| } |
| |
| // trash the queue so that use after free will crash |
| dq->dq_items_head = (void *)0x200; |
| dq->dq_items_tail = (void *)0x200; |
| |
| dispatch_queue_t dqsq = os_atomic_xchg2o(dq, dq_specific_q, |
| (void *)0x200, relaxed); |
| if (dqsq) { |
| _dispatch_release(dqsq); |
| } |
| |
| // fastpath for queues that never got their storage retained |
| if (likely(os_atomic_load2o(dq, dq_sref_cnt, relaxed) == 0)) { |
| // poison the state with something that is suspended and is easy to spot |
| dq->dq_state = 0xdead000000000000; |
| return; |
| } |
| |
| // Take over freeing the memory from _dispatch_object_dealloc() |
| // |
| // As soon as we call _dispatch_queue_release_storage(), we forfeit |
| // the possibility for the caller of dx_dispose() to finalize the object |
| // so that responsibility is ours. |
| _dispatch_object_finalize(dq); |
| *allow_free = false; |
| dq->dq_label = "<released queue, pending free>"; |
| dq->do_targetq = NULL; |
| dq->do_finalizer = NULL; |
| dq->do_ctxt = NULL; |
| return _dispatch_queue_release_storage(dq); |
| } |
| |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| void |
| _dispatch_queue_dispose(dispatch_queue_t dq, bool *allow_free) |
| { |
| _dispatch_object_debug(dq, "%s", __func__); |
| _dispatch_introspection_queue_dispose(dq); |
| if (dq->dq_label && _dispatch_queue_label_needs_free(dq)) { |
| free((void*)dq->dq_label); |
| } |
| _dispatch_queue_destroy(dq, allow_free); |
| } |
| |
| void |
| _dispatch_queue_xref_dispose(dispatch_queue_t dq) |
| { |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (unlikely(_dq_state_is_suspended(dq_state))) { |
| long state = (long)dq_state; |
| if (sizeof(long) < sizeof(uint64_t)) state = (long)(dq_state >> 32); |
| if (unlikely(_dq_state_is_inactive(dq_state))) { |
| // Arguments for and against this assert are within 6705399 |
| DISPATCH_CLIENT_CRASH(state, "Release of an inactive object"); |
| } |
| DISPATCH_CLIENT_CRASH(dq_state, "Release of a suspended object"); |
| } |
| os_atomic_or2o(dq, dq_atomic_flags, DQF_RELEASED, relaxed); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_suspend_slow(dispatch_queue_t dq) |
| { |
| uint64_t dq_state, value, delta; |
| |
| _dispatch_queue_sidelock_lock(dq); |
| |
| // what we want to transfer (remove from dq_state) |
| delta = DISPATCH_QUEUE_SUSPEND_HALF * DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| // but this is a suspend so add a suspend count at the same time |
| delta -= DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| if (dq->dq_side_suspend_cnt == 0) { |
| // we substract delta from dq_state, and we want to set this bit |
| delta -= DISPATCH_QUEUE_HAS_SIDE_SUSPEND_CNT; |
| } |
| |
| os_atomic_rmw_loop2o(dq, dq_state, dq_state, value, relaxed, { |
| // unsigned underflow of the substraction can happen because other |
| // threads could have touched this value while we were trying to acquire |
| // the lock, or because another thread raced us to do the same operation |
| // and got to the lock first. |
| if (unlikely(os_sub_overflow(dq_state, delta, &value))) { |
| os_atomic_rmw_loop_give_up(goto retry); |
| } |
| }); |
| if (unlikely(os_add_overflow(dq->dq_side_suspend_cnt, |
| DISPATCH_QUEUE_SUSPEND_HALF, &dq->dq_side_suspend_cnt))) { |
| DISPATCH_CLIENT_CRASH(0, "Too many nested calls to dispatch_suspend()"); |
| } |
| return _dispatch_queue_sidelock_unlock(dq); |
| |
| retry: |
| _dispatch_queue_sidelock_unlock(dq); |
| return dx_vtable(dq)->do_suspend(dq); |
| } |
| |
| void |
| _dispatch_queue_suspend(dispatch_queue_t dq) |
| { |
| dispatch_assert(dq->do_ref_cnt != DISPATCH_OBJECT_GLOBAL_REFCNT); |
| |
| uint64_t dq_state, value; |
| |
| os_atomic_rmw_loop2o(dq, dq_state, dq_state, value, relaxed, { |
| value = DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| if (unlikely(os_add_overflow(dq_state, value, &value))) { |
| os_atomic_rmw_loop_give_up({ |
| return _dispatch_queue_suspend_slow(dq); |
| }); |
| } |
| if (!_dq_state_drain_locked(dq_state)) { |
| value |= DLOCK_OWNER_MASK; |
| } |
| }); |
| |
| if (!_dq_state_is_suspended(dq_state)) { |
| // rdar://8181908 we need to extend the queue life for the duration |
| // of the call to wakeup at _dispatch_queue_resume() time. |
| _dispatch_retain_2(dq); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_resume_slow(dispatch_queue_t dq) |
| { |
| uint64_t dq_state, value, delta; |
| |
| _dispatch_queue_sidelock_lock(dq); |
| |
| // what we want to transfer |
| delta = DISPATCH_QUEUE_SUSPEND_HALF * DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| // but this is a resume so consume a suspend count at the same time |
| delta -= DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| switch (dq->dq_side_suspend_cnt) { |
| case 0: |
| goto retry; |
| case DISPATCH_QUEUE_SUSPEND_HALF: |
| // we will transition the side count to 0, so we want to clear this bit |
| delta -= DISPATCH_QUEUE_HAS_SIDE_SUSPEND_CNT; |
| break; |
| } |
| os_atomic_rmw_loop2o(dq, dq_state, dq_state, value, relaxed, { |
| // unsigned overflow of the addition can happen because other |
| // threads could have touched this value while we were trying to acquire |
| // the lock, or because another thread raced us to do the same operation |
| // and got to the lock first. |
| if (unlikely(os_add_overflow(dq_state, delta, &value))) { |
| os_atomic_rmw_loop_give_up(goto retry); |
| } |
| }); |
| dq->dq_side_suspend_cnt -= DISPATCH_QUEUE_SUSPEND_HALF; |
| return _dispatch_queue_sidelock_unlock(dq); |
| |
| retry: |
| _dispatch_queue_sidelock_unlock(dq); |
| return dx_vtable(dq)->do_resume(dq, false); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_resume_finalize_activation(dispatch_queue_t dq) |
| { |
| bool allow_resume = true; |
| // Step 2: run the activation finalizer |
| if (dx_vtable(dq)->do_finalize_activation) { |
| dx_vtable(dq)->do_finalize_activation(dq, &allow_resume); |
| } |
| // Step 3: consume the suspend count |
| if (allow_resume) { |
| return dx_vtable(dq)->do_resume(dq, false); |
| } |
| } |
| |
| void |
| _dispatch_queue_resume(dispatch_queue_t dq, bool activate) |
| { |
| // covers all suspend and inactive bits, including side suspend bit |
| const uint64_t suspend_bits = DISPATCH_QUEUE_SUSPEND_BITS_MASK; |
| uint64_t pending_barrier_width = |
| (dq->dq_width - 1) * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| uint64_t set_owner_and_set_full_width_and_in_barrier = |
| _dispatch_lock_value_for_self() | DISPATCH_QUEUE_WIDTH_FULL_BIT | |
| DISPATCH_QUEUE_IN_BARRIER; |
| |
| // backward compatibility: only dispatch sources can abuse |
| // dispatch_resume() to really mean dispatch_activate() |
| bool is_source = (dx_metatype(dq) == _DISPATCH_SOURCE_TYPE); |
| uint64_t dq_state, value; |
| |
| dispatch_assert(dq->do_ref_cnt != DISPATCH_OBJECT_GLOBAL_REFCNT); |
| |
| // Activation is a bit tricky as it needs to finalize before the wakeup. |
| // |
| // If after doing its updates to the suspend count and/or inactive bit, |
| // the last suspension related bit that would remain is the |
| // NEEDS_ACTIVATION one, then this function: |
| // |
| // 1. moves the state to { sc:1 i:0 na:0 } (converts the needs-activate into |
| // a suspend count) |
| // 2. runs the activation finalizer |
| // 3. consumes the suspend count set in (1), and finishes the resume flow |
| // |
| // Concurrently, some property setters such as setting dispatch source |
| // handlers or _dispatch_queue_set_target_queue try to do in-place changes |
| // before activation. These protect their action by taking a suspend count. |
| // Step (1) above cannot happen if such a setter has locked the object. |
| if (activate) { |
| // relaxed atomic because this doesn't publish anything, this is only |
| // about picking the thread that gets to finalize the activation |
| os_atomic_rmw_loop2o(dq, dq_state, dq_state, value, relaxed, { |
| if ((dq_state & suspend_bits) == |
| DISPATCH_QUEUE_NEEDS_ACTIVATION + DISPATCH_QUEUE_INACTIVE) { |
| // { sc:0 i:1 na:1 } -> { sc:1 i:0 na:0 } |
| value = dq_state - DISPATCH_QUEUE_INACTIVE |
| - DISPATCH_QUEUE_NEEDS_ACTIVATION |
| + DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| } else if (_dq_state_is_inactive(dq_state)) { |
| // { sc:>0 i:1 na:1 } -> { i:0 na:1 } |
| // simple activation because sc is not 0 |
| // resume will deal with na:1 later |
| value = dq_state - DISPATCH_QUEUE_INACTIVE; |
| } else { |
| // object already active, this is a no-op, just exit |
| os_atomic_rmw_loop_give_up(return); |
| } |
| }); |
| } else { |
| // release barrier needed to publish the effect of |
| // - dispatch_set_target_queue() |
| // - dispatch_set_*_handler() |
| // - do_finalize_activation() |
| os_atomic_rmw_loop2o(dq, dq_state, dq_state, value, release, { |
| if ((dq_state & suspend_bits) == DISPATCH_QUEUE_SUSPEND_INTERVAL |
| + DISPATCH_QUEUE_NEEDS_ACTIVATION) { |
| // { sc:1 i:0 na:1 } -> { sc:1 i:0 na:0 } |
| value = dq_state - DISPATCH_QUEUE_NEEDS_ACTIVATION; |
| } else if (is_source && (dq_state & suspend_bits) == |
| DISPATCH_QUEUE_NEEDS_ACTIVATION + DISPATCH_QUEUE_INACTIVE) { |
| // { sc:0 i:1 na:1 } -> { sc:1 i:0 na:0 } |
| value = dq_state - DISPATCH_QUEUE_INACTIVE |
| - DISPATCH_QUEUE_NEEDS_ACTIVATION |
| + DISPATCH_QUEUE_SUSPEND_INTERVAL; |
| } else if (unlikely(os_sub_overflow(dq_state, |
| DISPATCH_QUEUE_SUSPEND_INTERVAL, &value))) { |
| // underflow means over-resume or a suspend count transfer |
| // to the side count is needed |
| os_atomic_rmw_loop_give_up({ |
| if (!(dq_state & DISPATCH_QUEUE_HAS_SIDE_SUSPEND_CNT)) { |
| goto over_resume; |
| } |
| return _dispatch_queue_resume_slow(dq); |
| }); |
| // |
| // below this, value = dq_state - DISPATCH_QUEUE_SUSPEND_INTERVAL |
| // |
| } else if (!_dq_state_is_runnable(value)) { |
| // Out of width or still suspended. |
| // For the former, force _dispatch_queue_non_barrier_complete |
| // to reconsider whether it has work to do |
| value |= DISPATCH_QUEUE_DIRTY; |
| } else if (!_dq_state_drain_locked_by(value, DLOCK_OWNER_MASK)) { |
| dispatch_assert(_dq_state_drain_locked(value)); |
| // still locked by someone else, make drain_try_unlock() fail |
| // and reconsider whether it has work to do |
| value |= DISPATCH_QUEUE_DIRTY; |
| } else if (!is_source && (_dq_state_has_pending_barrier(value) || |
| value + pending_barrier_width < |
| DISPATCH_QUEUE_WIDTH_FULL_BIT)) { |
| // if we can, acquire the full width drain lock |
| // and then perform a lock transfer |
| // |
| // However this is never useful for a source where there are no |
| // sync waiters, so never take the lock and do a plain wakeup |
| value &= DISPATCH_QUEUE_DRAIN_PRESERVED_BITS_MASK; |
| value |= set_owner_and_set_full_width_and_in_barrier; |
| } else { |
| // clear overrides and force a wakeup |
| value &= ~DISPATCH_QUEUE_DRAIN_UNLOCK_MASK; |
| value &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| } |
| }); |
| } |
| |
| if ((dq_state ^ value) & DISPATCH_QUEUE_NEEDS_ACTIVATION) { |
| // we cleared the NEEDS_ACTIVATION bit and we have a valid suspend count |
| return _dispatch_queue_resume_finalize_activation(dq); |
| } |
| |
| if (activate) { |
| // if we're still in an activate codepath here we should have |
| // { sc:>0 na:1 }, if not we've got a corrupt state |
| if (unlikely(!_dq_state_is_suspended(value))) { |
| DISPATCH_CLIENT_CRASH(dq, "Invalid suspension state"); |
| } |
| return; |
| } |
| |
| if (_dq_state_is_suspended(value)) { |
| return; |
| } |
| |
| if (_dq_state_is_dirty(dq_state)) { |
| // <rdar://problem/14637483> |
| // dependency ordering for dq state changes that were flushed |
| // and not acted upon |
| os_atomic_thread_fence(dependency); |
| dq = os_atomic_force_dependency_on(dq, dq_state); |
| } |
| // Balancing the retain_2 done in suspend() for rdar://8181908 |
| dispatch_wakeup_flags_t flags = DISPATCH_WAKEUP_CONSUME_2; |
| if ((dq_state ^ value) & DISPATCH_QUEUE_IN_BARRIER) { |
| flags |= DISPATCH_WAKEUP_BARRIER_COMPLETE; |
| } else if (!_dq_state_is_runnable(value)) { |
| if (_dq_state_is_base_wlh(dq_state)) { |
| _dispatch_event_loop_assert_not_owned((dispatch_wlh_t)dq); |
| } |
| return _dispatch_release_2(dq); |
| } |
| dispatch_assert(!_dq_state_received_sync_wait(dq_state)); |
| dispatch_assert(!_dq_state_in_sync_transfer(dq_state)); |
| return dx_wakeup(dq, _dq_state_max_qos(dq_state), flags); |
| |
| over_resume: |
| if (unlikely(_dq_state_is_inactive(dq_state))) { |
| DISPATCH_CLIENT_CRASH(dq, "Over-resume of an inactive object"); |
| } |
| DISPATCH_CLIENT_CRASH(dq, "Over-resume of an object"); |
| } |
| |
| const char * |
| dispatch_queue_get_label(dispatch_queue_t dq) |
| { |
| if (slowpath(dq == DISPATCH_CURRENT_QUEUE_LABEL)) { |
| dq = _dispatch_get_current_queue(); |
| } |
| return dq->dq_label ? dq->dq_label : ""; |
| } |
| |
| qos_class_t |
| dispatch_queue_get_qos_class(dispatch_queue_t dq, int *relpri_ptr) |
| { |
| dispatch_qos_class_t qos = _dispatch_priority_qos(dq->dq_priority); |
| if (relpri_ptr) { |
| *relpri_ptr = qos ? _dispatch_priority_relpri(dq->dq_priority) : 0; |
| } |
| return _dispatch_qos_to_qos_class(qos); |
| } |
| |
| static void |
| _dispatch_queue_set_width2(void *ctxt) |
| { |
| int w = (int)(intptr_t)ctxt; // intentional truncation |
| uint32_t tmp; |
| dispatch_queue_t dq = _dispatch_queue_get_current(); |
| |
| if (w >= 0) { |
| tmp = w ? (unsigned int)w : 1; |
| } else { |
| dispatch_qos_t qos = _dispatch_qos_from_pp(_dispatch_get_priority()); |
| switch (w) { |
| case DISPATCH_QUEUE_WIDTH_MAX_PHYSICAL_CPUS: |
| tmp = _dispatch_qos_max_parallelism(qos, |
| DISPATCH_MAX_PARALLELISM_PHYSICAL); |
| break; |
| case DISPATCH_QUEUE_WIDTH_ACTIVE_CPUS: |
| tmp = _dispatch_qos_max_parallelism(qos, |
| DISPATCH_MAX_PARALLELISM_ACTIVE); |
| break; |
| case DISPATCH_QUEUE_WIDTH_MAX_LOGICAL_CPUS: |
| default: |
| tmp = _dispatch_qos_max_parallelism(qos, 0); |
| break; |
| } |
| } |
| if (tmp > DISPATCH_QUEUE_WIDTH_MAX) { |
| tmp = DISPATCH_QUEUE_WIDTH_MAX; |
| } |
| |
| dispatch_queue_flags_t old_dqf, new_dqf; |
| os_atomic_rmw_loop2o(dq, dq_atomic_flags, old_dqf, new_dqf, relaxed, { |
| new_dqf = (old_dqf & DQF_FLAGS_MASK) | DQF_WIDTH(tmp); |
| }); |
| _dispatch_queue_inherit_wlh_from_target(dq, dq->do_targetq); |
| _dispatch_object_debug(dq, "%s", __func__); |
| } |
| |
| void |
| dispatch_queue_set_width(dispatch_queue_t dq, long width) |
| { |
| if (unlikely(dq->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT || |
| dx_hastypeflag(dq, QUEUE_ROOT) || |
| dx_hastypeflag(dq, QUEUE_BASE))) { |
| return; |
| } |
| |
| unsigned long type = dx_type(dq); |
| switch (type) { |
| case DISPATCH_QUEUE_LEGACY_TYPE: |
| case DISPATCH_QUEUE_CONCURRENT_TYPE: |
| break; |
| case DISPATCH_QUEUE_SERIAL_TYPE: |
| DISPATCH_CLIENT_CRASH(type, "Cannot set width of a serial queue"); |
| default: |
| DISPATCH_CLIENT_CRASH(type, "Unexpected dispatch object type"); |
| } |
| |
| if (likely((int)width >= 0)) { |
| _dispatch_barrier_trysync_or_async_f(dq, (void*)(intptr_t)width, |
| _dispatch_queue_set_width2); |
| } else { |
| // The negative width constants need to execute on the queue to |
| // query the queue QoS |
| _dispatch_barrier_async_detached_f(dq, (void*)(intptr_t)width, |
| _dispatch_queue_set_width2); |
| } |
| } |
| |
| static void |
| _dispatch_queue_legacy_set_target_queue(void *ctxt) |
| { |
| dispatch_queue_t dq = _dispatch_queue_get_current(); |
| dispatch_queue_t tq = ctxt; |
| dispatch_queue_t otq = dq->do_targetq; |
| |
| if (_dispatch_queue_atomic_flags(dq) & DQF_TARGETED) { |
| #if DISPATCH_ALLOW_NON_LEAF_RETARGET |
| _dispatch_ktrace3(DISPATCH_PERF_non_leaf_retarget, dq, otq, tq); |
| _dispatch_bug_deprecated("Changing the target of a queue " |
| "already targeted by other dispatch objects"); |
| #else |
| DISPATCH_CLIENT_CRASH(0, "Cannot change the target of a queue " |
| "already targeted by other dispatch objects"); |
| #endif |
| } |
| |
| _dispatch_queue_priority_inherit_from_target(dq, tq); |
| _dispatch_queue_inherit_wlh_from_target(dq, tq); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| // see _dispatch_queue_class_wakeup() |
| _dispatch_queue_sidelock_lock(dq); |
| #endif |
| dq->do_targetq = tq; |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| // see _dispatch_queue_class_wakeup() |
| _dispatch_queue_sidelock_unlock(dq); |
| #endif |
| |
| _dispatch_object_debug(dq, "%s", __func__); |
| _dispatch_introspection_target_queue_changed(dq); |
| _dispatch_release_tailcall(otq); |
| } |
| |
| void |
| _dispatch_queue_set_target_queue(dispatch_queue_t dq, dispatch_queue_t tq) |
| { |
| dispatch_assert(dq->do_ref_cnt != DISPATCH_OBJECT_GLOBAL_REFCNT && |
| dq->do_targetq); |
| |
| if (unlikely(!tq)) { |
| bool is_concurrent_q = (dq->dq_width > 1); |
| tq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, !is_concurrent_q); |
| } |
| |
| if (_dispatch_queue_try_inactive_suspend(dq)) { |
| _dispatch_object_set_target_queue_inline(dq, tq); |
| return dx_vtable(dq)->do_resume(dq, false); |
| } |
| |
| #if !DISPATCH_ALLOW_NON_LEAF_RETARGET |
| if (_dispatch_queue_atomic_flags(dq) & DQF_TARGETED) { |
| DISPATCH_CLIENT_CRASH(0, "Cannot change the target of a queue " |
| "already targeted by other dispatch objects"); |
| } |
| #endif |
| |
| if (unlikely(!_dispatch_queue_is_legacy(dq))) { |
| #if DISPATCH_ALLOW_NON_LEAF_RETARGET |
| if (_dispatch_queue_atomic_flags(dq) & DQF_TARGETED) { |
| DISPATCH_CLIENT_CRASH(0, "Cannot change the target of a queue " |
| "already targeted by other dispatch objects"); |
| } |
| #endif |
| DISPATCH_CLIENT_CRASH(0, "Cannot change the target of this object " |
| "after it has been activated"); |
| } |
| |
| unsigned long type = dx_type(dq); |
| switch (type) { |
| case DISPATCH_QUEUE_LEGACY_TYPE: |
| #if DISPATCH_ALLOW_NON_LEAF_RETARGET |
| if (_dispatch_queue_atomic_flags(dq) & DQF_TARGETED) { |
| _dispatch_bug_deprecated("Changing the target of a queue " |
| "already targeted by other dispatch objects"); |
| } |
| #endif |
| break; |
| case DISPATCH_SOURCE_KEVENT_TYPE: |
| case DISPATCH_MACH_CHANNEL_TYPE: |
| _dispatch_ktrace1(DISPATCH_PERF_post_activate_retarget, dq); |
| _dispatch_bug_deprecated("Changing the target of a source " |
| "after it has been activated"); |
| break; |
| default: |
| DISPATCH_CLIENT_CRASH(type, "Unexpected dispatch object type"); |
| } |
| |
| _dispatch_retain(tq); |
| return _dispatch_barrier_trysync_or_async_f(dq, tq, |
| _dispatch_queue_legacy_set_target_queue); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_mgr_queue |
| |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| static struct dispatch_pthread_root_queue_context_s |
| _dispatch_mgr_root_queue_pthread_context; |
| static struct dispatch_root_queue_context_s |
| _dispatch_mgr_root_queue_context = {{{ |
| #if DISPATCH_USE_WORKQUEUES |
| .dgq_kworkqueue = (void*)(~0ul), |
| #endif |
| .dgq_ctxt = &_dispatch_mgr_root_queue_pthread_context, |
| .dgq_thread_pool_size = 1, |
| }}}; |
| |
| static struct dispatch_queue_s _dispatch_mgr_root_queue = { |
| DISPATCH_GLOBAL_OBJECT_HEADER(queue_root), |
| .dq_state = DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE, |
| .do_ctxt = &_dispatch_mgr_root_queue_context, |
| .dq_label = "com.apple.root.libdispatch-manager", |
| .dq_atomic_flags = DQF_WIDTH(DISPATCH_QUEUE_WIDTH_POOL), |
| .dq_priority = DISPATCH_PRIORITY_FLAG_MANAGER | |
| DISPATCH_PRIORITY_SATURATED_OVERRIDE, |
| .dq_serialnum = 3, |
| }; |
| #endif // DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| |
| #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES || DISPATCH_USE_KEVENT_WORKQUEUE |
| static struct { |
| volatile int prio; |
| volatile qos_class_t qos; |
| int default_prio; |
| int policy; |
| #if defined(_WIN32) |
| HANDLE hThread; |
| #else |
| pthread_t tid; |
| #endif |
| } _dispatch_mgr_sched; |
| |
| static dispatch_once_t _dispatch_mgr_sched_pred; |
| |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| // TODO: switch to "event-reflector thread" property <rdar://problem/18126138> |
| // Must be kept in sync with list of qos classes in sys/qos.h |
| static const int _dispatch_mgr_sched_qos2prio[] = { |
| [QOS_CLASS_MAINTENANCE] = 4, |
| [QOS_CLASS_BACKGROUND] = 4, |
| [QOS_CLASS_UTILITY] = 20, |
| [QOS_CLASS_DEFAULT] = 31, |
| [QOS_CLASS_USER_INITIATED] = 37, |
| [QOS_CLASS_USER_INTERACTIVE] = 47, |
| }; |
| #endif // HAVE_PTHREAD_WORKQUEUE_QOS |
| |
| #if defined(_WIN32) |
| static void |
| _dispatch_mgr_sched_init(void *ctx DISPATCH_UNUSED) |
| { |
| _dispatch_mgr_sched.policy = 0; |
| _dispatch_mgr_sched.default_prio = THREAD_PRIORITY_NORMAL; |
| _dispatch_mgr_sched.prio = _dispatch_mgr_sched.default_prio; |
| } |
| #else |
| static void |
| _dispatch_mgr_sched_init(void *ctxt DISPATCH_UNUSED) |
| { |
| struct sched_param param; |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| pthread_attr_t *attr; |
| attr = &_dispatch_mgr_root_queue_pthread_context.dpq_thread_attr; |
| #else |
| pthread_attr_t a, *attr = &a; |
| #endif |
| (void)dispatch_assume_zero(pthread_attr_init(attr)); |
| (void)dispatch_assume_zero(pthread_attr_getschedpolicy(attr, |
| &_dispatch_mgr_sched.policy)); |
| (void)dispatch_assume_zero(pthread_attr_getschedparam(attr, ¶m)); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| qos_class_t qos = qos_class_main(); |
| if (qos == QOS_CLASS_DEFAULT) { |
| qos = QOS_CLASS_USER_INITIATED; // rdar://problem/17279292 |
| } |
| if (qos) { |
| _dispatch_mgr_sched.qos = qos; |
| param.sched_priority = _dispatch_mgr_sched_qos2prio[qos]; |
| } |
| #endif |
| _dispatch_mgr_sched.default_prio = param.sched_priority; |
| _dispatch_mgr_sched.prio = _dispatch_mgr_sched.default_prio; |
| } |
| #endif /* defined(_WIN32) */ |
| #endif // DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES || DISPATCH_USE_KEVENT_WORKQUEUE |
| |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| #if defined(_WIN32) |
| DISPATCH_NOINLINE |
| static PHANDLE |
| _dispatch_mgr_root_queue_init(void) |
| { |
| dispatch_once_f(&_dispatch_mgr_sched_pred, NULL, _dispatch_mgr_sched_init); |
| return &_dispatch_mgr_sched.hThread; |
| } |
| #else |
| DISPATCH_NOINLINE |
| static pthread_t * |
| _dispatch_mgr_root_queue_init(void) |
| { |
| dispatch_once_f(&_dispatch_mgr_sched_pred, NULL, _dispatch_mgr_sched_init); |
| struct sched_param param; |
| pthread_attr_t *attr; |
| attr = &_dispatch_mgr_root_queue_pthread_context.dpq_thread_attr; |
| (void)dispatch_assume_zero(pthread_attr_setdetachstate(attr, |
| PTHREAD_CREATE_DETACHED)); |
| #if !DISPATCH_DEBUG |
| (void)dispatch_assume_zero(pthread_attr_setstacksize(attr, 64 * 1024)); |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| qos_class_t qos = _dispatch_mgr_sched.qos; |
| if (qos) { |
| if (_dispatch_set_qos_class_enabled) { |
| (void)dispatch_assume_zero(pthread_attr_set_qos_class_np(attr, |
| qos, 0)); |
| } |
| } |
| #endif |
| param.sched_priority = _dispatch_mgr_sched.prio; |
| if (param.sched_priority > _dispatch_mgr_sched.default_prio) { |
| (void)dispatch_assume_zero(pthread_attr_setschedparam(attr, ¶m)); |
| } |
| return &_dispatch_mgr_sched.tid; |
| } |
| #endif |
| |
| static inline void |
| _dispatch_mgr_priority_apply(void) |
| { |
| #if defined(_WIN32) |
| int nPriority = _dispatch_mgr_sched.prio; |
| do { |
| if (nPriority > _dispatch_mgr_sched.default_prio) { |
| // TODO(compnerd) set thread scheduling policy |
| dispatch_assume_zero(SetThreadPriority(_dispatch_mgr_sched.hThread, nPriority)); |
| nPriority = GetThreadPriority(_dispatch_mgr_sched.hThread); |
| } |
| } while (_dispatch_mgr_sched.prio > nPriority); |
| #else |
| struct sched_param param; |
| do { |
| param.sched_priority = _dispatch_mgr_sched.prio; |
| if (param.sched_priority > _dispatch_mgr_sched.default_prio) { |
| (void)dispatch_assume_zero(pthread_setschedparam( |
| _dispatch_mgr_sched.tid, _dispatch_mgr_sched.policy, |
| ¶m)); |
| } |
| } while (_dispatch_mgr_sched.prio > param.sched_priority); |
| #endif |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_mgr_priority_init(void) |
| { |
| #if defined(_WIN32) |
| int nPriority = GetThreadPriority(_dispatch_mgr_sched.hThread); |
| if (slowpath(_dispatch_mgr_sched.prio > nPriority)) { |
| return _dispatch_mgr_priority_apply(); |
| } |
| #else |
| struct sched_param param; |
| pthread_attr_t *attr; |
| attr = &_dispatch_mgr_root_queue_pthread_context.dpq_thread_attr; |
| (void)dispatch_assume_zero(pthread_attr_getschedparam(attr, ¶m)); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| qos_class_t qos = 0; |
| (void)pthread_attr_get_qos_class_np(attr, &qos, NULL); |
| if (_dispatch_mgr_sched.qos > qos && _dispatch_set_qos_class_enabled) { |
| (void)pthread_set_qos_class_self_np(_dispatch_mgr_sched.qos, 0); |
| int p = _dispatch_mgr_sched_qos2prio[_dispatch_mgr_sched.qos]; |
| if (p > param.sched_priority) { |
| param.sched_priority = p; |
| } |
| } |
| #endif |
| if (slowpath(_dispatch_mgr_sched.prio > param.sched_priority)) { |
| return _dispatch_mgr_priority_apply(); |
| } |
| #endif |
| } |
| #endif // DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| |
| #if !defined(_WIN32) |
| #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_mgr_priority_raise(const pthread_attr_t *attr) |
| { |
| dispatch_once_f(&_dispatch_mgr_sched_pred, NULL, _dispatch_mgr_sched_init); |
| struct sched_param param; |
| (void)dispatch_assume_zero(pthread_attr_getschedparam(attr, ¶m)); |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| qos_class_t q, qos = 0; |
| (void)pthread_attr_get_qos_class_np((pthread_attr_t *)attr, &qos, NULL); |
| if (qos) { |
| param.sched_priority = _dispatch_mgr_sched_qos2prio[qos]; |
| os_atomic_rmw_loop2o(&_dispatch_mgr_sched, qos, q, qos, relaxed, { |
| if (q >= qos) os_atomic_rmw_loop_give_up(break); |
| }); |
| } |
| #endif |
| int p, prio = param.sched_priority; |
| os_atomic_rmw_loop2o(&_dispatch_mgr_sched, prio, p, prio, relaxed, { |
| if (p >= prio) os_atomic_rmw_loop_give_up(return); |
| }); |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| _dispatch_root_queues_init(); |
| if (_dispatch_kevent_workqueue_enabled) { |
| pthread_priority_t pp = 0; |
| if (prio > _dispatch_mgr_sched.default_prio) { |
| // The values of _PTHREAD_PRIORITY_SCHED_PRI_FLAG and |
| // _PTHREAD_PRIORITY_ROOTQUEUE_FLAG overlap, but that is not |
| // problematic in this case, since it the second one is only ever |
| // used on dq_priority fields. |
| // We never pass the _PTHREAD_PRIORITY_ROOTQUEUE_FLAG to a syscall, |
| // it is meaningful to libdispatch only. |
| pp = (pthread_priority_t)prio | _PTHREAD_PRIORITY_SCHED_PRI_FLAG; |
| } else if (qos) { |
| pp = _pthread_qos_class_encode(qos, 0, 0); |
| } |
| if (pp) { |
| int r = _pthread_workqueue_set_event_manager_priority(pp); |
| (void)dispatch_assume_zero(r); |
| } |
| return; |
| } |
| #endif |
| #if DISPATCH_USE_MGR_THREAD |
| if (_dispatch_mgr_sched.tid) { |
| return _dispatch_mgr_priority_apply(); |
| } |
| #endif |
| } |
| #endif // DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| #endif |
| |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| void |
| _dispatch_kevent_workqueue_init(void) |
| { |
| // Initialize kevent workqueue support |
| _dispatch_root_queues_init(); |
| if (!_dispatch_kevent_workqueue_enabled) return; |
| dispatch_once_f(&_dispatch_mgr_sched_pred, NULL, _dispatch_mgr_sched_init); |
| qos_class_t qos = _dispatch_mgr_sched.qos; |
| int prio = _dispatch_mgr_sched.prio; |
| pthread_priority_t pp = 0; |
| if (qos) { |
| pp = _pthread_qos_class_encode(qos, 0, 0); |
| } |
| if (prio > _dispatch_mgr_sched.default_prio) { |
| pp = (pthread_priority_t)prio | _PTHREAD_PRIORITY_SCHED_PRI_FLAG; |
| } |
| if (pp) { |
| int r = _pthread_workqueue_set_event_manager_priority(pp); |
| (void)dispatch_assume_zero(r); |
| } |
| } |
| #endif // DISPATCH_USE_KEVENT_WORKQUEUE |
| |
| #pragma mark - |
| #pragma mark dispatch_pthread_root_queue |
| |
| #if DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| static dispatch_queue_t |
| _dispatch_pthread_root_queue_create(const char *label, unsigned long flags, |
| const pthread_attr_t *attr, dispatch_block_t configure, |
| dispatch_pthread_root_queue_observer_hooks_t observer_hooks) |
| { |
| dispatch_queue_t dq; |
| dispatch_root_queue_context_t qc; |
| dispatch_pthread_root_queue_context_t pqc; |
| dispatch_queue_flags_t dqf = 0; |
| size_t dqs; |
| int32_t pool_size = flags & _DISPATCH_PTHREAD_ROOT_QUEUE_FLAG_POOL_SIZE ? |
| (int8_t)(flags & ~_DISPATCH_PTHREAD_ROOT_QUEUE_FLAG_POOL_SIZE) : 0; |
| |
| dqs = sizeof(struct dispatch_queue_s) - DISPATCH_QUEUE_CACHELINE_PAD; |
| dqs = roundup(dqs, _Alignof(struct dispatch_root_queue_context_s)); |
| dq = _dispatch_object_alloc(DISPATCH_VTABLE(queue_root), dqs + |
| sizeof(struct dispatch_root_queue_context_s) + |
| sizeof(struct dispatch_pthread_root_queue_context_s)); |
| qc = (void*)dq + dqs; |
| dispatch_assert((uintptr_t)qc % _Alignof(__typeof__(*qc)) == 0); |
| pqc = (void*)qc + sizeof(struct dispatch_root_queue_context_s); |
| dispatch_assert((uintptr_t)pqc % _Alignof(__typeof__(*pqc)) == 0); |
| if (label) { |
| const char *tmp = _dispatch_strdup_if_mutable(label); |
| if (tmp != label) { |
| dqf |= DQF_LABEL_NEEDS_FREE; |
| label = tmp; |
| } |
| } |
| |
| _dispatch_queue_init(dq, dqf, DISPATCH_QUEUE_WIDTH_POOL, 0); |
| dq->dq_label = label; |
| dq->dq_state = DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE; |
| dq->do_ctxt = qc; |
| dq->dq_priority = DISPATCH_PRIORITY_SATURATED_OVERRIDE; |
| |
| pqc->dpq_thread_mediator.do_vtable = DISPATCH_VTABLE(semaphore); |
| qc->dgq_ctxt = pqc; |
| #if DISPATCH_USE_WORKQUEUES |
| qc->dgq_kworkqueue = (void*)(~0ul); |
| #endif |
| _dispatch_root_queue_init_pthread_pool(qc, pool_size, true); |
| |
| #if defined(_WIN32) |
| dispatch_assert(attr == NULL); |
| #else |
| if (attr) { |
| memcpy(&pqc->dpq_thread_attr, attr, sizeof(pthread_attr_t)); |
| _dispatch_mgr_priority_raise(&pqc->dpq_thread_attr); |
| } else { |
| (void)dispatch_assume_zero(pthread_attr_init(&pqc->dpq_thread_attr)); |
| } |
| (void)dispatch_assume_zero(pthread_attr_setdetachstate( |
| &pqc->dpq_thread_attr, PTHREAD_CREATE_DETACHED)); |
| #endif |
| if (configure) { |
| pqc->dpq_thread_configure = _dispatch_Block_copy(configure); |
| } |
| if (observer_hooks) { |
| pqc->dpq_observer_hooks = *observer_hooks; |
| } |
| _dispatch_object_debug(dq, "%s", __func__); |
| return _dispatch_introspection_queue_create(dq); |
| } |
| |
| dispatch_queue_t |
| dispatch_pthread_root_queue_create(const char *label, unsigned long flags, |
| const pthread_attr_t *attr, dispatch_block_t configure) |
| { |
| #if defined(_WIN32) |
| dispatch_assert(attr == NULL); |
| #endif |
| return _dispatch_pthread_root_queue_create(label, flags, attr, configure, |
| NULL); |
| } |
| |
| #if DISPATCH_IOHID_SPI |
| dispatch_queue_t |
| _dispatch_pthread_root_queue_create_with_observer_hooks_4IOHID(const char *label, |
| unsigned long flags, const pthread_attr_t *attr, |
| dispatch_pthread_root_queue_observer_hooks_t observer_hooks, |
| dispatch_block_t configure) |
| { |
| if (!observer_hooks->queue_will_execute || |
| !observer_hooks->queue_did_execute) { |
| DISPATCH_CLIENT_CRASH(0, "Invalid pthread root queue observer hooks"); |
| } |
| return _dispatch_pthread_root_queue_create(label, flags, attr, configure, |
| observer_hooks); |
| } |
| #endif |
| |
| dispatch_queue_t |
| dispatch_pthread_root_queue_copy_current(void) |
| { |
| dispatch_queue_t dq = _dispatch_queue_get_current(); |
| if (!dq) return NULL; |
| while (unlikely(dq->do_targetq)) { |
| dq = dq->do_targetq; |
| } |
| if (dx_type(dq) != DISPATCH_QUEUE_GLOBAL_ROOT_TYPE || |
| dq->do_xref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT) { |
| return NULL; |
| } |
| return (dispatch_queue_t)_os_object_retain_with_resurrect(dq->_as_os_obj); |
| } |
| |
| #endif // DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| |
| void |
| _dispatch_pthread_root_queue_dispose(dispatch_queue_t dq, bool *allow_free) |
| { |
| if (slowpath(dq->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT)) { |
| DISPATCH_INTERNAL_CRASH(dq, "Global root queue disposed"); |
| } |
| _dispatch_object_debug(dq, "%s", __func__); |
| _dispatch_introspection_queue_dispose(dq); |
| #if DISPATCH_USE_PTHREAD_POOL |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| dispatch_pthread_root_queue_context_t pqc = qc->dgq_ctxt; |
| |
| #if !defined(_WIN32) |
| pthread_attr_destroy(&pqc->dpq_thread_attr); |
| #endif |
| _dispatch_semaphore_dispose(&pqc->dpq_thread_mediator, NULL); |
| if (pqc->dpq_thread_configure) { |
| Block_release(pqc->dpq_thread_configure); |
| } |
| dq->do_targetq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false); |
| #endif |
| if (dq->dq_label && _dispatch_queue_label_needs_free(dq)) { |
| free((void*)dq->dq_label); |
| } |
| _dispatch_queue_destroy(dq, allow_free); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_specific |
| |
| struct dispatch_queue_specific_queue_s { |
| DISPATCH_QUEUE_HEADER(queue_specific_queue); |
| TAILQ_HEAD(dispatch_queue_specific_head_s, |
| dispatch_queue_specific_s) dqsq_contexts; |
| } DISPATCH_ATOMIC64_ALIGN; |
| |
| struct dispatch_queue_specific_s { |
| const void *dqs_key; |
| void *dqs_ctxt; |
| dispatch_function_t dqs_destructor; |
| TAILQ_ENTRY(dispatch_queue_specific_s) dqs_list; |
| }; |
| DISPATCH_DECL(dispatch_queue_specific); |
| |
| void |
| _dispatch_queue_specific_queue_dispose(dispatch_queue_specific_queue_t dqsq, |
| bool *allow_free) |
| { |
| dispatch_queue_specific_t dqs, tmp; |
| dispatch_queue_t rq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false); |
| |
| TAILQ_FOREACH_SAFE(dqs, &dqsq->dqsq_contexts, dqs_list, tmp) { |
| if (dqs->dqs_destructor) { |
| dispatch_async_f(rq, dqs->dqs_ctxt, dqs->dqs_destructor); |
| } |
| free(dqs); |
| } |
| _dispatch_queue_destroy(dqsq->_as_dq, allow_free); |
| } |
| |
| static void |
| _dispatch_queue_init_specific(dispatch_queue_t dq) |
| { |
| dispatch_queue_specific_queue_t dqsq; |
| |
| dqsq = _dispatch_object_alloc(DISPATCH_VTABLE(queue_specific_queue), |
| sizeof(struct dispatch_queue_specific_queue_s)); |
| _dispatch_queue_init(dqsq->_as_dq, DQF_NONE, DISPATCH_QUEUE_WIDTH_MAX, |
| DISPATCH_QUEUE_ROLE_BASE_ANON); |
| dqsq->do_xref_cnt = -1; |
| dqsq->do_targetq = _dispatch_get_root_queue( |
| DISPATCH_QOS_USER_INITIATED, true); |
| dqsq->dq_label = "queue-specific"; |
| TAILQ_INIT(&dqsq->dqsq_contexts); |
| if (slowpath(!os_atomic_cmpxchg2o(dq, dq_specific_q, NULL, |
| dqsq->_as_dq, release))) { |
| _dispatch_release(dqsq->_as_dq); |
| } |
| } |
| |
| static void |
| _dispatch_queue_set_specific(void *ctxt) |
| { |
| dispatch_queue_specific_t dqs, dqsn = ctxt; |
| dispatch_queue_specific_queue_t dqsq = |
| (dispatch_queue_specific_queue_t)_dispatch_queue_get_current(); |
| |
| TAILQ_FOREACH(dqs, &dqsq->dqsq_contexts, dqs_list) { |
| if (dqs->dqs_key == dqsn->dqs_key) { |
| // Destroy previous context for existing key |
| if (dqs->dqs_destructor) { |
| dispatch_async_f(_dispatch_get_root_queue( |
| DISPATCH_QOS_DEFAULT, false), dqs->dqs_ctxt, |
| dqs->dqs_destructor); |
| } |
| if (dqsn->dqs_ctxt) { |
| // Copy new context for existing key |
| dqs->dqs_ctxt = dqsn->dqs_ctxt; |
| dqs->dqs_destructor = dqsn->dqs_destructor; |
| } else { |
| // Remove context storage for existing key |
| TAILQ_REMOVE(&dqsq->dqsq_contexts, dqs, dqs_list); |
| free(dqs); |
| } |
| return free(dqsn); |
| } |
| } |
| // Insert context storage for new key |
| TAILQ_INSERT_TAIL(&dqsq->dqsq_contexts, dqsn, dqs_list); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_queue_set_specific(dispatch_queue_t dq, const void *key, |
| void *ctxt, dispatch_function_t destructor) |
| { |
| if (slowpath(!key)) { |
| return; |
| } |
| dispatch_queue_specific_t dqs; |
| |
| dqs = _dispatch_calloc(1, sizeof(struct dispatch_queue_specific_s)); |
| dqs->dqs_key = key; |
| dqs->dqs_ctxt = ctxt; |
| dqs->dqs_destructor = destructor; |
| if (slowpath(!dq->dq_specific_q)) { |
| _dispatch_queue_init_specific(dq); |
| } |
| _dispatch_barrier_trysync_or_async_f(dq->dq_specific_q, dqs, |
| _dispatch_queue_set_specific); |
| } |
| |
| static void |
| _dispatch_queue_get_specific(void *ctxt) |
| { |
| void **ctxtp = ctxt; |
| void *key = *ctxtp; |
| dispatch_queue_specific_queue_t dqsq = |
| (dispatch_queue_specific_queue_t)_dispatch_queue_get_current(); |
| dispatch_queue_specific_t dqs; |
| |
| TAILQ_FOREACH(dqs, &dqsq->dqsq_contexts, dqs_list) { |
| if (dqs->dqs_key == key) { |
| *ctxtp = dqs->dqs_ctxt; |
| return; |
| } |
| } |
| *ctxtp = NULL; |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void * |
| _dispatch_queue_get_specific_inline(dispatch_queue_t dq, const void *key) |
| { |
| void *ctxt = NULL; |
| if (fastpath(dx_metatype(dq) == _DISPATCH_QUEUE_TYPE && dq->dq_specific_q)){ |
| ctxt = (void *)key; |
| dispatch_sync_f(dq->dq_specific_q, &ctxt, _dispatch_queue_get_specific); |
| } |
| return ctxt; |
| } |
| |
| DISPATCH_NOINLINE |
| void * |
| dispatch_queue_get_specific(dispatch_queue_t dq, const void *key) |
| { |
| if (slowpath(!key)) { |
| return NULL; |
| } |
| return _dispatch_queue_get_specific_inline(dq, key); |
| } |
| |
| DISPATCH_NOINLINE |
| void * |
| dispatch_get_specific(const void *key) |
| { |
| if (slowpath(!key)) { |
| return NULL; |
| } |
| void *ctxt = NULL; |
| dispatch_queue_t dq = _dispatch_queue_get_current(); |
| |
| while (slowpath(dq)) { |
| ctxt = _dispatch_queue_get_specific_inline(dq, key); |
| if (ctxt) break; |
| dq = dq->do_targetq; |
| } |
| return ctxt; |
| } |
| |
| #if DISPATCH_IOHID_SPI |
| bool |
| _dispatch_queue_is_exclusively_owned_by_current_thread_4IOHID( |
| dispatch_queue_t dq) // rdar://problem/18033810 |
| { |
| if (dq->dq_width != 1) { |
| DISPATCH_CLIENT_CRASH(dq->dq_width, "Invalid queue type"); |
| } |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| return _dq_state_drain_locked_by_self(dq_state); |
| } |
| #endif |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_debug |
| |
| size_t |
| _dispatch_queue_debug_attr(dispatch_queue_t dq, char* buf, size_t bufsiz) |
| { |
| size_t offset = 0; |
| dispatch_queue_t target = dq->do_targetq; |
| const char *tlabel = target && target->dq_label ? target->dq_label : ""; |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| |
| offset += dsnprintf(&buf[offset], bufsiz - offset, "sref = %d, " |
| "target = %s[%p], width = 0x%x, state = 0x%016llx", |
| dq->dq_sref_cnt + 1, tlabel, target, dq->dq_width, |
| (unsigned long long)dq_state); |
| if (_dq_state_is_suspended(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", suspended = %d", |
| _dq_state_suspend_cnt(dq_state)); |
| } |
| if (_dq_state_is_inactive(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", inactive"); |
| } else if (_dq_state_needs_activation(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", needs-activation"); |
| } |
| if (_dq_state_is_enqueued(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", enqueued"); |
| } |
| if (_dq_state_is_dirty(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", dirty"); |
| } |
| dispatch_qos_t qos = _dq_state_max_qos(dq_state); |
| if (qos) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", max qos %d", qos); |
| } |
| mach_port_t owner = _dq_state_drain_owner(dq_state); |
| if (!_dispatch_queue_is_thread_bound(dq) && owner) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", draining on 0x%x", |
| owner); |
| } |
| if (_dq_state_is_in_barrier(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", in-barrier"); |
| } else { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", in-flight = %d", |
| _dq_state_used_width(dq_state, dq->dq_width)); |
| } |
| if (_dq_state_has_pending_barrier(dq_state)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", pending-barrier"); |
| } |
| if (_dispatch_queue_is_thread_bound(dq)) { |
| offset += dsnprintf(&buf[offset], bufsiz - offset, ", thread = 0x%x ", |
| owner); |
| } |
| return offset; |
| } |
| |
| size_t |
| dispatch_queue_debug(dispatch_queue_t dq, char* buf, size_t bufsiz) |
| { |
| size_t offset = 0; |
| offset += dsnprintf(&buf[offset], bufsiz - offset, "%s[%p] = { ", |
| dq->dq_label ? dq->dq_label : dx_kind(dq), dq); |
| offset += _dispatch_object_debug_attr(dq, &buf[offset], bufsiz - offset); |
| offset += _dispatch_queue_debug_attr(dq, &buf[offset], bufsiz - offset); |
| offset += dsnprintf(&buf[offset], bufsiz - offset, "}"); |
| return offset; |
| } |
| |
| #if DISPATCH_DEBUG |
| void |
| dispatch_debug_queue(dispatch_queue_t dq, const char* str) { |
| if (fastpath(dq)) { |
| _dispatch_object_debug(dq, "%s", str); |
| } else { |
| _dispatch_log("queue[NULL]: %s", str); |
| } |
| } |
| #endif |
| |
| #if DISPATCH_PERF_MON |
| |
| #define DISPATCH_PERF_MON_BUCKETS 8 |
| |
| static struct { |
| uint64_t volatile time_total; |
| uint64_t volatile count_total; |
| uint64_t volatile thread_total; |
| } _dispatch_stats[DISPATCH_PERF_MON_BUCKETS]; |
| DISPATCH_USED static size_t _dispatch_stat_buckets = DISPATCH_PERF_MON_BUCKETS; |
| |
| void |
| _dispatch_queue_merge_stats(uint64_t start, bool trace, perfmon_thread_type type) |
| { |
| uint64_t delta = _dispatch_absolute_time() - start; |
| unsigned long count; |
| int bucket = 0; |
| count = (unsigned long)_dispatch_thread_getspecific(dispatch_bcounter_key); |
| _dispatch_thread_setspecific(dispatch_bcounter_key, NULL); |
| if (count == 0) { |
| bucket = 0; |
| if (trace) _dispatch_ktrace1(DISPATCH_PERF_MON_worker_useless, type); |
| } else { |
| bucket = MIN(DISPATCH_PERF_MON_BUCKETS - 1, |
| (int)sizeof(count) * CHAR_BIT - __builtin_clzl(count)); |
| os_atomic_add(&_dispatch_stats[bucket].count_total, count, relaxed); |
| } |
| os_atomic_add(&_dispatch_stats[bucket].time_total, delta, relaxed); |
| os_atomic_inc(&_dispatch_stats[bucket].thread_total, relaxed); |
| if (trace) { |
| _dispatch_ktrace3(DISPATCH_PERF_MON_worker_thread_end, count, delta, type); |
| } |
| } |
| |
| #endif |
| |
| #pragma mark - |
| #pragma mark _dispatch_set_priority_and_mach_voucher |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_set_priority_and_mach_voucher_slow(pthread_priority_t pp, |
| mach_voucher_t kv) |
| { |
| _pthread_set_flags_t pflags = 0; |
| if (pp && _dispatch_set_qos_class_enabled) { |
| pthread_priority_t old_pri = _dispatch_get_priority(); |
| if (pp != old_pri) { |
| if (old_pri & _PTHREAD_PRIORITY_NEEDS_UNBIND_FLAG) { |
| pflags |= _PTHREAD_SET_SELF_WQ_KEVENT_UNBIND; |
| // when we unbind, overcomitness can flip, so we need to learn |
| // it from the defaultpri, see _dispatch_priority_compute_update |
| pp |= (_dispatch_get_basepri() & |
| DISPATCH_PRIORITY_FLAG_OVERCOMMIT); |
| } else { |
| // else we need to keep the one that is set in the current pri |
| pp |= (old_pri & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG); |
| } |
| if (likely(old_pri & ~_PTHREAD_PRIORITY_FLAGS_MASK)) { |
| pflags |= _PTHREAD_SET_SELF_QOS_FLAG; |
| } |
| uint64_t mgr_dq_state = |
| os_atomic_load2o(&_dispatch_mgr_q, dq_state, relaxed); |
| if (unlikely(_dq_state_drain_locked_by_self(mgr_dq_state))) { |
| DISPATCH_INTERNAL_CRASH(pp, |
| "Changing the QoS while on the manager queue"); |
| } |
| if (unlikely(pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG)) { |
| DISPATCH_INTERNAL_CRASH(pp, "Cannot raise oneself to manager"); |
| } |
| if (old_pri & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) { |
| DISPATCH_INTERNAL_CRASH(old_pri, |
| "Cannot turn a manager thread into a normal one"); |
| } |
| } |
| } |
| if (kv != VOUCHER_NO_MACH_VOUCHER) { |
| #if VOUCHER_USE_MACH_VOUCHER |
| pflags |= _PTHREAD_SET_SELF_VOUCHER_FLAG; |
| #endif |
| } |
| if (!pflags) return; |
| int r = _pthread_set_properties_self(pflags, pp, kv); |
| if (r == EINVAL) { |
| DISPATCH_INTERNAL_CRASH(pp, "_pthread_set_properties_self failed"); |
| } |
| (void)dispatch_assume_zero(r); |
| } |
| |
| DISPATCH_NOINLINE |
| voucher_t |
| _dispatch_set_priority_and_voucher_slow(pthread_priority_t priority, |
| voucher_t v, dispatch_thread_set_self_t flags) |
| { |
| voucher_t ov = DISPATCH_NO_VOUCHER; |
| mach_voucher_t kv = VOUCHER_NO_MACH_VOUCHER; |
| if (v != DISPATCH_NO_VOUCHER) { |
| bool retained = flags & DISPATCH_VOUCHER_CONSUME; |
| ov = _voucher_get(); |
| if (ov == v && (flags & DISPATCH_VOUCHER_REPLACE)) { |
| if (retained && v) _voucher_release_no_dispose(v); |
| ov = DISPATCH_NO_VOUCHER; |
| } else { |
| if (!retained && v) _voucher_retain(v); |
| kv = _voucher_swap_and_get_mach_voucher(ov, v); |
| } |
| } |
| if (!(flags & DISPATCH_THREAD_PARK)) { |
| _dispatch_set_priority_and_mach_voucher_slow(priority, kv); |
| } |
| if (ov != DISPATCH_NO_VOUCHER && (flags & DISPATCH_VOUCHER_REPLACE)) { |
| if (ov) _voucher_release(ov); |
| ov = DISPATCH_NO_VOUCHER; |
| } |
| return ov; |
| } |
| #endif |
| #pragma mark - |
| #pragma mark dispatch_continuation_t |
| |
| const struct dispatch_continuation_vtable_s _dispatch_continuation_vtables[] = { |
| DC_VTABLE_ENTRY(ASYNC_REDIRECT, |
| .do_kind = "dc-redirect", |
| .do_invoke = _dispatch_async_redirect_invoke), |
| #if HAVE_MACH |
| DC_VTABLE_ENTRY(MACH_SEND_BARRRIER_DRAIN, |
| .do_kind = "dc-mach-send-drain", |
| .do_invoke = _dispatch_mach_send_barrier_drain_invoke), |
| DC_VTABLE_ENTRY(MACH_SEND_BARRIER, |
| .do_kind = "dc-mach-send-barrier", |
| .do_invoke = _dispatch_mach_barrier_invoke), |
| DC_VTABLE_ENTRY(MACH_RECV_BARRIER, |
| .do_kind = "dc-mach-recv-barrier", |
| .do_invoke = _dispatch_mach_barrier_invoke), |
| DC_VTABLE_ENTRY(MACH_ASYNC_REPLY, |
| .do_kind = "dc-mach-async-reply", |
| .do_invoke = _dispatch_mach_msg_async_reply_invoke), |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| DC_VTABLE_ENTRY(OVERRIDE_STEALING, |
| .do_kind = "dc-override-stealing", |
| .do_invoke = _dispatch_queue_override_invoke), |
| DC_VTABLE_ENTRY(OVERRIDE_OWNING, |
| .do_kind = "dc-override-owning", |
| .do_invoke = _dispatch_queue_override_invoke), |
| #endif |
| }; |
| |
| static void |
| _dispatch_force_cache_cleanup(void) |
| { |
| dispatch_continuation_t dc; |
| dc = _dispatch_thread_getspecific(dispatch_cache_key); |
| if (dc) { |
| _dispatch_thread_setspecific(dispatch_cache_key, NULL); |
| _dispatch_cache_cleanup(dc); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| static void DISPATCH_TSD_DTOR_CC |
| _dispatch_cache_cleanup(void *value) |
| { |
| dispatch_continuation_t dc, next_dc = value; |
| |
| while ((dc = next_dc)) { |
| next_dc = dc->do_next; |
| _dispatch_continuation_free_to_heap(dc); |
| } |
| } |
| |
| #if DISPATCH_USE_MEMORYPRESSURE_SOURCE |
| DISPATCH_NOINLINE |
| void |
| _dispatch_continuation_free_to_cache_limit(dispatch_continuation_t dc) |
| { |
| _dispatch_continuation_free_to_heap(dc); |
| dispatch_continuation_t next_dc; |
| dc = _dispatch_thread_getspecific(dispatch_cache_key); |
| int cnt; |
| if (!dc || (cnt = dc->dc_cache_cnt - |
| _dispatch_continuation_cache_limit) <= 0) { |
| return; |
| } |
| do { |
| next_dc = dc->do_next; |
| _dispatch_continuation_free_to_heap(dc); |
| } while (--cnt && (dc = next_dc)); |
| _dispatch_thread_setspecific(dispatch_cache_key, next_dc); |
| } |
| #endif |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_continuation_push(dispatch_queue_t dq, dispatch_continuation_t dc) |
| { |
| dx_push(dq, dc, _dispatch_continuation_override_qos(dq, dc)); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_continuation_async2(dispatch_queue_t dq, dispatch_continuation_t dc, |
| bool barrier) |
| { |
| if (fastpath(barrier || !DISPATCH_QUEUE_USES_REDIRECTION(dq->dq_width))) { |
| return _dispatch_continuation_push(dq, dc); |
| } |
| return _dispatch_async_f2(dq, dc); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_continuation_async(dispatch_queue_t dq, dispatch_continuation_t dc) |
| { |
| _dispatch_continuation_async2(dq, dc, |
| dc->dc_flags & DISPATCH_OBJ_BARRIER_BIT); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_block_create |
| |
| #if __BLOCKS__ |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_block_flags_valid(dispatch_block_flags_t flags) |
| { |
| return ((flags & ~DISPATCH_BLOCK_API_MASK) == 0); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_block_flags_t |
| _dispatch_block_normalize_flags(dispatch_block_flags_t flags) |
| { |
| if (flags & (DISPATCH_BLOCK_NO_VOUCHER|DISPATCH_BLOCK_DETACHED)) { |
| flags |= DISPATCH_BLOCK_HAS_VOUCHER; |
| } |
| if (flags & (DISPATCH_BLOCK_NO_QOS_CLASS|DISPATCH_BLOCK_DETACHED)) { |
| flags |= DISPATCH_BLOCK_HAS_PRIORITY; |
| } |
| return flags; |
| } |
| |
| static inline dispatch_block_t |
| _dispatch_block_create_with_voucher_and_priority(dispatch_block_flags_t flags, |
| voucher_t voucher, pthread_priority_t pri, dispatch_block_t block) |
| { |
| flags = _dispatch_block_normalize_flags(flags); |
| bool assign = (flags & DISPATCH_BLOCK_ASSIGN_CURRENT); |
| |
| if (assign && !(flags & DISPATCH_BLOCK_HAS_VOUCHER)) { |
| #if OS_VOUCHER_ACTIVITY_SPI |
| voucher = VOUCHER_CURRENT; |
| #endif |
| flags |= DISPATCH_BLOCK_HAS_VOUCHER; |
| } |
| #if OS_VOUCHER_ACTIVITY_SPI |
| if (voucher == VOUCHER_CURRENT) { |
| voucher = _voucher_get(); |
| } |
| #endif |
| if (assign && !(flags & DISPATCH_BLOCK_HAS_PRIORITY)) { |
| pri = _dispatch_priority_propagate(); |
| flags |= DISPATCH_BLOCK_HAS_PRIORITY; |
| } |
| dispatch_block_t db = _dispatch_block_create(flags, voucher, pri, block); |
| #if DISPATCH_DEBUG |
| dispatch_assert(_dispatch_block_get_data(db)); |
| #endif |
| return db; |
| } |
| |
| dispatch_block_t |
| dispatch_block_create(dispatch_block_flags_t flags, dispatch_block_t block) |
| { |
| if (!_dispatch_block_flags_valid(flags)) return DISPATCH_BAD_INPUT; |
| return _dispatch_block_create_with_voucher_and_priority(flags, NULL, 0, |
| block); |
| } |
| |
| dispatch_block_t |
| dispatch_block_create_with_qos_class(dispatch_block_flags_t flags, |
| dispatch_qos_class_t qos_class, int relative_priority, |
| dispatch_block_t block) |
| { |
| if (!_dispatch_block_flags_valid(flags) || |
| !_dispatch_qos_class_valid(qos_class, relative_priority)) { |
| return DISPATCH_BAD_INPUT; |
| } |
| flags |= DISPATCH_BLOCK_HAS_PRIORITY; |
| pthread_priority_t pri = 0; |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| pri = _pthread_qos_class_encode(qos_class, relative_priority, 0); |
| #endif |
| return _dispatch_block_create_with_voucher_and_priority(flags, NULL, |
| pri, block); |
| } |
| |
| dispatch_block_t |
| dispatch_block_create_with_voucher(dispatch_block_flags_t flags, |
| voucher_t voucher, dispatch_block_t block) |
| { |
| if (!_dispatch_block_flags_valid(flags)) return DISPATCH_BAD_INPUT; |
| flags |= DISPATCH_BLOCK_HAS_VOUCHER; |
| return _dispatch_block_create_with_voucher_and_priority(flags, voucher, 0, |
| block); |
| } |
| |
| dispatch_block_t |
| dispatch_block_create_with_voucher_and_qos_class(dispatch_block_flags_t flags, |
| voucher_t voucher, dispatch_qos_class_t qos_class, |
| int relative_priority, dispatch_block_t block) |
| { |
| if (!_dispatch_block_flags_valid(flags) || |
| !_dispatch_qos_class_valid(qos_class, relative_priority)) { |
| return DISPATCH_BAD_INPUT; |
| } |
| flags |= (DISPATCH_BLOCK_HAS_VOUCHER|DISPATCH_BLOCK_HAS_PRIORITY); |
| pthread_priority_t pri = 0; |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| pri = _pthread_qos_class_encode(qos_class, relative_priority, 0); |
| #endif |
| return _dispatch_block_create_with_voucher_and_priority(flags, voucher, |
| pri, block); |
| } |
| |
| void |
| dispatch_block_perform(dispatch_block_flags_t flags, dispatch_block_t block) |
| { |
| if (!_dispatch_block_flags_valid(flags)) { |
| DISPATCH_CLIENT_CRASH(flags, "Invalid flags passed to " |
| "dispatch_block_perform()"); |
| } |
| flags = _dispatch_block_normalize_flags(flags); |
| struct dispatch_block_private_data_s dbpds = |
| DISPATCH_BLOCK_PRIVATE_DATA_PERFORM_INITIALIZER(flags, block); |
| return _dispatch_block_invoke_direct(&dbpds); |
| } |
| |
| #define _dbpd_group(dbpd) ((dbpd)->dbpd_group) |
| |
| void |
| _dispatch_block_invoke_direct(const struct dispatch_block_private_data_s *dbcpd) |
| { |
| dispatch_block_private_data_t dbpd = (dispatch_block_private_data_t)dbcpd; |
| dispatch_block_flags_t flags = dbpd->dbpd_flags; |
| unsigned int atomic_flags = dbpd->dbpd_atomic_flags; |
| if (slowpath(atomic_flags & DBF_WAITED)) { |
| DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both " |
| "run more than once and waited for"); |
| } |
| if (atomic_flags & DBF_CANCELED) goto out; |
| |
| pthread_priority_t op = 0, p = 0; |
| op = _dispatch_block_invoke_should_set_priority(flags, dbpd->dbpd_priority); |
| if (op) { |
| p = dbpd->dbpd_priority; |
| } |
| voucher_t ov, v = DISPATCH_NO_VOUCHER; |
| if (flags & DISPATCH_BLOCK_HAS_VOUCHER) { |
| v = dbpd->dbpd_voucher; |
| } |
| ov = _dispatch_set_priority_and_voucher(p, v, 0); |
| dbpd->dbpd_thread = _dispatch_tid_self(); |
| _dispatch_client_callout(dbpd->dbpd_block, |
| _dispatch_Block_invoke(dbpd->dbpd_block)); |
| _dispatch_reset_priority_and_voucher(op, ov); |
| out: |
| if ((atomic_flags & DBF_PERFORM) == 0) { |
| if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) { |
| dispatch_group_leave(_dbpd_group(dbpd)); |
| } |
| } |
| } |
| |
| void |
| _dispatch_block_sync_invoke(void *block) |
| { |
| dispatch_block_t b = block; |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(b); |
| dispatch_block_flags_t flags = dbpd->dbpd_flags; |
| unsigned int atomic_flags = dbpd->dbpd_atomic_flags; |
| if (unlikely(atomic_flags & DBF_WAITED)) { |
| DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both " |
| "run more than once and waited for"); |
| } |
| if (atomic_flags & DBF_CANCELED) goto out; |
| |
| voucher_t ov = DISPATCH_NO_VOUCHER; |
| if (flags & DISPATCH_BLOCK_HAS_VOUCHER) { |
| ov = _dispatch_adopt_priority_and_set_voucher(0, dbpd->dbpd_voucher, 0); |
| } |
| dbpd->dbpd_block(); |
| _dispatch_reset_voucher(ov, 0); |
| out: |
| if ((atomic_flags & DBF_PERFORM) == 0) { |
| if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) { |
| dispatch_group_leave(_dbpd_group(dbpd)); |
| } |
| } |
| |
| os_mpsc_queue_t oq; |
| oq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed); |
| if (oq) { |
| // balances dispatch_{,barrier_,}sync |
| _os_object_release_internal_n(oq->_as_os_obj, 2); |
| } |
| } |
| |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| static void |
| _dispatch_block_async_invoke_reset_max_qos(dispatch_queue_t dq, |
| dispatch_qos_t qos) |
| { |
| uint64_t old_state, new_state, qos_bits = _dq_state_from_qos(qos); |
| |
| // Only dispatch queues can reach this point (as opposed to sources or more |
| // complex objects) which allows us to handle the DIRTY bit protocol by only |
| // looking at the tail |
| dispatch_assert(dx_metatype(dq) == _DISPATCH_QUEUE_TYPE); |
| |
| again: |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| dispatch_assert(_dq_state_is_base_wlh(old_state)); |
| if ((old_state & DISPATCH_QUEUE_MAX_QOS_MASK) <= qos_bits) { |
| // Nothing to do if the QoS isn't going down |
| os_atomic_rmw_loop_give_up(return); |
| } |
| if (_dq_state_is_dirty(old_state)) { |
| os_atomic_rmw_loop_give_up({ |
| // just renew the drain lock with an acquire barrier, to see |
| // what the enqueuer that set DIRTY has done. |
| // the xor generates better assembly as DISPATCH_QUEUE_DIRTY |
| // is already in a register |
| os_atomic_xor2o(dq, dq_state, DISPATCH_QUEUE_DIRTY, acquire); |
| if (!dq->dq_items_tail) { |
| goto again; |
| } |
| return; |
| }); |
| } |
| |
| new_state = old_state; |
| new_state &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| new_state |= qos_bits; |
| }); |
| |
| _dispatch_deferred_items_get()->ddi_wlh_needs_update = true; |
| _dispatch_event_loop_drain(KEVENT_FLAG_IMMEDIATE); |
| } |
| #endif // DISPATCH_USE_KEVENT_WORKQUEUE |
| |
| #define DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE 0x1 |
| #define DISPATCH_BLOCK_ASYNC_INVOKE_NO_OVERRIDE_RESET 0x2 |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_block_async_invoke2(dispatch_block_t b, unsigned long invoke_flags) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(b); |
| unsigned int atomic_flags = dbpd->dbpd_atomic_flags; |
| if (slowpath(atomic_flags & DBF_WAITED)) { |
| DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both " |
| "run more than once and waited for"); |
| } |
| |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| if (unlikely((dbpd->dbpd_flags & |
| DISPATCH_BLOCK_IF_LAST_RESET_QUEUE_QOS_OVERRIDE) && |
| !(invoke_flags & DISPATCH_BLOCK_ASYNC_INVOKE_NO_OVERRIDE_RESET))) { |
| dispatch_queue_t dq = _dispatch_get_current_queue(); |
| dispatch_qos_t qos = _dispatch_qos_from_pp(_dispatch_get_priority()); |
| if ((dispatch_wlh_t)dq == _dispatch_get_wlh() && !dq->dq_items_tail) { |
| _dispatch_block_async_invoke_reset_max_qos(dq, qos); |
| } |
| } |
| #endif // DISPATCH_USE_KEVENT_WORKQUEUE |
| |
| if (!slowpath(atomic_flags & DBF_CANCELED)) { |
| dbpd->dbpd_block(); |
| } |
| if ((atomic_flags & DBF_PERFORM) == 0) { |
| if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) { |
| dispatch_group_leave(_dbpd_group(dbpd)); |
| } |
| } |
| |
| os_mpsc_queue_t oq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed); |
| if (oq) { |
| // balances dispatch_{,barrier_,group_}async |
| _os_object_release_internal_n_inline(oq->_as_os_obj, 2); |
| } |
| |
| if (invoke_flags & DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE) { |
| Block_release(b); |
| } |
| } |
| |
| static void |
| _dispatch_block_async_invoke(void *block) |
| { |
| _dispatch_block_async_invoke2(block, 0); |
| } |
| |
| static void |
| _dispatch_block_async_invoke_and_release(void *block) |
| { |
| _dispatch_block_async_invoke2(block, DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE); |
| } |
| |
| static void |
| _dispatch_block_async_invoke_and_release_mach_barrier(void *block) |
| { |
| _dispatch_block_async_invoke2(block, DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE | |
| DISPATCH_BLOCK_ASYNC_INVOKE_NO_OVERRIDE_RESET); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_block_supports_wait_and_cancel(dispatch_block_private_data_t dbpd) |
| { |
| return dbpd && !(dbpd->dbpd_flags & |
| DISPATCH_BLOCK_IF_LAST_RESET_QUEUE_QOS_OVERRIDE); |
| } |
| |
| void |
| dispatch_block_cancel(dispatch_block_t db) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db); |
| if (unlikely(!_dispatch_block_supports_wait_and_cancel(dbpd))) { |
| DISPATCH_CLIENT_CRASH(db, "Invalid block object passed to " |
| "dispatch_block_cancel()"); |
| } |
| (void)os_atomic_or2o(dbpd, dbpd_atomic_flags, DBF_CANCELED, relaxed); |
| } |
| |
| long |
| dispatch_block_testcancel(dispatch_block_t db) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db); |
| if (unlikely(!_dispatch_block_supports_wait_and_cancel(dbpd))) { |
| DISPATCH_CLIENT_CRASH(db, "Invalid block object passed to " |
| "dispatch_block_testcancel()"); |
| } |
| return (bool)(dbpd->dbpd_atomic_flags & DBF_CANCELED); |
| } |
| |
| long |
| dispatch_block_wait(dispatch_block_t db, dispatch_time_t timeout) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db); |
| if (unlikely(!_dispatch_block_supports_wait_and_cancel(dbpd))) { |
| DISPATCH_CLIENT_CRASH(db, "Invalid block object passed to " |
| "dispatch_block_wait()"); |
| } |
| |
| unsigned int flags = os_atomic_or_orig2o(dbpd, dbpd_atomic_flags, |
| DBF_WAITING, relaxed); |
| if (slowpath(flags & (DBF_WAITED | DBF_WAITING))) { |
| DISPATCH_CLIENT_CRASH(flags, "A block object may not be waited for " |
| "more than once"); |
| } |
| |
| // <rdar://problem/17703192> If we know the queue where this block is |
| // enqueued, or the thread that's executing it, then we should boost |
| // it here. |
| |
| pthread_priority_t pp = _dispatch_get_priority(); |
| |
| os_mpsc_queue_t boost_oq; |
| boost_oq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed); |
| if (boost_oq) { |
| // release balances dispatch_{,barrier_,group_}async. |
| // Can't put the queue back in the timeout case: the block might |
| // finish after we fell out of group_wait and see our NULL, so |
| // neither of us would ever release. Side effect: After a _wait |
| // that times out, subsequent waits will not boost the qos of the |
| // still-running block. |
| dx_wakeup(boost_oq, _dispatch_qos_from_pp(pp), |
| DISPATCH_WAKEUP_BLOCK_WAIT | DISPATCH_WAKEUP_CONSUME_2); |
| } |
| |
| mach_port_t boost_th = dbpd->dbpd_thread; |
| if (boost_th) { |
| _dispatch_thread_override_start(boost_th, pp, dbpd); |
| } |
| |
| int performed = os_atomic_load2o(dbpd, dbpd_performed, relaxed); |
| if (slowpath(performed > 1 || (boost_th && boost_oq))) { |
| DISPATCH_CLIENT_CRASH(performed, "A block object may not be both " |
| "run more than once and waited for"); |
| } |
| |
| long ret = dispatch_group_wait(_dbpd_group(dbpd), timeout); |
| |
| if (boost_th) { |
| _dispatch_thread_override_end(boost_th, dbpd); |
| } |
| |
| if (ret) { |
| // timed out: reverse our changes |
| (void)os_atomic_and2o(dbpd, dbpd_atomic_flags, |
| ~DBF_WAITING, relaxed); |
| } else { |
| (void)os_atomic_or2o(dbpd, dbpd_atomic_flags, |
| DBF_WAITED, relaxed); |
| // don't need to re-test here: the second call would see |
| // the first call's WAITING |
| } |
| |
| return ret; |
| } |
| |
| void |
| dispatch_block_notify(dispatch_block_t db, dispatch_queue_t queue, |
| dispatch_block_t notification_block) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db); |
| if (!dbpd) { |
| DISPATCH_CLIENT_CRASH(db, "Invalid block object passed to " |
| "dispatch_block_notify()"); |
| } |
| int performed = os_atomic_load2o(dbpd, dbpd_performed, relaxed); |
| if (slowpath(performed > 1)) { |
| DISPATCH_CLIENT_CRASH(performed, "A block object may not be both " |
| "run more than once and observed"); |
| } |
| |
| return dispatch_group_notify(_dbpd_group(dbpd), queue, notification_block); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_continuation_init_slow(dispatch_continuation_t dc, |
| dispatch_queue_class_t dqu, dispatch_block_flags_t flags) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(dc->dc_ctxt); |
| dispatch_block_flags_t block_flags = dbpd->dbpd_flags; |
| uintptr_t dc_flags = dc->dc_flags; |
| os_mpsc_queue_t oq = dqu._oq; |
| |
| // balanced in d_block_async_invoke_and_release or d_block_wait |
| if (os_atomic_cmpxchg2o(dbpd, dbpd_queue, NULL, oq, relaxed)) { |
| _os_object_retain_internal_n_inline(oq->_as_os_obj, 2); |
| } |
| |
| if (dc_flags & DISPATCH_OBJ_MACH_BARRIER) { |
| dispatch_assert(dc_flags & DISPATCH_OBJ_CONSUME_BIT); |
| dc->dc_func = _dispatch_block_async_invoke_and_release_mach_barrier; |
| } else if (dc_flags & DISPATCH_OBJ_CONSUME_BIT) { |
| dc->dc_func = _dispatch_block_async_invoke_and_release; |
| } else { |
| dc->dc_func = _dispatch_block_async_invoke; |
| } |
| |
| flags |= block_flags; |
| if (block_flags & DISPATCH_BLOCK_HAS_PRIORITY) { |
| _dispatch_continuation_priority_set(dc, dbpd->dbpd_priority, flags); |
| } else { |
| _dispatch_continuation_priority_set(dc, dc->dc_priority, flags); |
| } |
| if (block_flags & DISPATCH_BLOCK_BARRIER) { |
| dc_flags |= DISPATCH_OBJ_BARRIER_BIT; |
| } |
| if (block_flags & DISPATCH_BLOCK_HAS_VOUCHER) { |
| voucher_t v = dbpd->dbpd_voucher; |
| dc->dc_voucher = v ? _voucher_retain(v) : NULL; |
| dc_flags |= DISPATCH_OBJ_ENFORCE_VOUCHER; |
| _dispatch_voucher_debug("continuation[%p] set", dc->dc_voucher, dc); |
| _dispatch_voucher_ktrace_dc_push(dc); |
| } else { |
| _dispatch_continuation_voucher_set(dc, oq, flags); |
| } |
| dc_flags |= DISPATCH_OBJ_BLOCK_PRIVATE_DATA_BIT; |
| dc->dc_flags = dc_flags; |
| } |
| |
| #endif // __BLOCKS__ |
| #pragma mark - |
| #pragma mark dispatch_barrier_async |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_async_f_slow(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func, pthread_priority_t pp, |
| dispatch_block_flags_t flags, uintptr_t dc_flags) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc_from_heap(); |
| _dispatch_continuation_init_f(dc, dq, ctxt, func, pp, flags, dc_flags); |
| _dispatch_continuation_async(dq, dc); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_barrier_async_f2(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func, pthread_priority_t pp, |
| dispatch_block_flags_t flags) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc_cacheonly(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT | DISPATCH_OBJ_BARRIER_BIT; |
| |
| if (!fastpath(dc)) { |
| return _dispatch_async_f_slow(dq, ctxt, func, pp, flags, dc_flags); |
| } |
| |
| _dispatch_continuation_init_f(dc, dq, ctxt, func, pp, flags, dc_flags); |
| _dispatch_continuation_push(dq, dc); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| _dispatch_barrier_async_f2(dq, ctxt, func, 0, 0); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_barrier_async_detached_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| dc->dc_flags = DISPATCH_OBJ_CONSUME_BIT | DISPATCH_OBJ_BARRIER_BIT; |
| dc->dc_func = func; |
| dc->dc_ctxt = ctxt; |
| dc->dc_voucher = DISPATCH_NO_VOUCHER; |
| dc->dc_priority = DISPATCH_NO_PRIORITY; |
| dx_push(dq, dc, 0); |
| } |
| |
| #ifdef __BLOCKS__ |
| void |
| dispatch_barrier_async(dispatch_queue_t dq, dispatch_block_t work) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT | DISPATCH_OBJ_BARRIER_BIT; |
| |
| _dispatch_continuation_init(dc, dq, work, 0, 0, dc_flags); |
| _dispatch_continuation_push(dq, dc); |
| } |
| #endif |
| |
| #pragma mark - |
| #pragma mark dispatch_async |
| |
| void |
| _dispatch_async_redirect_invoke(dispatch_continuation_t dc, |
| dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags) |
| { |
| dispatch_thread_frame_s dtf; |
| struct dispatch_continuation_s *other_dc = dc->dc_other; |
| dispatch_invoke_flags_t ctxt_flags = (dispatch_invoke_flags_t)dc->dc_ctxt; |
| // if we went through _dispatch_root_queue_push_override, |
| // the "right" root queue was stuffed into dc_func |
| dispatch_queue_t assumed_rq = (dispatch_queue_t)dc->dc_func; |
| dispatch_queue_t dq = dc->dc_data, rq, old_dq; |
| dispatch_priority_t old_dbp; |
| |
| if (ctxt_flags) { |
| flags &= ~_DISPATCH_INVOKE_AUTORELEASE_MASK; |
| flags |= ctxt_flags; |
| } |
| old_dq = _dispatch_get_current_queue(); |
| if (assumed_rq) { |
| old_dbp = _dispatch_root_queue_identity_assume(assumed_rq); |
| _dispatch_set_basepri(dq->dq_priority); |
| } else { |
| old_dbp = _dispatch_set_basepri(dq->dq_priority); |
| } |
| |
| _dispatch_thread_frame_push(&dtf, dq); |
| _dispatch_continuation_pop_forwarded(dc, DISPATCH_NO_VOUCHER, |
| DISPATCH_OBJ_CONSUME_BIT, { |
| _dispatch_continuation_pop(other_dc, dic, flags, dq); |
| }); |
| _dispatch_thread_frame_pop(&dtf); |
| if (assumed_rq) _dispatch_queue_set_current(old_dq); |
| _dispatch_reset_basepri(old_dbp); |
| |
| rq = dq->do_targetq; |
| while (slowpath(rq->do_targetq) && rq != old_dq) { |
| _dispatch_queue_non_barrier_complete(rq); |
| rq = rq->do_targetq; |
| } |
| |
| _dispatch_queue_non_barrier_complete(dq); |
| _dispatch_release_tailcall(dq); // pairs with _dispatch_async_redirect_wrap |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_continuation_t |
| _dispatch_async_redirect_wrap(dispatch_queue_t dq, dispatch_object_t dou) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| |
| dou._do->do_next = NULL; |
| dc->do_vtable = DC_VTABLE(ASYNC_REDIRECT); |
| dc->dc_func = NULL; |
| dc->dc_ctxt = (void *)(uintptr_t)_dispatch_queue_autorelease_frequency(dq); |
| dc->dc_data = dq; |
| dc->dc_other = dou._do; |
| dc->dc_voucher = DISPATCH_NO_VOUCHER; |
| dc->dc_priority = DISPATCH_NO_PRIORITY; |
| _dispatch_retain(dq); // released in _dispatch_async_redirect_invoke |
| return dc; |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_async_f_redirect(dispatch_queue_t dq, |
| dispatch_object_t dou, dispatch_qos_t qos) |
| { |
| if (!slowpath(_dispatch_object_is_redirection(dou))) { |
| dou._dc = _dispatch_async_redirect_wrap(dq, dou); |
| } |
| dq = dq->do_targetq; |
| |
| // Find the queue to redirect to |
| while (slowpath(DISPATCH_QUEUE_USES_REDIRECTION(dq->dq_width))) { |
| if (!fastpath(_dispatch_queue_try_acquire_async(dq))) { |
| break; |
| } |
| if (!dou._dc->dc_ctxt) { |
| // find first queue in descending target queue order that has |
| // an autorelease frequency set, and use that as the frequency for |
| // this continuation. |
| dou._dc->dc_ctxt = (void *) |
| (uintptr_t)_dispatch_queue_autorelease_frequency(dq); |
| } |
| dq = dq->do_targetq; |
| } |
| |
| dx_push(dq, dou, qos); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_continuation_redirect(dispatch_queue_t dq, |
| struct dispatch_object_s *dc) |
| { |
| _dispatch_trace_continuation_pop(dq, dc); |
| // This is a re-redirect, overrides have already been applied |
| // by _dispatch_async_f2. |
| // However we want to end up on the root queue matching `dc` qos, so pick up |
| // the current override of `dq` which includes dc's overrde (and maybe more) |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| _dispatch_async_f_redirect(dq, dc, _dq_state_max_qos(dq_state)); |
| _dispatch_introspection_queue_item_complete(dc); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_async_f2(dispatch_queue_t dq, dispatch_continuation_t dc) |
| { |
| // <rdar://problem/24738102&24743140> reserving non barrier width |
| // doesn't fail if only the ENQUEUED bit is set (unlike its barrier width |
| // equivalent), so we have to check that this thread hasn't enqueued |
| // anything ahead of this call or we can break ordering |
| if (slowpath(dq->dq_items_tail)) { |
| return _dispatch_continuation_push(dq, dc); |
| } |
| |
| if (slowpath(!_dispatch_queue_try_acquire_async(dq))) { |
| return _dispatch_continuation_push(dq, dc); |
| } |
| |
| return _dispatch_async_f_redirect(dq, dc, |
| _dispatch_continuation_override_qos(dq, dc)); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_async_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t func, |
| pthread_priority_t pp, dispatch_block_flags_t flags) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc_cacheonly(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT; |
| |
| if (!fastpath(dc)) { |
| return _dispatch_async_f_slow(dq, ctxt, func, pp, flags, dc_flags); |
| } |
| |
| _dispatch_continuation_init_f(dc, dq, ctxt, func, pp, flags, dc_flags); |
| _dispatch_continuation_async2(dq, dc, false); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_async_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t func) |
| { |
| _dispatch_async_f(dq, ctxt, func, 0, 0); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_async_enforce_qos_class_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| _dispatch_async_f(dq, ctxt, func, 0, DISPATCH_BLOCK_ENFORCE_QOS_CLASS); |
| } |
| |
| #ifdef __BLOCKS__ |
| void |
| dispatch_async(dispatch_queue_t dq, dispatch_block_t work) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT; |
| |
| _dispatch_continuation_init(dc, dq, work, 0, 0, dc_flags); |
| _dispatch_continuation_async(dq, dc); |
| } |
| #endif |
| |
| #pragma mark - |
| #pragma mark dispatch_group_async |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_continuation_group_async(dispatch_group_t dg, dispatch_queue_t dq, |
| dispatch_continuation_t dc) |
| { |
| dispatch_group_enter(dg); |
| dc->dc_data = dg; |
| _dispatch_continuation_async(dq, dc); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_group_async_f(dispatch_group_t dg, dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT | DISPATCH_OBJ_GROUP_BIT; |
| |
| _dispatch_continuation_init_f(dc, dq, ctxt, func, 0, 0, dc_flags); |
| _dispatch_continuation_group_async(dg, dq, dc); |
| } |
| |
| #ifdef __BLOCKS__ |
| void |
| dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, |
| dispatch_block_t db) |
| { |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| uintptr_t dc_flags = DISPATCH_OBJ_CONSUME_BIT | DISPATCH_OBJ_GROUP_BIT; |
| |
| _dispatch_continuation_init(dc, dq, db, 0, 0, dc_flags); |
| _dispatch_continuation_group_async(dg, dq, dc); |
| } |
| #endif |
| |
| #pragma mark - |
| #pragma mark _dispatch_sync_invoke / _dispatch_sync_complete |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_non_barrier_complete(dispatch_queue_t dq) |
| { |
| uint64_t old_state, new_state, owner_self = _dispatch_lock_value_for_self(); |
| |
| // see _dispatch_queue_resume() |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| new_state = old_state - DISPATCH_QUEUE_WIDTH_INTERVAL; |
| if (unlikely(_dq_state_drain_locked(old_state))) { |
| // make drain_try_unlock() fail and reconsider whether there's |
| // enough width now for a new item |
| new_state |= DISPATCH_QUEUE_DIRTY; |
| } else if (likely(_dq_state_is_runnable(new_state))) { |
| uint64_t full_width = new_state; |
| if (_dq_state_has_pending_barrier(old_state)) { |
| full_width -= DISPATCH_QUEUE_PENDING_BARRIER; |
| full_width += DISPATCH_QUEUE_WIDTH_INTERVAL; |
| full_width += DISPATCH_QUEUE_IN_BARRIER; |
| } else { |
| full_width += dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| full_width += DISPATCH_QUEUE_IN_BARRIER; |
| } |
| if ((full_width & DISPATCH_QUEUE_WIDTH_MASK) == |
| DISPATCH_QUEUE_WIDTH_FULL_BIT) { |
| new_state = full_width; |
| new_state &= ~DISPATCH_QUEUE_DIRTY; |
| new_state |= owner_self; |
| } else if (_dq_state_is_dirty(old_state)) { |
| new_state |= DISPATCH_QUEUE_ENQUEUED; |
| } |
| } |
| }); |
| |
| if ((old_state ^ new_state) & DISPATCH_QUEUE_IN_BARRIER) { |
| if (_dq_state_is_dirty(old_state)) { |
| // <rdar://problem/14637483> |
| // dependency ordering for dq state changes that were flushed |
| // and not acted upon |
| os_atomic_thread_fence(dependency); |
| dq = os_atomic_force_dependency_on(dq, old_state); |
| } |
| return _dispatch_queue_barrier_complete(dq, 0, 0); |
| } |
| |
| if ((old_state ^ new_state) & DISPATCH_QUEUE_ENQUEUED) { |
| _dispatch_retain_2(dq); |
| dispatch_assert(!_dq_state_is_base_wlh(new_state)); |
| return dx_push(dq->do_targetq, dq, _dq_state_max_qos(new_state)); |
| } |
| } |
| |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_sync_function_invoke_inline(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| dispatch_thread_frame_s dtf; |
| _dispatch_thread_frame_push(&dtf, dq); |
| _dispatch_client_callout(ctxt, func); |
| _dispatch_perfmon_workitem_inc(); |
| _dispatch_thread_frame_pop(&dtf); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_function_invoke(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| _dispatch_sync_function_invoke_inline(dq, ctxt, func); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_complete_recurse(dispatch_queue_t dq, dispatch_queue_t stop_dq, |
| uintptr_t dc_flags) |
| { |
| bool barrier = (dc_flags & DISPATCH_OBJ_BARRIER_BIT); |
| do { |
| if (dq == stop_dq) return; |
| if (barrier) { |
| _dispatch_queue_barrier_complete(dq, 0, 0); |
| } else { |
| _dispatch_queue_non_barrier_complete(dq); |
| } |
| dq = dq->do_targetq; |
| barrier = (dq->dq_width == 1); |
| } while (unlikely(dq->do_targetq)); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_invoke_and_complete_recurse(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func, uintptr_t dc_flags) |
| { |
| _dispatch_sync_function_invoke_inline(dq, ctxt, func); |
| _dispatch_sync_complete_recurse(dq, NULL, dc_flags); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_invoke_and_complete(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| _dispatch_sync_function_invoke_inline(dq, ctxt, func); |
| _dispatch_queue_non_barrier_complete(dq); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_barrier_sync_invoke_and_complete(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| _dispatch_sync_function_invoke_inline(dq, ctxt, func); |
| dx_wakeup(dq, 0, DISPATCH_WAKEUP_BARRIER_COMPLETE); |
| } |
| |
| /* |
| * This is an optimized version of _dispatch_barrier_sync_invoke_and_complete |
| * |
| * For queues we can cheat and inline the unlock code, which is invalid |
| * for objects with a more complex state machine (sources or mach channels) |
| */ |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_barrier_sync_invoke_and_complete(dispatch_queue_t dq, |
| void *ctxt, dispatch_function_t func) |
| { |
| _dispatch_sync_function_invoke_inline(dq, ctxt, func); |
| if (unlikely(dq->dq_items_tail || dq->dq_width > 1)) { |
| return _dispatch_queue_barrier_complete(dq, 0, 0); |
| } |
| |
| // Presence of any of these bits requires more work that only |
| // _dispatch_queue_barrier_complete() handles properly |
| // |
| // Note: testing for RECEIVED_OVERRIDE or RECEIVED_SYNC_WAIT without |
| // checking the role is sloppy, but is a super fast check, and neither of |
| // these bits should be set if the lock was never contended/discovered. |
| const uint64_t fail_unlock_mask = DISPATCH_QUEUE_SUSPEND_BITS_MASK | |
| DISPATCH_QUEUE_ENQUEUED | DISPATCH_QUEUE_DIRTY | |
| DISPATCH_QUEUE_RECEIVED_OVERRIDE | DISPATCH_QUEUE_SYNC_TRANSFER | |
| DISPATCH_QUEUE_RECEIVED_SYNC_WAIT; |
| uint64_t old_state, new_state; |
| |
| // similar to _dispatch_queue_drain_try_unlock |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, release, { |
| new_state = old_state - DISPATCH_QUEUE_SERIAL_DRAIN_OWNED; |
| new_state &= ~DISPATCH_QUEUE_DRAIN_UNLOCK_MASK; |
| new_state &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| if (unlikely(old_state & fail_unlock_mask)) { |
| os_atomic_rmw_loop_give_up({ |
| return _dispatch_queue_barrier_complete(dq, 0, 0); |
| }); |
| } |
| }); |
| if (_dq_state_is_base_wlh(old_state)) { |
| _dispatch_event_loop_assert_not_owned((dispatch_wlh_t)dq); |
| } |
| } |
| |
| #pragma mark - |
| #pragma mark _dispatch_sync_wait / _dispatch_sync_waiter_wake |
| |
| #define DISPATCH_SYNC_WAITER_NO_UNLOCK (~0ull) |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_waiter_wake(dispatch_sync_context_t dsc, |
| dispatch_wlh_t wlh, uint64_t old_state, uint64_t new_state) |
| { |
| dispatch_wlh_t waiter_wlh = dsc->dc_data; |
| |
| if (_dq_state_in_sync_transfer(old_state) || |
| _dq_state_in_sync_transfer(new_state) || |
| (waiter_wlh != DISPATCH_WLH_ANON)) { |
| _dispatch_event_loop_wake_owner(dsc, wlh, old_state, new_state); |
| } |
| if (waiter_wlh == DISPATCH_WLH_ANON) { |
| if (dsc->dsc_override_qos > dsc->dsc_override_qos_floor) { |
| _dispatch_wqthread_override_start(dsc->dsc_waiter, |
| dsc->dsc_override_qos); |
| } |
| _dispatch_thread_event_signal(&dsc->dsc_event); |
| } |
| _dispatch_introspection_queue_item_complete(dsc->_as_dc); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_waiter_redirect_or_wake(dispatch_queue_t dq, uint64_t owned, |
| dispatch_object_t dou) |
| { |
| dispatch_sync_context_t dsc = (dispatch_sync_context_t)dou._dc; |
| uint64_t next_owner = 0, old_state, new_state; |
| dispatch_wlh_t wlh = NULL; |
| |
| _dispatch_trace_continuation_pop(dq, dsc->_as_dc); |
| |
| if (owned == DISPATCH_SYNC_WAITER_NO_UNLOCK) { |
| dispatch_assert(!(dsc->dc_flags & DISPATCH_OBJ_BARRIER_BIT)); |
| new_state = old_state = os_atomic_load2o(dq, dq_state, relaxed); |
| } else { |
| if (dsc->dc_flags & DISPATCH_OBJ_BARRIER_BIT) { |
| next_owner = _dispatch_lock_value_from_tid(dsc->dsc_waiter); |
| } |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, release, { |
| new_state = old_state - owned; |
| new_state &= ~DISPATCH_QUEUE_DRAIN_UNLOCK_MASK; |
| new_state &= ~DISPATCH_QUEUE_DIRTY; |
| new_state |= next_owner; |
| if (_dq_state_is_base_wlh(old_state)) { |
| new_state |= DISPATCH_QUEUE_SYNC_TRANSFER; |
| } |
| }); |
| if (_dq_state_is_base_wlh(old_state)) { |
| wlh = (dispatch_wlh_t)dq; |
| } else if (_dq_state_received_override(old_state)) { |
| // Ensure that the root queue sees that this thread was overridden. |
| _dispatch_set_basepri_override_qos(_dq_state_max_qos(old_state)); |
| } |
| } |
| |
| if (dsc->dc_data == DISPATCH_WLH_ANON) { |
| if (dsc->dsc_override_qos < _dq_state_max_qos(old_state)) { |
| dsc->dsc_override_qos = _dq_state_max_qos(old_state); |
| } |
| } |
| |
| if (unlikely(_dq_state_is_inner_queue(old_state))) { |
| dispatch_queue_t tq = dq->do_targetq; |
| if (likely(tq->dq_width == 1)) { |
| dsc->dc_flags = DISPATCH_OBJ_BARRIER_BIT | |
| DISPATCH_OBJ_SYNC_WAITER_BIT; |
| } else { |
| dsc->dc_flags = DISPATCH_OBJ_SYNC_WAITER_BIT; |
| } |
| _dispatch_introspection_queue_item_complete(dsc->_as_dc); |
| return _dispatch_queue_push_sync_waiter(tq, dsc, 0); |
| } |
| |
| return _dispatch_sync_waiter_wake(dsc, wlh, old_state, new_state); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_class_barrier_complete(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags, dispatch_queue_wakeup_target_t target, |
| uint64_t owned) |
| { |
| uint64_t old_state, new_state, enqueue; |
| dispatch_queue_t tq; |
| |
| if (target == DISPATCH_QUEUE_WAKEUP_MGR) { |
| tq = &_dispatch_mgr_q; |
| enqueue = DISPATCH_QUEUE_ENQUEUED_ON_MGR; |
| } else if (target) { |
| tq = (target == DISPATCH_QUEUE_WAKEUP_TARGET) ? dq->do_targetq : target; |
| enqueue = DISPATCH_QUEUE_ENQUEUED; |
| } else { |
| tq = NULL; |
| enqueue = 0; |
| } |
| |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, release, { |
| new_state = _dq_state_merge_qos(old_state - owned, qos); |
| new_state &= ~DISPATCH_QUEUE_DRAIN_UNLOCK_MASK; |
| if (unlikely(_dq_state_is_suspended(old_state))) { |
| new_state |= DLOCK_OWNER_MASK; |
| } else if (enqueue) { |
| new_state |= enqueue; |
| } else if (unlikely(_dq_state_is_dirty(old_state))) { |
| os_atomic_rmw_loop_give_up({ |
| // just renew the drain lock with an acquire barrier, to see |
| // what the enqueuer that set DIRTY has done. |
| // the xor generates better assembly as DISPATCH_QUEUE_DIRTY |
| // is already in a register |
| os_atomic_xor2o(dq, dq_state, DISPATCH_QUEUE_DIRTY, acquire); |
| flags |= DISPATCH_WAKEUP_BARRIER_COMPLETE; |
| return dx_wakeup(dq, qos, flags); |
| }); |
| } else if (_dq_state_is_base_wlh(old_state)) { |
| new_state &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| new_state &= ~DISPATCH_QUEUE_ENQUEUED; |
| } else { |
| new_state &= ~DISPATCH_QUEUE_MAX_QOS_MASK; |
| } |
| }); |
| old_state -= owned; |
| dispatch_assert(_dq_state_drain_locked_by_self(old_state)); |
| dispatch_assert(!_dq_state_is_enqueued_on_manager(old_state)); |
| |
| |
| if (_dq_state_received_override(old_state)) { |
| // Ensure that the root queue sees that this thread was overridden. |
| _dispatch_set_basepri_override_qos(_dq_state_max_qos(old_state)); |
| } |
| |
| if (tq) { |
| if (likely((old_state ^ new_state) & enqueue)) { |
| dispatch_assert(_dq_state_is_enqueued(new_state)); |
| dispatch_assert(flags & DISPATCH_WAKEUP_CONSUME_2); |
| return _dispatch_queue_push_queue(tq, dq, new_state); |
| } |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| // <rdar://problem/27694093> when doing sync to async handoff |
| // if the queue received an override we have to forecefully redrive |
| // the same override so that a new stealer is enqueued because |
| // the previous one may be gone already |
| if (_dq_state_should_override(new_state)) { |
| return _dispatch_queue_class_wakeup_with_override(dq, new_state, |
| flags); |
| } |
| #endif |
| } |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_barrier_complete(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags) |
| { |
| dispatch_continuation_t dc_tmp, dc_start = NULL, dc_end = NULL; |
| dispatch_queue_wakeup_target_t target = DISPATCH_QUEUE_WAKEUP_NONE; |
| struct dispatch_object_s *dc = NULL; |
| uint64_t owned = DISPATCH_QUEUE_IN_BARRIER + |
| dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| size_t count = 0; |
| |
| dispatch_assert(dx_metatype(dq) == _DISPATCH_QUEUE_TYPE); |
| |
| if (dq->dq_items_tail && !DISPATCH_QUEUE_IS_SUSPENDED(dq)) { |
| dc = _dispatch_queue_head(dq); |
| if (!_dispatch_object_is_sync_waiter(dc)) { |
| // not a slow item, needs to wake up |
| } else if (likely(dq->dq_width == 1) || |
| _dispatch_object_is_barrier(dc)) { |
| // rdar://problem/8290662 "barrier/writer lock transfer" |
| dc_start = dc_end = (dispatch_continuation_t)dc; |
| owned = 0; |
| count = 1; |
| dc = _dispatch_queue_next(dq, dc); |
| } else { |
| // <rdar://problem/10164594> "reader lock transfer" |
| // we must not wake waiters immediately because our right |
| // for dequeuing is granted through holding the full "barrier" width |
| // which a signaled work item could relinquish out from our feet |
| dc_start = (dispatch_continuation_t)dc; |
| do { |
| // no check on width here because concurrent queues |
| // do not respect width for blocked readers, the thread |
| // is already spent anyway |
| dc_end = (dispatch_continuation_t)dc; |
| owned -= DISPATCH_QUEUE_WIDTH_INTERVAL; |
| count++; |
| dc = _dispatch_queue_next(dq, dc); |
| } while (dc && _dispatch_object_is_sync_waiter_non_barrier(dc)); |
| } |
| |
| if (count) { |
| do { |
| dc_tmp = dc_start; |
| dc_start = dc_start->do_next; |
| _dispatch_sync_waiter_redirect_or_wake(dq, owned, dc_tmp); |
| owned = DISPATCH_SYNC_WAITER_NO_UNLOCK; |
| } while (dc_tmp != dc_end); |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| return; |
| } |
| if (!(flags & DISPATCH_WAKEUP_CONSUME_2)) { |
| _dispatch_retain_2(dq); |
| flags |= DISPATCH_WAKEUP_CONSUME_2; |
| } |
| target = DISPATCH_QUEUE_WAKEUP_TARGET; |
| } |
| |
| return _dispatch_queue_class_barrier_complete(dq, qos, flags, target,owned); |
| } |
| |
| #if DISPATCH_COCOA_COMPAT |
| static void |
| _dispatch_sync_thread_bound_invoke(void *ctxt) |
| { |
| dispatch_sync_context_t dsc = ctxt; |
| dispatch_queue_t cq = _dispatch_queue_get_current(); |
| dispatch_queue_t orig_dq = dsc->dc_other; |
| dispatch_thread_frame_s dtf; |
| dispatch_assert(_dispatch_queue_is_thread_bound(cq)); |
| |
| // the block runs on the thread the queue is bound to and not |
| // on the calling thread, but we mean to see the calling thread |
| // dispatch thread frames, so we fake the link, and then undo it |
| _dispatch_thread_frame_push_and_rebase(&dtf, orig_dq, &dsc->dsc_dtf); |
| _dispatch_client_callout(dsc->dsc_ctxt, dsc->dsc_func); |
| _dispatch_thread_frame_pop(&dtf); |
| |
| // communicate back to _dispatch_sync_wait who the thread bound queue |
| // was so that we skip it during _dispatch_sync_complete_recurse |
| dsc->dc_other = cq; |
| dsc->dsc_func = NULL; |
| _dispatch_thread_event_signal(&dsc->dsc_event); // release |
| } |
| #endif |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline uint64_t |
| _dispatch_sync_wait_prepare(dispatch_queue_t dq) |
| { |
| uint64_t old_state, new_state; |
| |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| if (_dq_state_is_suspended(old_state) || |
| !_dq_state_is_base_wlh(old_state)) { |
| os_atomic_rmw_loop_give_up(return old_state); |
| } |
| if (!_dq_state_drain_locked(old_state) || |
| _dq_state_in_sync_transfer(old_state)) { |
| os_atomic_rmw_loop_give_up(return old_state); |
| } |
| new_state = old_state | DISPATCH_QUEUE_RECEIVED_SYNC_WAIT; |
| }); |
| return new_state; |
| } |
| |
| static void |
| _dispatch_sync_waiter_compute_wlh(dispatch_queue_t dq, |
| dispatch_sync_context_t dsc) |
| { |
| bool needs_locking = _dispatch_queue_is_legacy(dq); |
| |
| if (needs_locking) { |
| dsc->dsc_release_storage = true; |
| _dispatch_queue_sidelock_lock(dq); |
| } |
| |
| dispatch_queue_t tq = dq->do_targetq; |
| uint64_t dq_state = _dispatch_sync_wait_prepare(tq); |
| |
| if (_dq_state_is_suspended(dq_state) || |
| _dq_state_is_base_anon(dq_state)) { |
| dsc->dsc_release_storage = false; |
| dsc->dc_data = DISPATCH_WLH_ANON; |
| } else if (_dq_state_is_base_wlh(dq_state)) { |
| if (dsc->dsc_release_storage) { |
| _dispatch_queue_retain_storage(tq); |
| } |
| dsc->dc_data = (dispatch_wlh_t)tq; |
| } else { |
| _dispatch_sync_waiter_compute_wlh(tq, dsc); |
| } |
| if (needs_locking) _dispatch_queue_sidelock_unlock(dq); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_wait(dispatch_queue_t top_dq, void *ctxt, |
| dispatch_function_t func, uintptr_t top_dc_flags, |
| dispatch_queue_t dq, uintptr_t dc_flags) |
| { |
| pthread_priority_t pp = _dispatch_get_priority(); |
| dispatch_tid tid = _dispatch_tid_self(); |
| dispatch_qos_t qos; |
| uint64_t dq_state; |
| |
| dq_state = _dispatch_sync_wait_prepare(dq); |
| if (unlikely(_dq_state_drain_locked_by(dq_state, tid))) { |
| DISPATCH_CLIENT_CRASH((uintptr_t)dq_state, |
| "dispatch_sync called on queue " |
| "already owned by current thread"); |
| } |
| |
| struct dispatch_sync_context_s dsc = { |
| .dc_flags = dc_flags | DISPATCH_OBJ_SYNC_WAITER_BIT, |
| .dc_other = top_dq, |
| .dc_priority = pp | _PTHREAD_PRIORITY_ENFORCE_FLAG, |
| .dc_voucher = DISPATCH_NO_VOUCHER, |
| .dsc_func = func, |
| .dsc_ctxt = ctxt, |
| .dsc_waiter = tid, |
| }; |
| if (_dq_state_is_suspended(dq_state) || |
| _dq_state_is_base_anon(dq_state)) { |
| dsc.dc_data = DISPATCH_WLH_ANON; |
| } else if (_dq_state_is_base_wlh(dq_state)) { |
| dsc.dc_data = (dispatch_wlh_t)dq; |
| } else { |
| _dispatch_sync_waiter_compute_wlh(dq, &dsc); |
| } |
| #if DISPATCH_COCOA_COMPAT |
| // It's preferred to execute synchronous blocks on the current thread |
| // due to thread-local side effects, etc. However, blocks submitted |
| // to the main thread MUST be run on the main thread |
| // |
| // Since we don't know whether that will happen, save the frame linkage |
| // for the sake of _dispatch_sync_thread_bound_invoke |
| _dispatch_thread_frame_save_state(&dsc.dsc_dtf); |
| |
| // Since the continuation doesn't have the CONSUME bit, the voucher will be |
| // retained on adoption on the thread bound queue if it happens so we can |
| // borrow this thread's reference |
| dsc.dc_voucher = _voucher_get(); |
| dsc.dc_func = _dispatch_sync_thread_bound_invoke; |
| dsc.dc_ctxt = &dsc; |
| #endif |
| |
| if (dsc.dc_data == DISPATCH_WLH_ANON) { |
| dsc.dsc_override_qos_floor = dsc.dsc_override_qos = |
| _dispatch_get_basepri_override_qos_floor(); |
| qos = _dispatch_qos_from_pp(pp); |
| _dispatch_thread_event_init(&dsc.dsc_event); |
| } else { |
| qos = 0; |
| } |
| _dispatch_queue_push_sync_waiter(dq, &dsc, qos); |
| if (dsc.dc_data == DISPATCH_WLH_ANON) { |
| _dispatch_thread_event_wait(&dsc.dsc_event); // acquire |
| _dispatch_thread_event_destroy(&dsc.dsc_event); |
| // If _dispatch_sync_waiter_wake() gave this thread an override, |
| // ensure that the root queue sees it. |
| if (dsc.dsc_override_qos > dsc.dsc_override_qos_floor) { |
| _dispatch_set_basepri_override_qos(dsc.dsc_override_qos); |
| } |
| } else { |
| _dispatch_event_loop_wait_for_ownership(&dsc); |
| } |
| _dispatch_introspection_sync_begin(top_dq); |
| #if DISPATCH_COCOA_COMPAT |
| if (unlikely(dsc.dsc_func == NULL)) { |
| // Queue bound to a non-dispatch thread, the continuation already ran |
| // so just unlock all the things, except for the thread bound queue |
| dispatch_queue_t bound_dq = dsc.dc_other; |
| return _dispatch_sync_complete_recurse(top_dq, bound_dq, top_dc_flags); |
| } |
| #endif |
| _dispatch_sync_invoke_and_complete_recurse(top_dq, ctxt, func,top_dc_flags); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_f_slow(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func, uintptr_t dc_flags) |
| { |
| if (unlikely(!dq->do_targetq)) { |
| return _dispatch_sync_function_invoke(dq, ctxt, func); |
| } |
| _dispatch_sync_wait(dq, ctxt, func, dc_flags, dq, dc_flags); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_sync / dispatch_barrier_sync |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_recurse(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func, uintptr_t dc_flags) |
| { |
| dispatch_tid tid = _dispatch_tid_self(); |
| dispatch_queue_t tq = dq->do_targetq; |
| |
| do { |
| if (likely(tq->dq_width == 1)) { |
| if (unlikely(!_dispatch_queue_try_acquire_barrier_sync(tq, tid))) { |
| return _dispatch_sync_wait(dq, ctxt, func, dc_flags, tq, |
| DISPATCH_OBJ_BARRIER_BIT); |
| } |
| } else { |
| if (unlikely(!_dispatch_queue_try_reserve_sync_width(tq))) { |
| return _dispatch_sync_wait(dq, ctxt, func, dc_flags, tq, 0); |
| } |
| } |
| tq = tq->do_targetq; |
| } while (unlikely(tq->do_targetq)); |
| |
| return _dispatch_sync_invoke_and_complete_recurse(dq, ctxt, func, dc_flags); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_barrier_sync_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| dispatch_tid tid = _dispatch_tid_self(); |
| |
| // The more correct thing to do would be to merge the qos of the thread |
| // that just acquired the barrier lock into the queue state. |
| // |
| // However this is too expensive for the fastpath, so skip doing it. |
| // The chosen tradeoff is that if an enqueue on a lower priority thread |
| // contends with this fastpath, this thread may receive a useless override. |
| // |
| // Global concurrent queues and queues bound to non-dispatch threads |
| // always fall into the slow case, see DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE |
| if (unlikely(!_dispatch_queue_try_acquire_barrier_sync(dq, tid))) { |
| return _dispatch_sync_f_slow(dq, ctxt, func, DISPATCH_OBJ_BARRIER_BIT); |
| } |
| |
| _dispatch_introspection_sync_begin(dq); |
| if (unlikely(dq->do_targetq->do_targetq)) { |
| return _dispatch_sync_recurse(dq, ctxt, func, DISPATCH_OBJ_BARRIER_BIT); |
| } |
| _dispatch_queue_barrier_sync_invoke_and_complete(dq, ctxt, func); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| dispatch_sync_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t func) |
| { |
| if (likely(dq->dq_width == 1)) { |
| return dispatch_barrier_sync_f(dq, ctxt, func); |
| } |
| |
| // Global concurrent queues and queues bound to non-dispatch threads |
| // always fall into the slow case, see DISPATCH_ROOT_QUEUE_STATE_INIT_VALUE |
| if (unlikely(!_dispatch_queue_try_reserve_sync_width(dq))) { |
| return _dispatch_sync_f_slow(dq, ctxt, func, 0); |
| } |
| |
| _dispatch_introspection_sync_begin(dq); |
| if (unlikely(dq->do_targetq->do_targetq)) { |
| return _dispatch_sync_recurse(dq, ctxt, func, 0); |
| } |
| _dispatch_sync_invoke_and_complete(dq, ctxt, func); |
| } |
| |
| #ifdef __BLOCKS__ |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_sync_block_with_private_data(dispatch_queue_t dq, |
| dispatch_block_t work, dispatch_block_flags_t flags) |
| { |
| dispatch_block_private_data_t dbpd = _dispatch_block_get_data(work); |
| pthread_priority_t op = 0, p = 0; |
| |
| flags |= dbpd->dbpd_flags; |
| op = _dispatch_block_invoke_should_set_priority(flags, dbpd->dbpd_priority); |
| if (op) { |
| p = dbpd->dbpd_priority; |
| } |
| voucher_t ov, v = DISPATCH_NO_VOUCHER; |
| if (flags & DISPATCH_BLOCK_HAS_VOUCHER) { |
| v = dbpd->dbpd_voucher; |
| } |
| ov = _dispatch_set_priority_and_voucher(p, v, 0); |
| |
| // balanced in d_block_sync_invoke or d_block_wait |
| if (os_atomic_cmpxchg2o(dbpd, dbpd_queue, NULL, dq->_as_oq, relaxed)) { |
| _dispatch_retain_2(dq); |
| } |
| if (flags & DISPATCH_BLOCK_BARRIER) { |
| dispatch_barrier_sync_f(dq, work, _dispatch_block_sync_invoke); |
| } else { |
| dispatch_sync_f(dq, work, _dispatch_block_sync_invoke); |
| } |
| _dispatch_reset_priority_and_voucher(op, ov); |
| } |
| |
| void |
| dispatch_barrier_sync(dispatch_queue_t dq, dispatch_block_t work) |
| { |
| if (unlikely(_dispatch_block_has_private_data(work))) { |
| dispatch_block_flags_t flags = DISPATCH_BLOCK_BARRIER; |
| return _dispatch_sync_block_with_private_data(dq, work, flags); |
| } |
| dispatch_barrier_sync_f(dq, work, _dispatch_Block_invoke(work)); |
| } |
| |
| void |
| dispatch_sync(dispatch_queue_t dq, dispatch_block_t work) |
| { |
| if (unlikely(_dispatch_block_has_private_data(work))) { |
| return _dispatch_sync_block_with_private_data(dq, work, 0); |
| } |
| dispatch_sync_f(dq, work, _dispatch_Block_invoke(work)); |
| } |
| #endif // __BLOCKS__ |
| |
| #pragma mark - |
| #pragma mark dispatch_trysync |
| |
| // Use for mutation of queue-/source-internal state only |
| // ignores target queue hierarchy! |
| DISPATCH_NOINLINE |
| void |
| _dispatch_barrier_trysync_or_async_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t func) |
| { |
| dispatch_tid tid = _dispatch_tid_self(); |
| if (unlikely(!_dispatch_queue_try_acquire_barrier_sync(dq, tid))) { |
| return _dispatch_barrier_async_detached_f(dq, ctxt, func); |
| } |
| _dispatch_barrier_sync_invoke_and_complete(dq, ctxt, func); |
| } |
| |
| DISPATCH_NOINLINE |
| static long |
| _dispatch_trysync_recurse(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t f, uintptr_t dc_flags) |
| { |
| dispatch_tid tid = _dispatch_tid_self(); |
| dispatch_queue_t q, tq = dq->do_targetq; |
| |
| for (;;) { |
| if (likely(tq->do_targetq == NULL)) { |
| _dispatch_sync_invoke_and_complete_recurse(dq, ctxt, f, dc_flags); |
| return true; |
| } |
| if (unlikely(_dispatch_queue_cannot_trysync(tq))) { |
| for (q = dq; q != tq; q = q->do_targetq) { |
| _dispatch_queue_atomic_flags_set(q, DQF_CANNOT_TRYSYNC); |
| } |
| break; |
| } |
| if (likely(tq->dq_width == 1)) { |
| if (unlikely(!_dispatch_queue_try_acquire_barrier_sync(tq, tid))) { |
| break; |
| } |
| } else { |
| if (unlikely(!_dispatch_queue_try_reserve_sync_width(tq))) { |
| break; |
| } |
| } |
| tq = tq->do_targetq; |
| } |
| |
| _dispatch_sync_complete_recurse(dq, tq, dc_flags); |
| return false; |
| } |
| |
| DISPATCH_NOINLINE |
| long |
| _dispatch_barrier_trysync_f(dispatch_queue_t dq, void *ctxt, |
| dispatch_function_t f) |
| { |
| dispatch_tid tid = _dispatch_tid_self(); |
| if (unlikely(!dq->do_targetq)) { |
| DISPATCH_CLIENT_CRASH(dq, "_dispatch_trsync called on a root queue"); |
| } |
| if (unlikely(_dispatch_queue_cannot_trysync(dq))) { |
| return false; |
| } |
| if (unlikely(!_dispatch_queue_try_acquire_barrier_sync(dq, tid))) { |
| return false; |
| } |
| return _dispatch_trysync_recurse(dq, ctxt, f, DISPATCH_OBJ_BARRIER_BIT); |
| } |
| |
| DISPATCH_NOINLINE |
| long |
| _dispatch_trysync_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t f) |
| { |
| if (likely(dq->dq_width == 1)) { |
| return _dispatch_barrier_trysync_f(dq, ctxt, f); |
| } |
| if (unlikely(!dq->do_targetq)) { |
| DISPATCH_CLIENT_CRASH(dq, "_dispatch_trsync called on a root queue"); |
| } |
| if (unlikely(_dispatch_queue_cannot_trysync(dq))) { |
| return false; |
| } |
| if (unlikely(!_dispatch_queue_try_reserve_sync_width(dq))) { |
| return false; |
| } |
| return _dispatch_trysync_recurse(dq, ctxt, f, 0); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_wakeup |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_queue_wakeup(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags) |
| { |
| dispatch_queue_wakeup_target_t target = DISPATCH_QUEUE_WAKEUP_NONE; |
| |
| if (unlikely(flags & DISPATCH_WAKEUP_BARRIER_COMPLETE)) { |
| return _dispatch_queue_barrier_complete(dq, qos, flags); |
| } |
| if (_dispatch_queue_class_probe(dq)) { |
| target = DISPATCH_QUEUE_WAKEUP_TARGET; |
| } |
| return _dispatch_queue_class_wakeup(dq, qos, flags, target); |
| } |
| |
| #if DISPATCH_COCOA_COMPAT |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_runloop_handle_is_valid(dispatch_runloop_handle_t handle) |
| { |
| #if TARGET_OS_MAC |
| return MACH_PORT_VALID(handle); |
| #elif defined(__linux__) |
| return handle >= 0; |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_runloop_handle_t |
| _dispatch_runloop_queue_get_handle(dispatch_queue_t dq) |
| { |
| #if TARGET_OS_MAC |
| return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt); |
| #elif defined(__linux__) |
| // decode: 0 is a valid fd, so offset by 1 to distinguish from NULL |
| return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt) - 1; |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_runloop_queue_set_handle(dispatch_queue_t dq, dispatch_runloop_handle_t handle) |
| { |
| #if TARGET_OS_MAC |
| dq->do_ctxt = (void *)(uintptr_t)handle; |
| #elif defined(__linux__) |
| // encode: 0 is a valid fd, so offset by 1 to distinguish from NULL |
| dq->do_ctxt = (void *)(uintptr_t)(handle + 1); |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_qos_t |
| _dispatch_runloop_queue_reset_max_qos(dispatch_queue_class_t dqu) |
| { |
| uint64_t old_state, clear_bits = DISPATCH_QUEUE_MAX_QOS_MASK | |
| DISPATCH_QUEUE_RECEIVED_OVERRIDE; |
| old_state = os_atomic_and_orig2o(dqu._dq, dq_state, ~clear_bits, relaxed); |
| return _dq_state_max_qos(old_state); |
| } |
| #endif // DISPATCH_COCOA_COMPAT |
| |
| void |
| _dispatch_runloop_queue_wakeup(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags) |
| { |
| #if DISPATCH_COCOA_COMPAT |
| if (slowpath(_dispatch_queue_atomic_flags(dq) & DQF_RELEASED)) { |
| // <rdar://problem/14026816> |
| return _dispatch_queue_wakeup(dq, qos, flags); |
| } |
| |
| if (flags & DISPATCH_WAKEUP_MAKE_DIRTY) { |
| os_atomic_or2o(dq, dq_state, DISPATCH_QUEUE_DIRTY, release); |
| } |
| if (_dispatch_queue_class_probe(dq)) { |
| return _dispatch_runloop_queue_poke(dq, qos, flags); |
| } |
| |
| qos = _dispatch_runloop_queue_reset_max_qos(dq); |
| if (qos) { |
| mach_port_t owner = DISPATCH_QUEUE_DRAIN_OWNER(dq); |
| if (_dispatch_queue_class_probe(dq)) { |
| _dispatch_runloop_queue_poke(dq, qos, flags); |
| } |
| _dispatch_thread_override_end(owner, dq); |
| return; |
| } |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| #else |
| return _dispatch_queue_wakeup(dq, qos, flags); |
| #endif |
| } |
| |
| void |
| _dispatch_main_queue_wakeup(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags) |
| { |
| #if DISPATCH_COCOA_COMPAT |
| if (_dispatch_queue_is_thread_bound(dq)) { |
| return _dispatch_runloop_queue_wakeup(dq, qos, flags); |
| } |
| #endif |
| return _dispatch_queue_wakeup(dq, qos, flags); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch root queues poke |
| |
| #if DISPATCH_COCOA_COMPAT |
| static inline void |
| _dispatch_runloop_queue_class_poke(dispatch_queue_t dq) |
| { |
| dispatch_runloop_handle_t handle = _dispatch_runloop_queue_get_handle(dq); |
| if (!_dispatch_runloop_handle_is_valid(handle)) { |
| return; |
| } |
| |
| #if HAVE_MACH |
| mach_port_t mp = handle; |
| kern_return_t kr = _dispatch_send_wakeup_runloop_thread(mp, 0); |
| switch (kr) { |
| case MACH_SEND_TIMEOUT: |
| case MACH_SEND_TIMED_OUT: |
| case MACH_SEND_INVALID_DEST: |
| break; |
| default: |
| (void)dispatch_assume_zero(kr); |
| break; |
| } |
| #elif defined(__linux__) |
| int result; |
| do { |
| result = eventfd_write(handle, 1); |
| } while (result == -1 && errno == EINTR); |
| (void)dispatch_assume_zero(result); |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_runloop_queue_poke(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags) |
| { |
| // it's not useful to handle WAKEUP_MAKE_DIRTY because mach_msg() will have |
| // a release barrier and that when runloop queues stop being thread-bound |
| // they have a non optional wake-up to start being a "normal" queue |
| // either in _dispatch_runloop_queue_xref_dispose, |
| // or in _dispatch_queue_cleanup2() for the main thread. |
| uint64_t old_state, new_state; |
| |
| if (dq == &_dispatch_main_q) { |
| dispatch_once_f(&_dispatch_main_q_handle_pred, dq, |
| _dispatch_runloop_queue_handle_init); |
| } |
| |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| new_state = _dq_state_merge_qos(old_state, qos); |
| if (old_state == new_state) { |
| os_atomic_rmw_loop_give_up(goto no_change); |
| } |
| }); |
| |
| dispatch_qos_t dq_qos = _dispatch_priority_qos(dq->dq_priority); |
| if (qos > dq_qos) { |
| mach_port_t owner = _dq_state_drain_owner(new_state); |
| pthread_priority_t pp = _dispatch_qos_to_pp(qos); |
| _dispatch_thread_override_start(owner, pp, dq); |
| if (_dq_state_max_qos(old_state) > dq_qos) { |
| _dispatch_thread_override_end(owner, dq); |
| } |
| } |
| no_change: |
| _dispatch_runloop_queue_class_poke(dq); |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| } |
| #endif |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_global_queue_poke_slow(dispatch_queue_t dq, int n, int floor) |
| { |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| int remaining = n; |
| int r = ENOSYS; |
| |
| _dispatch_root_queues_init(); |
| _dispatch_debug_root_queue(dq, __func__); |
| #if DISPATCH_USE_WORKQUEUES |
| #if DISPATCH_USE_PTHREAD_POOL |
| if (qc->dgq_kworkqueue != (void*)(~0ul)) |
| #endif |
| { |
| _dispatch_root_queue_debug("requesting new worker thread for global " |
| "queue: %p", dq); |
| #if DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| if (qc->dgq_kworkqueue) { |
| pthread_workitem_handle_t wh; |
| unsigned int gen_cnt; |
| do { |
| r = pthread_workqueue_additem_np(qc->dgq_kworkqueue, |
| _dispatch_worker_thread4, dq, &wh, &gen_cnt); |
| (void)dispatch_assume_zero(r); |
| } while (--remaining); |
| return; |
| } |
| #endif // DISPATCH_USE_LEGACY_WORKQUEUE_FALLBACK |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| r = _pthread_workqueue_addthreads(remaining, |
| _dispatch_priority_to_pp(dq->dq_priority)); |
| #elif DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| r = pthread_workqueue_addthreads_np(qc->dgq_wq_priority, |
| qc->dgq_wq_options, remaining); |
| #endif |
| (void)dispatch_assume_zero(r); |
| return; |
| } |
| #endif // DISPATCH_USE_WORKQUEUES |
| #if DISPATCH_USE_PTHREAD_POOL |
| dispatch_pthread_root_queue_context_t pqc = qc->dgq_ctxt; |
| if (fastpath(pqc->dpq_thread_mediator.do_vtable)) { |
| while (dispatch_semaphore_signal(&pqc->dpq_thread_mediator)) { |
| _dispatch_root_queue_debug("signaled sleeping worker for " |
| "global queue: %p", dq); |
| if (!--remaining) { |
| return; |
| } |
| } |
| } |
| |
| bool overcommit = dq->dq_priority & DISPATCH_PRIORITY_FLAG_OVERCOMMIT; |
| if (overcommit) { |
| os_atomic_add2o(qc, dgq_pending, remaining, relaxed); |
| } else { |
| if (!os_atomic_cmpxchg2o(qc, dgq_pending, 0, remaining, relaxed)) { |
| _dispatch_root_queue_debug("worker thread request still pending for " |
| "global queue: %p", dq); |
| return; |
| } |
| } |
| |
| int32_t can_request, t_count; |
| // seq_cst with atomic store to tail <rdar://problem/16932833> |
| t_count = os_atomic_load2o(qc, dgq_thread_pool_size, ordered); |
| do { |
| can_request = t_count < floor ? 0 : t_count - floor; |
| if (remaining > can_request) { |
| _dispatch_root_queue_debug("pthread pool reducing request from %d to %d", |
| remaining, can_request); |
| os_atomic_sub2o(qc, dgq_pending, remaining - can_request, relaxed); |
| remaining = can_request; |
| } |
| if (remaining == 0) { |
| _dispatch_root_queue_debug("pthread pool is full for root queue: " |
| "%p", dq); |
| return; |
| } |
| } while (!os_atomic_cmpxchgvw2o(qc, dgq_thread_pool_size, t_count, |
| t_count - remaining, &t_count, acquire)); |
| |
| #if defined(_WIN32) |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| if (slowpath(dq == &_dispatch_mgr_root_queue)) { |
| _dispatch_mgr_root_queue_init(); |
| } |
| #endif |
| do { |
| _dispatch_retain(dq); // released in _dispatch_worker_thread |
| #if DISPATCH_DEBUG |
| unsigned dwStackSize = 0; |
| #else |
| unsigned dwStackSize = 64 * 1024; |
| #endif |
| uintptr_t hThread = 0; |
| while (!(hThread = _beginthreadex(NULL, dwStackSize, _dispatch_worker_thread_thunk, dq, STACK_SIZE_PARAM_IS_A_RESERVATION, NULL))) { |
| if (errno != EAGAIN) { |
| (void)dispatch_assume(hThread); |
| } |
| _dispatch_temporary_resource_shortage(); |
| } |
| if (_dispatch_mgr_sched.prio > _dispatch_mgr_sched.default_prio) { |
| (void)dispatch_assume_zero(SetThreadPriority((HANDLE)hThread, _dispatch_mgr_sched.prio) == TRUE); |
| } |
| CloseHandle((HANDLE)hThread); |
| } while (--remaining); |
| #else |
| pthread_attr_t *attr = &pqc->dpq_thread_attr; |
| pthread_t tid, *pthr = &tid; |
| #if DISPATCH_USE_MGR_THREAD && DISPATCH_ENABLE_PTHREAD_ROOT_QUEUES |
| if (slowpath(dq == &_dispatch_mgr_root_queue)) { |
| pthr = _dispatch_mgr_root_queue_init(); |
| } |
| #endif |
| do { |
| _dispatch_retain(dq); // released in _dispatch_worker_thread |
| while ((r = pthread_create(pthr, attr, _dispatch_worker_thread, dq))) { |
| if (r != EAGAIN) { |
| (void)dispatch_assume_zero(r); |
| } |
| _dispatch_temporary_resource_shortage(); |
| } |
| } while (--remaining); |
| #endif |
| #endif // DISPATCH_USE_PTHREAD_POOL |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_global_queue_poke(dispatch_queue_t dq, int n, int floor) |
| { |
| if (!_dispatch_queue_class_probe(dq)) { |
| return; |
| } |
| #if DISPATCH_USE_WORKQUEUES |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| if ( |
| #if DISPATCH_USE_PTHREAD_POOL |
| (qc->dgq_kworkqueue != (void*)(~0ul)) && |
| #endif |
| !os_atomic_cmpxchg2o(qc, dgq_pending, 0, n, relaxed)) { |
| _dispatch_root_queue_debug("worker thread request still pending for " |
| "global queue: %p", dq); |
| return; |
| } |
| #endif // DISPATCH_USE_WORKQUEUES |
| return _dispatch_global_queue_poke_slow(dq, n, floor); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_drain |
| |
| void |
| _dispatch_continuation_pop(dispatch_object_t dou, dispatch_invoke_context_t dic, |
| dispatch_invoke_flags_t flags, dispatch_queue_t dq) |
| { |
| _dispatch_continuation_pop_inline(dou, dic, flags, dq); |
| } |
| |
| void |
| _dispatch_continuation_invoke(dispatch_object_t dou, voucher_t ov, |
| dispatch_invoke_flags_t flags) |
| { |
| _dispatch_continuation_invoke_inline(dou, ov, flags); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_return_to_kernel(void) |
| { |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| if (unlikely(_dispatch_get_wlh() == DISPATCH_WLH_ANON)) { |
| _dispatch_clear_return_to_kernel(); |
| } else { |
| _dispatch_event_loop_drain(KEVENT_FLAG_IMMEDIATE); |
| } |
| #endif |
| } |
| |
| void |
| _dispatch_poll_for_events_4launchd(void) |
| { |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| if (_dispatch_get_wlh()) { |
| dispatch_assert(_dispatch_deferred_items_get()->ddi_wlh_servicing); |
| _dispatch_event_loop_drain(KEVENT_FLAG_IMMEDIATE); |
| } |
| #endif |
| } |
| |
| #if HAVE_PTHREAD_WORKQUEUE_NARROWING |
| static os_atomic(uint64_t) _dispatch_narrowing_deadlines[DISPATCH_QOS_MAX]; |
| #if !DISPATCH_TIME_UNIT_USES_NANOSECONDS |
| static uint64_t _dispatch_narrow_check_interval_cache; |
| #endif |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline uint64_t |
| _dispatch_narrow_check_interval(void) |
| { |
| #if DISPATCH_TIME_UNIT_USES_NANOSECONDS |
| return 50 * NSEC_PER_MSEC; |
| #else |
| if (_dispatch_narrow_check_interval_cache == 0) { |
| _dispatch_narrow_check_interval_cache = |
| _dispatch_time_nano2mach(50 * NSEC_PER_MSEC); |
| } |
| return _dispatch_narrow_check_interval_cache; |
| #endif |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_queue_drain_init_narrowing_check_deadline(dispatch_invoke_context_t dic, |
| dispatch_priority_t pri) |
| { |
| if (_dispatch_priority_qos(pri) && |
| !(pri & DISPATCH_PRIORITY_FLAG_OVERCOMMIT)) { |
| dic->dic_next_narrow_check = _dispatch_approximate_time() + |
| _dispatch_narrow_check_interval(); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| static bool |
| _dispatch_queue_drain_should_narrow_slow(uint64_t now, |
| dispatch_invoke_context_t dic) |
| { |
| if (dic->dic_next_narrow_check != DISPATCH_THREAD_IS_NARROWING) { |
| pthread_priority_t pp = _dispatch_get_priority(); |
| dispatch_qos_t qos = _dispatch_qos_from_pp(pp); |
| if (unlikely(!qos || qos > countof(_dispatch_narrowing_deadlines))) { |
| DISPATCH_CLIENT_CRASH(pp, "Thread QoS corruption"); |
| } |
| size_t idx = qos - 1; // no entry needed for DISPATCH_QOS_UNSPECIFIED |
| os_atomic(uint64_t) *deadline = &_dispatch_narrowing_deadlines[idx]; |
| uint64_t oldval, newval = now + _dispatch_narrow_check_interval(); |
| |
| dic->dic_next_narrow_check = newval; |
| os_atomic_rmw_loop(deadline, oldval, newval, relaxed, { |
| if (now < oldval) { |
| os_atomic_rmw_loop_give_up(return false); |
| } |
| }); |
| |
| if (!_pthread_workqueue_should_narrow(pp)) { |
| return false; |
| } |
| dic->dic_next_narrow_check = DISPATCH_THREAD_IS_NARROWING; |
| } |
| return true; |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_queue_drain_should_narrow(dispatch_invoke_context_t dic) |
| { |
| uint64_t next_check = dic->dic_next_narrow_check; |
| if (unlikely(next_check)) { |
| uint64_t now = _dispatch_approximate_time(); |
| if (unlikely(next_check < now)) { |
| return _dispatch_queue_drain_should_narrow_slow(now, dic); |
| } |
| } |
| return false; |
| } |
| #else |
| #define _dispatch_queue_drain_init_narrowing_check_deadline(rq, dic) ((void)0) |
| #define _dispatch_queue_drain_should_narrow(dic) false |
| #endif |
| |
| /* |
| * Drain comes in 2 flavours (serial/concurrent) and 2 modes |
| * (redirecting or not). |
| * |
| * Serial |
| * ~~~~~~ |
| * Serial drain is about serial queues (width == 1). It doesn't support |
| * the redirecting mode, which doesn't make sense, and treats all continuations |
| * as barriers. Bookkeeping is minimal in serial flavour, most of the loop |
| * is optimized away. |
| * |
| * Serial drain stops if the width of the queue grows to larger than 1. |
| * Going through a serial drain prevents any recursive drain from being |
| * redirecting. |
| * |
| * Concurrent |
| * ~~~~~~~~~~ |
| * When in non-redirecting mode (meaning one of the target queues is serial), |
| * non-barriers and barriers alike run in the context of the drain thread. |
| * Slow non-barrier items are still all signaled so that they can make progress |
| * toward the dispatch_sync() that will serialize them all . |
| * |
| * In redirecting mode, non-barrier work items are redirected downward. |
| * |
| * Concurrent drain stops if the width of the queue becomes 1, so that the |
| * queue drain moves to the more efficient serial mode. |
| */ |
| DISPATCH_ALWAYS_INLINE |
| static dispatch_queue_wakeup_target_t |
| _dispatch_queue_drain(dispatch_queue_t dq, dispatch_invoke_context_t dic, |
| dispatch_invoke_flags_t flags, uint64_t *owned_ptr, bool serial_drain) |
| { |
| dispatch_queue_t orig_tq = dq->do_targetq; |
| dispatch_thread_frame_s dtf; |
| struct dispatch_object_s *dc = NULL, *next_dc; |
| uint64_t dq_state, owned = *owned_ptr; |
| |
| if (unlikely(!dq->dq_items_tail)) return NULL; |
| |
| _dispatch_thread_frame_push(&dtf, dq); |
| if (serial_drain || _dq_state_is_in_barrier(owned)) { |
| // we really own `IN_BARRIER + dq->dq_width * WIDTH_INTERVAL` |
| // but width can change while draining barrier work items, so we only |
| // convert to `dq->dq_width * WIDTH_INTERVAL` when we drop `IN_BARRIER` |
| owned = DISPATCH_QUEUE_IN_BARRIER; |
| } else { |
| owned &= DISPATCH_QUEUE_WIDTH_MASK; |
| } |
| |
| dc = _dispatch_queue_head(dq); |
| goto first_iteration; |
| |
| for (;;) { |
| dc = next_dc; |
| if (unlikely(dic->dic_deferred)) { |
| goto out_with_deferred_compute_owned; |
| } |
| if (unlikely(_dispatch_needs_to_return_to_kernel())) { |
| _dispatch_return_to_kernel(); |
| } |
| if (unlikely(!dc)) { |
| if (!dq->dq_items_tail) { |
| break; |
| } |
| dc = _dispatch_queue_head(dq); |
| } |
| if (unlikely(serial_drain != (dq->dq_width == 1))) { |
| break; |
| } |
| if (unlikely(_dispatch_queue_drain_should_narrow(dic))) { |
| break; |
| } |
| |
| first_iteration: |
| dq_state = os_atomic_load(&dq->dq_state, relaxed); |
| if (unlikely(_dq_state_is_suspended(dq_state))) { |
| break; |
| } |
| if (unlikely(orig_tq != dq->do_targetq)) { |
| break; |
| } |
| |
| if (serial_drain || _dispatch_object_is_barrier(dc)) { |
| if (!serial_drain && owned != DISPATCH_QUEUE_IN_BARRIER) { |
| if (!_dispatch_queue_try_upgrade_full_width(dq, owned)) { |
| goto out_with_no_width; |
| } |
| owned = DISPATCH_QUEUE_IN_BARRIER; |
| } |
| next_dc = _dispatch_queue_next(dq, dc); |
| if (_dispatch_object_is_sync_waiter(dc)) { |
| owned = 0; |
| dic->dic_deferred = dc; |
| goto out_with_deferred; |
| } |
| } else { |
| if (owned == DISPATCH_QUEUE_IN_BARRIER) { |
| // we just ran barrier work items, we have to make their |
| // effect visible to other sync work items on other threads |
| // that may start coming in after this point, hence the |
| // release barrier |
| os_atomic_xor2o(dq, dq_state, owned, release); |
| owned = dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| } else if (unlikely(owned == 0)) { |
| if (_dispatch_object_is_sync_waiter(dc)) { |
| // sync "readers" don't observe the limit |
| _dispatch_queue_reserve_sync_width(dq); |
| } else if (!_dispatch_queue_try_acquire_async(dq)) { |
| goto out_with_no_width; |
| } |
| owned = DISPATCH_QUEUE_WIDTH_INTERVAL; |
| } |
| |
| next_dc = _dispatch_queue_next(dq, dc); |
| if (_dispatch_object_is_sync_waiter(dc)) { |
| owned -= DISPATCH_QUEUE_WIDTH_INTERVAL; |
| _dispatch_sync_waiter_redirect_or_wake(dq, |
| DISPATCH_SYNC_WAITER_NO_UNLOCK, dc); |
| continue; |
| } |
| |
| if (flags & DISPATCH_INVOKE_REDIRECTING_DRAIN) { |
| owned -= DISPATCH_QUEUE_WIDTH_INTERVAL; |
| _dispatch_continuation_redirect(dq, dc); |
| continue; |
| } |
| } |
| |
| _dispatch_continuation_pop_inline(dc, dic, flags, dq); |
| } |
| |
| if (owned == DISPATCH_QUEUE_IN_BARRIER) { |
| // if we're IN_BARRIER we really own the full width too |
| owned += dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| } |
| if (dc) { |
| owned = _dispatch_queue_adjust_owned(dq, owned, dc); |
| } |
| *owned_ptr &= DISPATCH_QUEUE_ENQUEUED | DISPATCH_QUEUE_ENQUEUED_ON_MGR; |
| *owned_ptr |= owned; |
| _dispatch_thread_frame_pop(&dtf); |
| return dc ? dq->do_targetq : NULL; |
| |
| out_with_no_width: |
| *owned_ptr &= DISPATCH_QUEUE_ENQUEUED | DISPATCH_QUEUE_ENQUEUED_ON_MGR; |
| _dispatch_thread_frame_pop(&dtf); |
| return DISPATCH_QUEUE_WAKEUP_WAIT_FOR_EVENT; |
| |
| out_with_deferred_compute_owned: |
| if (serial_drain) { |
| owned = DISPATCH_QUEUE_IN_BARRIER + DISPATCH_QUEUE_WIDTH_INTERVAL; |
| } else { |
| if (owned == DISPATCH_QUEUE_IN_BARRIER) { |
| // if we're IN_BARRIER we really own the full width too |
| owned += dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| } |
| if (dc) { |
| owned = _dispatch_queue_adjust_owned(dq, owned, dc); |
| } |
| } |
| out_with_deferred: |
| *owned_ptr &= DISPATCH_QUEUE_ENQUEUED | DISPATCH_QUEUE_ENQUEUED_ON_MGR; |
| *owned_ptr |= owned; |
| if (unlikely(flags & DISPATCH_INVOKE_DISALLOW_SYNC_WAITERS)) { |
| DISPATCH_INTERNAL_CRASH(dc, |
| "Deferred continuation on source, mach channel or mgr"); |
| } |
| _dispatch_thread_frame_pop(&dtf); |
| return dq->do_targetq; |
| } |
| |
| DISPATCH_NOINLINE |
| static dispatch_queue_wakeup_target_t |
| _dispatch_queue_concurrent_drain(dispatch_queue_t dq, |
| dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags, |
| uint64_t *owned) |
| { |
| return _dispatch_queue_drain(dq, dic, flags, owned, false); |
| } |
| |
| DISPATCH_NOINLINE |
| dispatch_queue_wakeup_target_t |
| _dispatch_queue_serial_drain(dispatch_queue_t dq, dispatch_invoke_context_t dic, |
| dispatch_invoke_flags_t flags, uint64_t *owned) |
| { |
| flags &= ~(dispatch_invoke_flags_t)DISPATCH_INVOKE_REDIRECTING_DRAIN; |
| return _dispatch_queue_drain(dq, dic, flags, owned, true); |
| } |
| |
| #if DISPATCH_COCOA_COMPAT |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_main_queue_update_priority_from_thread(void) |
| { |
| dispatch_queue_t dq = &_dispatch_main_q; |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| mach_port_t owner = _dq_state_drain_owner(dq_state); |
| |
| dispatch_priority_t main_pri = |
| _dispatch_priority_from_pp_strip_flags(_dispatch_get_priority()); |
| dispatch_qos_t main_qos = _dispatch_priority_qos(main_pri); |
| dispatch_qos_t max_qos = _dq_state_max_qos(dq_state); |
| dispatch_qos_t old_qos = _dispatch_priority_qos(dq->dq_priority); |
| |
| // the main thread QoS was adjusted by someone else, learn the new QoS |
| // and reinitialize _dispatch_main_q.dq_priority |
| dq->dq_priority = _dispatch_priority_with_override_qos(main_pri, main_qos); |
| |
| if (old_qos < max_qos && main_qos == DISPATCH_QOS_UNSPECIFIED) { |
| // main thread is opted out of QoS and we had an override |
| return _dispatch_thread_override_end(owner, dq); |
| } |
| |
| if (old_qos < max_qos && max_qos <= main_qos) { |
| // main QoS was raised, and we had an override which is now useless |
| return _dispatch_thread_override_end(owner, dq); |
| } |
| |
| if (main_qos < max_qos && max_qos <= old_qos) { |
| // main thread QoS was lowered, and we actually need an override |
| pthread_priority_t pp = _dispatch_qos_to_pp(max_qos); |
| return _dispatch_thread_override_start(owner, pp, dq); |
| } |
| } |
| |
| static void |
| _dispatch_main_queue_drain(void) |
| { |
| dispatch_queue_t dq = &_dispatch_main_q; |
| dispatch_thread_frame_s dtf; |
| |
| if (!dq->dq_items_tail) { |
| return; |
| } |
| |
| _dispatch_perfmon_start_notrace(); |
| if (!fastpath(_dispatch_queue_is_thread_bound(dq))) { |
| DISPATCH_CLIENT_CRASH(0, "_dispatch_main_queue_callback_4CF called" |
| " after dispatch_main()"); |
| } |
| uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (unlikely(!_dq_state_drain_locked_by_self(dq_state))) { |
| DISPATCH_CLIENT_CRASH((uintptr_t)dq_state, |
| "_dispatch_main_queue_callback_4CF called" |
| " from the wrong thread"); |
| } |
| |
| dispatch_once_f(&_dispatch_main_q_handle_pred, dq, |
| _dispatch_runloop_queue_handle_init); |
| |
| // <rdar://problem/23256682> hide the frame chaining when CFRunLoop |
| // drains the main runloop, as this should not be observable that way |
| _dispatch_adopt_wlh_anon(); |
| _dispatch_thread_frame_push_and_rebase(&dtf, dq, NULL); |
| |
| pthread_priority_t pp = _dispatch_get_priority(); |
| dispatch_priority_t pri = _dispatch_priority_from_pp(pp); |
| dispatch_qos_t qos = _dispatch_priority_qos(pri); |
| voucher_t voucher = _voucher_copy(); |
| |
| if (unlikely(qos != _dispatch_priority_qos(dq->dq_priority))) { |
| _dispatch_main_queue_update_priority_from_thread(); |
| } |
| dispatch_priority_t old_dbp = _dispatch_set_basepri(pri); |
| _dispatch_set_basepri_override_qos(DISPATCH_QOS_SATURATED); |
| |
| dispatch_invoke_context_s dic = { }; |
| struct dispatch_object_s *dc, *next_dc, *tail; |
| dc = os_mpsc_capture_snapshot(dq, dq_items, &tail); |
| do { |
| next_dc = os_mpsc_pop_snapshot_head(dc, tail, do_next); |
| _dispatch_continuation_pop_inline(dc, &dic, DISPATCH_INVOKE_NONE, dq); |
| } while ((dc = next_dc)); |
| |
| dx_wakeup(dq, 0, 0); |
| _dispatch_voucher_debug("main queue restore", voucher); |
| _dispatch_reset_basepri(old_dbp); |
| _dispatch_reset_basepri_override(); |
| _dispatch_reset_priority_and_voucher(pp, voucher); |
| _dispatch_thread_frame_pop(&dtf); |
| _dispatch_reset_wlh(); |
| _dispatch_force_cache_cleanup(); |
| _dispatch_perfmon_end_notrace(); |
| } |
| |
| static bool |
| _dispatch_runloop_queue_drain_one(dispatch_queue_t dq) |
| { |
| if (!dq->dq_items_tail) { |
| return false; |
| } |
| _dispatch_perfmon_start_notrace(); |
| dispatch_thread_frame_s dtf; |
| bool should_reset_wlh = _dispatch_adopt_wlh_anon_recurse(); |
| _dispatch_thread_frame_push(&dtf, dq); |
| pthread_priority_t pp = _dispatch_get_priority(); |
| dispatch_priority_t pri = _dispatch_priority_from_pp(pp); |
| voucher_t voucher = _voucher_copy(); |
| dispatch_priority_t old_dbp = _dispatch_set_basepri(pri); |
| _dispatch_set_basepri_override_qos(DISPATCH_QOS_SATURATED); |
| |
| dispatch_invoke_context_s dic = { }; |
| struct dispatch_object_s *dc, *next_dc; |
| dc = _dispatch_queue_head(dq); |
| next_dc = _dispatch_queue_next(dq, dc); |
| _dispatch_continuation_pop_inline(dc, &dic, DISPATCH_INVOKE_NONE, dq); |
| |
| if (!next_dc) { |
| dx_wakeup(dq, 0, 0); |
| } |
| |
| _dispatch_voucher_debug("runloop queue restore", voucher); |
| _dispatch_reset_basepri(old_dbp); |
| _dispatch_reset_basepri_override(); |
| _dispatch_reset_priority_and_voucher(pp, voucher); |
| _dispatch_thread_frame_pop(&dtf); |
| if (should_reset_wlh) _dispatch_reset_wlh(); |
| _dispatch_force_cache_cleanup(); |
| _dispatch_perfmon_end_notrace(); |
| return next_dc; |
| } |
| #endif |
| |
| void |
| _dispatch_mgr_queue_drain(void) |
| { |
| const dispatch_invoke_flags_t flags = DISPATCH_INVOKE_MANAGER_DRAIN; |
| dispatch_invoke_context_s dic = { }; |
| dispatch_queue_t dq = &_dispatch_mgr_q; |
| uint64_t owned = DISPATCH_QUEUE_SERIAL_DRAIN_OWNED; |
| |
| if (dq->dq_items_tail) { |
| _dispatch_perfmon_start(); |
| _dispatch_set_basepri_override_qos(DISPATCH_QOS_SATURATED); |
| if (slowpath(_dispatch_queue_serial_drain(dq, &dic, flags, &owned))) { |
| DISPATCH_INTERNAL_CRASH(0, "Interrupted drain on manager queue"); |
| } |
| _dispatch_voucher_debug("mgr queue clear", NULL); |
| _voucher_clear(); |
| _dispatch_reset_basepri_override(); |
| _dispatch_perfmon_end(perfmon_thread_manager); |
| } |
| |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| if (!_dispatch_kevent_workqueue_enabled) |
| #endif |
| { |
| _dispatch_force_cache_cleanup(); |
| } |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_invoke |
| |
| void |
| _dispatch_queue_drain_sync_waiter(dispatch_queue_t dq, |
| dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags, |
| uint64_t owned) |
| { |
| struct dispatch_object_s *dc = dic->dic_deferred; |
| dispatch_assert(_dispatch_object_is_sync_waiter(dc)); |
| dic->dic_deferred = NULL; |
| if (flags & DISPATCH_INVOKE_WLH) { |
| // Leave the enqueued bit in place, completion of the last sync waiter |
| // in the handoff chain is responsible for dequeuing |
| // |
| // We currently have a +2 to consume, but we need to keep a +1 |
| // for the thread request |
| dispatch_assert(_dq_state_is_enqueued_on_target(owned)); |
| dispatch_assert(!_dq_state_is_enqueued_on_manager(owned)); |
| owned &= ~DISPATCH_QUEUE_ENQUEUED; |
| _dispatch_release_no_dispose(dq); |
| } else { |
| // The sync waiter must own a reference |
| _dispatch_release_2_no_dispose(dq); |
| } |
| return _dispatch_sync_waiter_redirect_or_wake(dq, owned, dc); |
| } |
| |
| void |
| _dispatch_queue_finalize_activation(dispatch_queue_t dq, |
| DISPATCH_UNUSED bool *allow_resume) |
| { |
| dispatch_queue_t tq = dq->do_targetq; |
| _dispatch_queue_priority_inherit_from_target(dq, tq); |
| _dispatch_queue_inherit_wlh_from_target(dq, tq); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline dispatch_queue_wakeup_target_t |
| dispatch_queue_invoke2(dispatch_queue_t dq, dispatch_invoke_context_t dic, |
| dispatch_invoke_flags_t flags, uint64_t *owned) |
| { |
| dispatch_queue_t otq = dq->do_targetq; |
| dispatch_queue_t cq = _dispatch_queue_get_current(); |
| |
| if (slowpath(cq != otq)) { |
| return otq; |
| } |
| if (dq->dq_width == 1) { |
| return _dispatch_queue_serial_drain(dq, dic, flags, owned); |
| } |
| return _dispatch_queue_concurrent_drain(dq, dic, flags, owned); |
| } |
| |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| DISPATCH_NOINLINE |
| void |
| _dispatch_queue_invoke(dispatch_queue_t dq, dispatch_invoke_context_t dic, |
| dispatch_invoke_flags_t flags) |
| { |
| _dispatch_queue_class_invoke(dq, dic, flags, 0, dispatch_queue_invoke2); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_queue_class_wakeup |
| |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| void |
| _dispatch_queue_override_invoke(dispatch_continuation_t dc, |
| dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags) |
| { |
| dispatch_queue_t old_rq = _dispatch_queue_get_current(); |
| dispatch_queue_t assumed_rq = dc->dc_other; |
| dispatch_priority_t old_dp; |
| voucher_t ov = DISPATCH_NO_VOUCHER; |
| dispatch_object_t dou; |
| |
| dou._do = dc->dc_data; |
| old_dp = _dispatch_root_queue_identity_assume(assumed_rq); |
| if (dc_type(dc) == DISPATCH_CONTINUATION_TYPE(OVERRIDE_STEALING)) { |
| flags |= DISPATCH_INVOKE_STEALING; |
| } else { |
| // balance the fake continuation push in |
| // _dispatch_root_queue_push_override |
| _dispatch_trace_continuation_pop(assumed_rq, dou._do); |
| } |
| _dispatch_continuation_pop_forwarded(dc, ov, DISPATCH_OBJ_CONSUME_BIT, { |
| if (_dispatch_object_has_vtable(dou._do)) { |
| dx_invoke(dou._do, dic, flags); |
| } else { |
| _dispatch_continuation_invoke_inline(dou, ov, flags); |
| } |
| }); |
| _dispatch_reset_basepri(old_dp); |
| _dispatch_queue_set_current(old_rq); |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_root_queue_push_needs_override(dispatch_queue_t rq, |
| dispatch_qos_t qos) |
| { |
| dispatch_qos_t rqos = _dispatch_priority_qos(rq->dq_priority); |
| bool defaultqueue = rq->dq_priority & DISPATCH_PRIORITY_FLAG_DEFAULTQUEUE; |
| |
| if (unlikely(!rqos)) return false; |
| |
| return defaultqueue ? qos && qos != rqos : qos > rqos; |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_root_queue_push_queue_override_needed(dispatch_queue_t rq, |
| dispatch_qos_t qos) |
| { |
| // for root queues, the override is the guaranteed minimum override level |
| return qos > _dispatch_priority_override_qos(rq->dq_priority); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_root_queue_push_override(dispatch_queue_t orig_rq, |
| dispatch_object_t dou, dispatch_qos_t qos) |
| { |
| bool overcommit = orig_rq->dq_priority & DISPATCH_PRIORITY_FLAG_OVERCOMMIT; |
| dispatch_queue_t rq = _dispatch_get_root_queue(qos, overcommit); |
| dispatch_continuation_t dc = dou._dc; |
| |
| if (_dispatch_object_is_redirection(dc)) { |
| // no double-wrap is needed, _dispatch_async_redirect_invoke will do |
| // the right thing |
| dc->dc_func = (void *)orig_rq; |
| } else { |
| dc = _dispatch_continuation_alloc(); |
| dc->do_vtable = DC_VTABLE(OVERRIDE_OWNING); |
| // fake that we queued `dou` on `orig_rq` for introspection purposes |
| _dispatch_trace_continuation_push(orig_rq, dou); |
| dc->dc_ctxt = dc; |
| dc->dc_other = orig_rq; |
| dc->dc_data = dou._do; |
| dc->dc_priority = DISPATCH_NO_PRIORITY; |
| dc->dc_voucher = DISPATCH_NO_VOUCHER; |
| } |
| _dispatch_root_queue_push_inline(rq, dc, dc, 1); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_root_queue_push_override_stealer(dispatch_queue_t orig_rq, |
| dispatch_queue_t dq, dispatch_qos_t qos) |
| { |
| bool overcommit = orig_rq->dq_priority & DISPATCH_PRIORITY_FLAG_OVERCOMMIT; |
| dispatch_queue_t rq = _dispatch_get_root_queue(qos, overcommit); |
| dispatch_continuation_t dc = _dispatch_continuation_alloc(); |
| |
| dc->do_vtable = DC_VTABLE(OVERRIDE_STEALING); |
| _dispatch_retain_2(dq); |
| dc->dc_func = NULL; |
| dc->dc_ctxt = dc; |
| dc->dc_other = orig_rq; |
| dc->dc_data = dq; |
| dc->dc_priority = DISPATCH_NO_PRIORITY; |
| dc->dc_voucher = DISPATCH_NO_VOUCHER; |
| _dispatch_root_queue_push_inline(rq, dc, dc, 1); |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_class_wakeup_with_override_slow(dispatch_queue_t dq, |
| uint64_t dq_state, dispatch_wakeup_flags_t flags) |
| { |
| dispatch_qos_t oqos, qos = _dq_state_max_qos(dq_state); |
| dispatch_queue_t tq; |
| bool locked; |
| |
| if (_dq_state_is_base_anon(dq_state)) { |
| mach_port_t owner = _dq_state_drain_owner(dq_state); |
| if (owner) { |
| (void)_dispatch_wqthread_override_start_check_owner(owner, qos, |
| &dq->dq_state_lock); |
| goto out; |
| } |
| } |
| |
| tq = dq->do_targetq; |
| |
| if (likely(!_dispatch_queue_is_legacy(dq))) { |
| locked = false; |
| } else if (_dispatch_is_in_root_queues_array(tq)) { |
| // avoid locking when we recognize the target queue as a global root |
| // queue it is gross, but is a very common case. The locking isn't |
| // needed because these target queues cannot go away. |
| locked = false; |
| } else if (_dispatch_queue_sidelock_trylock(dq, qos)) { |
| // <rdar://problem/17735825> to traverse the tq chain safely we must |
| // lock it to ensure it cannot change |
| locked = true; |
| tq = dq->do_targetq; |
| _dispatch_ktrace1(DISPATCH_PERF_mutable_target, dq); |
| } else { |
| // |
| // Leading to being there, the current thread has: |
| // 1. enqueued an object on `dq` |
| // 2. raised the max_qos value, set RECEIVED_OVERRIDE on `dq` |
| // and didn't see an owner |
| // 3. tried and failed to acquire the side lock |
| // |
| // The side lock owner can only be one of three things: |
| // |
| // - The suspend/resume side count code. Besides being unlikely, |
| // it means that at this moment the queue is actually suspended, |
| // which transfers the responsibility of applying the override to |
| // the eventual dispatch_resume(). |
| // |
| // - A dispatch_set_target_queue() call. The fact that we saw no `owner` |
| // means that the trysync it does wasn't being drained when (2) |
| // happened which can only be explained by one of these interleavings: |
| // |
| // o `dq` became idle between when the object queued in (1) ran and |
| // the set_target_queue call and we were unlucky enough that our |
| // step (2) happened while this queue was idle. There is no reason |
| // to override anything anymore, the queue drained to completion |
| // while we were preempted, our job is done. |
| // |
| // o `dq` is queued but not draining during (1-2), then when we try |
| // to lock at (3) the queue is now draining a set_target_queue. |
| // This drainer must have seen the effects of (2) and that guy has |
| // applied our override. Our job is done. |
| // |
| // - Another instance of _dispatch_queue_class_wakeup_with_override(), |
| // which is fine because trylock leaves a hint that we failed our |
| // trylock, causing the tryunlock below to fail and reassess whether |
| // a better override needs to be applied. |
| // |
| _dispatch_ktrace1(DISPATCH_PERF_mutable_target, dq); |
| goto out; |
| } |
| |
| apply_again: |
| if (dx_hastypeflag(tq, QUEUE_ROOT)) { |
| if (_dispatch_root_queue_push_queue_override_needed(tq, qos)) { |
| _dispatch_root_queue_push_override_stealer(tq, dq, qos); |
| } |
| } else if (_dispatch_queue_need_override(tq, qos)) { |
| dx_wakeup(tq, qos, 0); |
| } |
| while (unlikely(locked && !_dispatch_queue_sidelock_tryunlock(dq))) { |
| // rdar://problem/24081326 |
| // |
| // Another instance of _dispatch_queue_class_wakeup_with_override() |
| // tried to acquire the side lock while we were running, and could have |
| // had a better override than ours to apply. |
| // |
| oqos = _dq_state_max_qos(os_atomic_load2o(dq, dq_state, relaxed)); |
| if (oqos > qos) { |
| qos = oqos; |
| // The other instance had a better priority than ours, override |
| // our thread, and apply the override that wasn't applied to `dq` |
| // because of us. |
| goto apply_again; |
| } |
| } |
| |
| out: |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| } |
| |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline void |
| _dispatch_queue_class_wakeup_with_override(dispatch_queue_t dq, |
| uint64_t dq_state, dispatch_wakeup_flags_t flags) |
| { |
| dispatch_assert(_dq_state_should_override(dq_state)); |
| |
| return _dispatch_queue_class_wakeup_with_override_slow(dq, dq_state, flags); |
| } |
| #endif // HAVE_PTHREAD_WORKQUEUE_QOS |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_root_queue_push(dispatch_queue_t rq, dispatch_object_t dou, |
| dispatch_qos_t qos) |
| { |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| dispatch_deferred_items_t ddi = _dispatch_deferred_items_get(); |
| if (unlikely(ddi && ddi->ddi_can_stash)) { |
| dispatch_object_t old_dou = ddi->ddi_stashed_dou; |
| dispatch_priority_t rq_overcommit; |
| rq_overcommit = rq->dq_priority & DISPATCH_PRIORITY_FLAG_OVERCOMMIT; |
| |
| if (likely(!old_dou._do || rq_overcommit)) { |
| dispatch_queue_t old_rq = ddi->ddi_stashed_rq; |
| dispatch_qos_t old_qos = ddi->ddi_stashed_qos; |
| ddi->ddi_stashed_rq = rq; |
| ddi->ddi_stashed_dou = dou; |
| ddi->ddi_stashed_qos = qos; |
| _dispatch_debug("deferring item %p, rq %p, qos %d", |
| dou._do, rq, qos); |
| if (rq_overcommit) { |
| ddi->ddi_can_stash = false; |
| } |
| if (likely(!old_dou._do)) { |
| return; |
| } |
| // push the previously stashed item |
| qos = old_qos; |
| rq = old_rq; |
| dou = old_dou; |
| } |
| } |
| #endif |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| if (_dispatch_root_queue_push_needs_override(rq, qos)) { |
| return _dispatch_root_queue_push_override(rq, dou, qos); |
| } |
| #else |
| (void)qos; |
| #endif |
| _dispatch_root_queue_push_inline(rq, dou, dou, 1); |
| } |
| |
| void |
| _dispatch_root_queue_wakeup(dispatch_queue_t dq, |
| DISPATCH_UNUSED dispatch_qos_t qos, dispatch_wakeup_flags_t flags) |
| { |
| if (!(flags & DISPATCH_WAKEUP_BLOCK_WAIT)) { |
| DISPATCH_INTERNAL_CRASH(dq->dq_priority, |
| "Don't try to wake up or override a root queue"); |
| } |
| if (flags & DISPATCH_WAKEUP_CONSUME_2) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_queue_push(dispatch_queue_t dq, dispatch_object_t dou, |
| dispatch_qos_t qos) |
| { |
| _dispatch_queue_push_inline(dq, dou, qos); |
| } |
| |
| DISPATCH_NOINLINE |
| void |
| _dispatch_queue_class_wakeup(dispatch_queue_t dq, dispatch_qos_t qos, |
| dispatch_wakeup_flags_t flags, dispatch_queue_wakeup_target_t target) |
| { |
| dispatch_assert(target != DISPATCH_QUEUE_WAKEUP_WAIT_FOR_EVENT); |
| |
| if (target && !(flags & DISPATCH_WAKEUP_CONSUME_2)) { |
| _dispatch_retain_2(dq); |
| flags |= DISPATCH_WAKEUP_CONSUME_2; |
| } |
| |
| if (unlikely(flags & DISPATCH_WAKEUP_BARRIER_COMPLETE)) { |
| // |
| // _dispatch_queue_class_barrier_complete() is about what both regular |
| // queues and sources needs to evaluate, but the former can have sync |
| // handoffs to perform which _dispatch_queue_class_barrier_complete() |
| // doesn't handle, only _dispatch_queue_barrier_complete() does. |
| // |
| // _dispatch_queue_wakeup() is the one for plain queues that calls |
| // _dispatch_queue_barrier_complete(), and this is only taken for non |
| // queue types. |
| // |
| dispatch_assert(dx_metatype(dq) != _DISPATCH_QUEUE_TYPE); |
| return _dispatch_queue_class_barrier_complete(dq, qos, flags, target, |
| DISPATCH_QUEUE_SERIAL_DRAIN_OWNED); |
| } |
| |
| if (target) { |
| uint64_t old_state, new_state, enqueue = DISPATCH_QUEUE_ENQUEUED; |
| if (target == DISPATCH_QUEUE_WAKEUP_MGR) { |
| enqueue = DISPATCH_QUEUE_ENQUEUED_ON_MGR; |
| } |
| qos = _dispatch_queue_override_qos(dq, qos); |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, release, { |
| new_state = _dq_state_merge_qos(old_state, qos); |
| if (likely(!_dq_state_is_suspended(old_state) && |
| !_dq_state_is_enqueued(old_state) && |
| (!_dq_state_drain_locked(old_state) || |
| (enqueue != DISPATCH_QUEUE_ENQUEUED_ON_MGR && |
| _dq_state_is_base_wlh(old_state))))) { |
| new_state |= enqueue; |
| } |
| if (flags & DISPATCH_WAKEUP_MAKE_DIRTY) { |
| new_state |= DISPATCH_QUEUE_DIRTY; |
| } else if (new_state == old_state) { |
| os_atomic_rmw_loop_give_up(goto done); |
| } |
| }); |
| |
| if (likely((old_state ^ new_state) & enqueue)) { |
| dispatch_queue_t tq; |
| if (target == DISPATCH_QUEUE_WAKEUP_TARGET) { |
| // the rmw_loop above has no acquire barrier, as the last block |
| // of a queue asyncing to that queue is not an uncommon pattern |
| // and in that case the acquire would be completely useless |
| // |
| // so instead use depdendency ordering to read |
| // the targetq pointer. |
| os_atomic_thread_fence(dependency); |
| tq = os_atomic_load_with_dependency_on2o(dq, do_targetq, |
| (long)new_state); |
| } else { |
| tq = target; |
| } |
| dispatch_assert(_dq_state_is_enqueued(new_state)); |
| return _dispatch_queue_push_queue(tq, dq, new_state); |
| } |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| if (unlikely((old_state ^ new_state) & DISPATCH_QUEUE_MAX_QOS_MASK)) { |
| if (_dq_state_should_override(new_state)) { |
| return _dispatch_queue_class_wakeup_with_override(dq, new_state, |
| flags); |
| } |
| } |
| } else if (qos) { |
| // |
| // Someone is trying to override the last work item of the queue. |
| // |
| uint64_t old_state, new_state; |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| if (!_dq_state_drain_locked(old_state) || |
| !_dq_state_is_enqueued(old_state)) { |
| os_atomic_rmw_loop_give_up(goto done); |
| } |
| new_state = _dq_state_merge_qos(old_state, qos); |
| if (new_state == old_state) { |
| os_atomic_rmw_loop_give_up(goto done); |
| } |
| }); |
| if (_dq_state_should_override(new_state)) { |
| return _dispatch_queue_class_wakeup_with_override(dq, new_state, |
| flags); |
| } |
| #endif // HAVE_PTHREAD_WORKQUEUE_QOS |
| } |
| done: |
| if (likely(flags & DISPATCH_WAKEUP_CONSUME_2)) { |
| return _dispatch_release_2_tailcall(dq); |
| } |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_push_sync_waiter(dispatch_queue_t dq, |
| dispatch_sync_context_t dsc, dispatch_qos_t qos) |
| { |
| uint64_t old_state, new_state; |
| |
| if (unlikely(dx_type(dq) == DISPATCH_QUEUE_NETWORK_EVENT_TYPE)) { |
| DISPATCH_CLIENT_CRASH(0, |
| "dispatch_sync onto a network event queue"); |
| } |
| |
| _dispatch_trace_continuation_push(dq, dsc->_as_dc); |
| |
| if (unlikely(_dispatch_queue_push_update_tail(dq, dsc->_as_do))) { |
| // for slow waiters, we borrow the reference of the caller |
| // so we don't need to protect the wakeup with a temporary retain |
| _dispatch_queue_push_update_head(dq, dsc->_as_do); |
| if (unlikely(_dispatch_queue_is_thread_bound(dq))) { |
| return dx_wakeup(dq, qos, DISPATCH_WAKEUP_MAKE_DIRTY); |
| } |
| |
| uint64_t pending_barrier_width = |
| (dq->dq_width - 1) * DISPATCH_QUEUE_WIDTH_INTERVAL; |
| uint64_t set_owner_and_set_full_width_and_in_barrier = |
| _dispatch_lock_value_for_self() | |
| DISPATCH_QUEUE_WIDTH_FULL_BIT | DISPATCH_QUEUE_IN_BARRIER; |
| // similar to _dispatch_queue_drain_try_unlock() |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, release, { |
| new_state = _dq_state_merge_qos(old_state, qos); |
| new_state |= DISPATCH_QUEUE_DIRTY; |
| if (unlikely(_dq_state_drain_locked(old_state) || |
| !_dq_state_is_runnable(old_state))) { |
| // not runnable, so we should just handle overrides |
| } else if (_dq_state_is_base_wlh(old_state) && |
| _dq_state_is_enqueued(old_state)) { |
| // 32123779 let the event thread redrive since it's out already |
| } else if (_dq_state_has_pending_barrier(old_state) || |
| new_state + pending_barrier_width < |
| DISPATCH_QUEUE_WIDTH_FULL_BIT) { |
| // see _dispatch_queue_drain_try_lock |
| new_state &= DISPATCH_QUEUE_DRAIN_PRESERVED_BITS_MASK; |
| new_state |= set_owner_and_set_full_width_and_in_barrier; |
| } |
| }); |
| |
| if (_dq_state_is_base_wlh(old_state) && |
| (dsc->dsc_waiter == _dispatch_tid_self())) { |
| dsc->dsc_wlh_was_first = true; |
| } |
| |
| if ((old_state ^ new_state) & DISPATCH_QUEUE_IN_BARRIER) { |
| return _dispatch_queue_barrier_complete(dq, qos, 0); |
| } |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| if (unlikely((old_state ^ new_state) & DISPATCH_QUEUE_MAX_QOS_MASK)) { |
| if (_dq_state_should_override(new_state)) { |
| return _dispatch_queue_class_wakeup_with_override(dq, |
| new_state, 0); |
| } |
| } |
| } else if (unlikely(qos)) { |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, { |
| new_state = _dq_state_merge_qos(old_state, qos); |
| if (old_state == new_state) { |
| os_atomic_rmw_loop_give_up(return); |
| } |
| }); |
| if (_dq_state_should_override(new_state)) { |
| return _dispatch_queue_class_wakeup_with_override(dq, new_state, 0); |
| } |
| #endif // HAVE_PTHREAD_WORKQUEUE_QOS |
| } |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_root_queue_drain |
| |
| DISPATCH_NOINLINE |
| static bool |
| _dispatch_root_queue_drain_one_slow(dispatch_queue_t dq) |
| { |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| struct dispatch_object_s *const mediator = (void *)~0ul; |
| bool pending = false, available = true; |
| unsigned int sleep_time = DISPATCH_CONTENTION_USLEEP_START; |
| |
| do { |
| // Spin for a short while in case the contention is temporary -- e.g. |
| // when starting up after dispatch_apply, or when executing a few |
| // short continuations in a row. |
| if (_dispatch_contention_wait_until(dq->dq_items_head != mediator)) { |
| goto out; |
| } |
| // Since we have serious contention, we need to back off. |
| if (!pending) { |
| // Mark this queue as pending to avoid requests for further threads |
| (void)os_atomic_inc2o(qc, dgq_pending, relaxed); |
| pending = true; |
| } |
| _dispatch_contention_usleep(sleep_time); |
| if (fastpath(dq->dq_items_head != mediator)) goto out; |
| sleep_time *= 2; |
| } while (sleep_time < DISPATCH_CONTENTION_USLEEP_MAX); |
| |
| // The ratio of work to libdispatch overhead must be bad. This |
| // scenario implies that there are too many threads in the pool. |
| // Create a new pending thread and then exit this thread. |
| // The kernel will grant a new thread when the load subsides. |
| _dispatch_debug("contention on global queue: %p", dq); |
| available = false; |
| out: |
| if (pending) { |
| (void)os_atomic_dec2o(qc, dgq_pending, relaxed); |
| } |
| if (!available) { |
| _dispatch_global_queue_poke(dq, 1, 0); |
| } |
| return available; |
| } |
| |
| DISPATCH_ALWAYS_INLINE |
| static inline bool |
| _dispatch_root_queue_drain_one2(dispatch_queue_t dq) |
| { |
| // Wait for queue head and tail to be both non-empty or both empty |
| bool available; // <rdar://problem/15917893> |
| _dispatch_wait_until((dq->dq_items_head != NULL) == |
| (available = (dq->dq_items_tail != NULL))); |
| return available; |
| } |
| |
| DISPATCH_ALWAYS_INLINE_NDEBUG |
| static inline struct dispatch_object_s * |
| _dispatch_root_queue_drain_one(dispatch_queue_t dq) |
| { |
| struct dispatch_object_s *head, *next, *const mediator = (void *)~0ul; |
| |
| start: |
| // The mediator value acts both as a "lock" and a signal |
| head = os_atomic_xchg2o(dq, dq_items_head, mediator, relaxed); |
| |
| if (slowpath(head == NULL)) { |
| // The first xchg on the tail will tell the enqueueing thread that it |
| // is safe to blindly write out to the head pointer. A cmpxchg honors |
| // the algorithm. |
| if (slowpath(!os_atomic_cmpxchg2o(dq, dq_items_head, mediator, |
| NULL, relaxed))) { |
| goto start; |
| } |
| if (slowpath(dq->dq_items_tail) && // <rdar://problem/14416349> |
| _dispatch_root_queue_drain_one2(dq)) { |
| goto start; |
| } |
| _dispatch_root_queue_debug("no work on global queue: %p", dq); |
| return NULL; |
| } |
| |
| if (slowpath(head == mediator)) { |
| // This thread lost the race for ownership of the queue. |
| if (fastpath(_dispatch_root_queue_drain_one_slow(dq))) { |
| goto start; |
| } |
| return NULL; |
| } |
| |
| // Restore the head pointer to a sane value before returning. |
| // If 'next' is NULL, then this item _might_ be the last item. |
| next = fastpath(head->do_next); |
| |
| if (slowpath(!next)) { |
| os_atomic_store2o(dq, dq_items_head, NULL, relaxed); |
| // 22708742: set tail to NULL with release, so that NULL write to head |
| // above doesn't clobber head from concurrent enqueuer |
| if (os_atomic_cmpxchg2o(dq, dq_items_tail, head, NULL, release)) { |
| // both head and tail are NULL now |
| goto out; |
| } |
| // There must be a next item now. |
| next = os_mpsc_get_next(head, do_next); |
| } |
| |
| os_atomic_store2o(dq, dq_items_head, next, relaxed); |
| _dispatch_global_queue_poke(dq, 1, 0); |
| out: |
| return head; |
| } |
| |
| #if DISPATCH_USE_KEVENT_WORKQUEUE |
| void |
| _dispatch_root_queue_drain_deferred_wlh(dispatch_deferred_items_t ddi |
| DISPATCH_PERF_MON_ARGS_PROTO) |
| { |
| dispatch_queue_t rq = ddi->ddi_stashed_rq; |
| dispatch_queue_t dq = ddi->ddi_stashed_dou._dq; |
| _dispatch_queue_set_current(rq); |
| dispatch_priority_t old_pri = _dispatch_set_basepri_wlh(rq->dq_priority); |
| dispatch_invoke_context_s dic = { }; |
| dispatch_invoke_flags_t flags = DISPATCH_INVOKE_WORKER_DRAIN | |
| DISPATCH_INVOKE_REDIRECTING_DRAIN | DISPATCH_INVOKE_WLH; |
| _dispatch_queue_drain_init_narrowing_check_deadline(&dic, rq->dq_priority); |
| uint64_t dq_state; |
| |
| ddi->ddi_wlh_servicing = true; |
| if (unlikely(_dispatch_needs_to_return_to_kernel())) { |
| _dispatch_return_to_kernel(); |
| } |
| retry: |
| dispatch_assert(ddi->ddi_wlh_needs_delete); |
| _dispatch_trace_continuation_pop(rq, dq); |
| |
| if (_dispatch_queue_drain_try_lock_wlh(dq, &dq_state)) { |
| dx_invoke(dq, &dic, flags); |
| if (!ddi->ddi_wlh_needs_delete) { |
| goto park; |
| } |
| dq_state = os_atomic_load2o(dq, dq_state, relaxed); |
| if (unlikely(!_dq_state_is_base_wlh(dq_state))) { // rdar://32671286 |
| goto park; |
| } |
| if (unlikely(_dq_state_is_enqueued_on_target(dq_state))) { |
| _dispatch_retain(dq); |
| _dispatch_trace_continuation_push(dq->do_targetq, dq); |
| goto retry; |
| } |
| } else { |
| _dispatch_release_no_dispose(dq); |
| } |
| |
| _dispatch_event_loop_leave_deferred((dispatch_wlh_t)dq, dq_state); |
| |
| park: |
| // event thread that could steal |
| _dispatch_perfmon_end(perfmon_thread_event_steal); |
| _dispatch_reset_basepri(old_pri); |
| _dispatch_reset_basepri_override(); |
| _dispatch_queue_set_current(NULL); |
| |
| _dispatch_voucher_debug("root queue clear", NULL); |
| _dispatch_reset_voucher(NULL, DISPATCH_THREAD_PARK); |
| } |
| |
| void |
| _dispatch_root_queue_drain_deferred_item(dispatch_deferred_items_t ddi |
| DISPATCH_PERF_MON_ARGS_PROTO) |
| { |
| dispatch_queue_t rq = ddi->ddi_stashed_rq; |
| _dispatch_queue_set_current(rq); |
| dispatch_priority_t old_pri = _dispatch_set_basepri(rq->dq_priority); |
| |
| dispatch_invoke_context_s dic = { }; |
| dispatch_invoke_flags_t flags = DISPATCH_INVOKE_WORKER_DRAIN | |
| DISPATCH_INVOKE_REDIRECTING_DRAIN; |
| #if DISPATCH_COCOA_COMPAT |
| _dispatch_last_resort_autorelease_pool_push(&dic); |
| #endif // DISPATCH_COCOA_COMPAT |
| _dispatch_queue_drain_init_narrowing_check_deadline(&dic, rq->dq_priority); |
| _dispatch_continuation_pop_inline(ddi->ddi_stashed_dou, &dic, flags, rq); |
| |
| // event thread that could steal |
| _dispatch_perfmon_end(perfmon_thread_event_steal); |
| #if DISPATCH_COCOA_COMPAT |
| _dispatch_last_resort_autorelease_pool_pop(&dic); |
| #endif // DISPATCH_COCOA_COMPAT |
| _dispatch_reset_basepri(old_pri); |
| _dispatch_reset_basepri_override(); |
| _dispatch_queue_set_current(NULL); |
| |
| _dispatch_voucher_debug("root queue clear", NULL); |
| _dispatch_reset_voucher(NULL, DISPATCH_THREAD_PARK); |
| } |
| #endif |
| |
| DISPATCH_NOT_TAIL_CALLED // prevent tailcall (for Instrument DTrace probe) |
| static void |
| _dispatch_root_queue_drain(dispatch_queue_t dq, pthread_priority_t pp) |
| { |
| #if DISPATCH_DEBUG |
| dispatch_queue_t cq; |
| if (slowpath(cq = _dispatch_queue_get_current())) { |
| DISPATCH_INTERNAL_CRASH(cq, "Premature thread recycling"); |
| } |
| #endif |
| _dispatch_queue_set_current(dq); |
| dispatch_priority_t pri = dq->dq_priority; |
| if (!pri) pri = _dispatch_priority_from_pp(pp); |
| dispatch_priority_t old_dbp = _dispatch_set_basepri(pri); |
| _dispatch_adopt_wlh_anon(); |
| |
| struct dispatch_object_s *item; |
| bool reset = false; |
| dispatch_invoke_context_s dic = { }; |
| #if DISPATCH_COCOA_COMPAT |
| _dispatch_last_resort_autorelease_pool_push(&dic); |
| #endif // DISPATCH_COCOA_COMPAT |
| dispatch_invoke_flags_t flags = DISPATCH_INVOKE_WORKER_DRAIN | |
| DISPATCH_INVOKE_REDIRECTING_DRAIN; |
| _dispatch_queue_drain_init_narrowing_check_deadline(&dic, pri); |
| _dispatch_perfmon_start(); |
| while ((item = fastpath(_dispatch_root_queue_drain_one(dq)))) { |
| if (reset) _dispatch_wqthread_override_reset(); |
| _dispatch_continuation_pop_inline(item, &dic, flags, dq); |
| reset = _dispatch_reset_basepri_override(); |
| if (unlikely(_dispatch_queue_drain_should_narrow(&dic))) { |
| break; |
| } |
| } |
| |
| // overcommit or not. worker thread |
| if (pri & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG) { |
| _dispatch_perfmon_end(perfmon_thread_worker_oc); |
| } else { |
| _dispatch_perfmon_end(perfmon_thread_worker_non_oc); |
| } |
| |
| #if DISPATCH_COCOA_COMPAT |
| _dispatch_last_resort_autorelease_pool_pop(&dic); |
| #endif // DISPATCH_COCOA_COMPAT |
| _dispatch_reset_wlh(); |
| _dispatch_reset_basepri(old_dbp); |
| _dispatch_reset_basepri_override(); |
| _dispatch_queue_set_current(NULL); |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_worker_thread |
| |
| #if HAVE_PTHREAD_WORKQUEUES |
| static void |
| _dispatch_worker_thread4(void *context) |
| { |
| dispatch_queue_t dq = context; |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| |
| _dispatch_introspection_thread_add(); |
| int pending = os_atomic_dec2o(qc, dgq_pending, relaxed); |
| dispatch_assert(pending >= 0); |
| _dispatch_root_queue_drain(dq, _dispatch_get_priority()); |
| _dispatch_voucher_debug("root queue clear", NULL); |
| _dispatch_reset_voucher(NULL, DISPATCH_THREAD_PARK); |
| } |
| |
| #if HAVE_PTHREAD_WORKQUEUE_QOS |
| static void |
| _dispatch_worker_thread3(pthread_priority_t pp) |
| { |
| bool overcommit = pp & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG; |
| dispatch_queue_t dq; |
| pp &= _PTHREAD_PRIORITY_OVERCOMMIT_FLAG | ~_PTHREAD_PRIORITY_FLAGS_MASK; |
| _dispatch_thread_setspecific(dispatch_priority_key, (void *)(uintptr_t)pp); |
| dq = _dispatch_get_root_queue(_dispatch_qos_from_pp(pp), overcommit); |
| return _dispatch_worker_thread4(dq); |
| } |
| #endif // HAVE_PTHREAD_WORKQUEUE_QOS |
| |
| #if DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| static void |
| _dispatch_worker_thread2(int priority, int options, |
| void *context DISPATCH_UNUSED) |
| { |
| dispatch_assert(priority >= 0 && priority < WORKQ_NUM_PRIOQUEUE); |
| dispatch_assert(!(options & ~WORKQ_ADDTHREADS_OPTION_OVERCOMMIT)); |
| dispatch_queue_t dq = _dispatch_wq2root_queues[priority][options]; |
| |
| return _dispatch_worker_thread4(dq); |
| } |
| #endif // DISPATCH_USE_PTHREAD_WORKQUEUE_SETDISPATCH_NP |
| #endif // HAVE_PTHREAD_WORKQUEUES |
| |
| #if DISPATCH_USE_PTHREAD_POOL |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| #if defined(_WIN32) |
| static unsigned WINAPI |
| _dispatch_worker_thread_thunk(LPVOID lpParameter) |
| { |
| _dispatch_worker_thread(lpParameter); |
| return 0; |
| } |
| #endif |
| |
| static void * |
| _dispatch_worker_thread(void *context) |
| { |
| dispatch_queue_t dq = context; |
| dispatch_root_queue_context_t qc = dq->do_ctxt; |
| dispatch_pthread_root_queue_context_t pqc = qc->dgq_ctxt; |
| |
| int pending = os_atomic_dec2o(qc, dgq_pending, relaxed); |
| if (unlikely(pending < 0)) { |
| DISPATCH_INTERNAL_CRASH(pending, "Pending thread request underflow"); |
| } |
| |
| if (pqc->dpq_observer_hooks.queue_will_execute) { |
| _dispatch_set_pthread_root_queue_observer_hooks( |
| &pqc->dpq_observer_hooks); |
| } |
| if (pqc->dpq_thread_configure) { |
| pqc->dpq_thread_configure(); |
| } |
| |
| // workaround tweaks the kernel workqueue does for us |
| #if !defined(_WIN32) |
| _dispatch_sigmask(); |
| #endif |
| _dispatch_introspection_thread_add(); |
| |
| #if DISPATCH_USE_INTERNAL_WORKQUEUE |
| bool overcommit = (qc->dgq_wq_options & WORKQ_ADDTHREADS_OPTION_OVERCOMMIT); |
| bool manager = (dq == &_dispatch_mgr_root_queue); |
| bool monitored = !(overcommit || manager); |
| if (monitored) { |
| _dispatch_workq_worker_register(dq, qc->dgq_qos); |
| } |
| #endif |
| |
| const int64_t timeout = 5ull * NSEC_PER_SEC; |
| pthread_priority_t old_pri = _dispatch_get_priority(); |
| do { |
| _dispatch_root_queue_drain(dq, old_pri); |
| _dispatch_reset_priority_and_voucher(old_pri, NULL); |
| } while (dispatch_semaphore_wait(&pqc->dpq_thread_mediator, |
| dispatch_time(0, timeout)) == 0); |
| |
| #if DISPATCH_USE_INTERNAL_WORKQUEUE |
| if (monitored) { |
| _dispatch_workq_worker_unregister(dq, qc->dgq_qos); |
| } |
| #endif |
| (void)os_atomic_inc2o(qc, dgq_thread_pool_size, release); |
| _dispatch_global_queue_poke(dq, 1, 0); |
| _dispatch_release(dq); // retained in _dispatch_global_queue_poke_slow |
| return NULL; |
| } |
| #endif // DISPATCH_USE_PTHREAD_POOL |
| |
| #pragma mark - |
| #pragma mark dispatch_network_root_queue |
| #if TARGET_OS_MAC |
| |
| dispatch_queue_t |
| _dispatch_network_root_queue_create_4NW(const char *label, |
| const pthread_attr_t *attrs, dispatch_block_t configure) |
| { |
| unsigned long flags = dispatch_pthread_root_queue_flags_pool_size(1); |
| return dispatch_pthread_root_queue_create(label, flags, attrs, configure); |
| } |
| |
| #endif // TARGET_OS_MAC |
| #pragma mark - |
| #pragma mark dispatch_runloop_queue |
| |
| static bool _dispatch_program_is_probably_callback_driven; |
| |
| #if DISPATCH_COCOA_COMPAT |
| |
| dispatch_queue_t |
| _dispatch_runloop_root_queue_create_4CF(const char *label, unsigned long flags) |
| { |
| dispatch_queue_t dq; |
| size_t dqs; |
| |
| if (slowpath(flags)) { |
| return DISPATCH_BAD_INPUT; |
| } |
| dqs = sizeof(struct dispatch_queue_s) - DISPATCH_QUEUE_CACHELINE_PAD; |
| dq = _dispatch_object_alloc(DISPATCH_VTABLE(queue_runloop), dqs); |
| _dispatch_queue_init(dq, DQF_THREAD_BOUND | DQF_CANNOT_TRYSYNC, 1, |
| DISPATCH_QUEUE_ROLE_BASE_ANON); |
| dq->do_targetq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, true); |
| dq->dq_label = label ? label : "runloop-queue"; // no-copy contract |
| _dispatch_runloop_queue_handle_init(dq); |
| _dispatch_queue_set_bound_thread(dq); |
| _dispatch_object_debug(dq, "%s", __func__); |
| return _dispatch_introspection_queue_create(dq); |
| } |
| |
| void |
| _dispatch_runloop_queue_xref_dispose(dispatch_queue_t dq) |
| { |
| _dispatch_object_debug(dq, "%s", __func__); |
| |
| dispatch_qos_t qos = _dispatch_runloop_queue_reset_max_qos(dq); |
| _dispatch_queue_clear_bound_thread(dq); |
| dx_wakeup(dq, qos, DISPATCH_WAKEUP_MAKE_DIRTY); |
| if (qos) _dispatch_thread_override_end(DISPATCH_QUEUE_DRAIN_OWNER(dq), dq); |
| } |
| |
| void |
| _dispatch_runloop_queue_dispose(dispatch_queue_t dq, bool *allow_free) |
| { |
| _dispatch_object_debug(dq, "%s", __func__); |
| _dispatch_introspection_queue_dispose(dq); |
| _dispatch_runloop_queue_handle_dispose(dq); |
| _dispatch_queue_destroy(dq, allow_free); |
| } |
| |
| bool |
| _dispatch_runloop_root_queue_perform_4CF(dispatch_queue_t dq) |
| { |
| if (slowpath(dq->do_vtable != DISPATCH_VTABLE(queue_runloop))) { |
| DISPATCH_CLIENT_CRASH(dq->do_vtable, "Not a runloop queue"); |
| } |
| dispatch_retain(dq); |
| bool r = _dispatch_runloop_queue_drain_one(dq); |
| dispatch_release(dq); |
| return r; |
| } |
| |
| void |
| _dispatch_runloop_root_queue_wakeup_4CF(dispatch_queue_t dq) |
| { |
| if (slowpath(dq->do_vtable != DISPATCH_VTABLE(queue_runloop))) { |
| DISPATCH_CLIENT_CRASH(dq->do_vtable, "Not a runloop queue"); |
| } |
| _dispatch_runloop_queue_wakeup(dq, 0, false); |
| } |
| |
| #if TARGET_OS_MAC |
| dispatch_runloop_handle_t |
| _dispatch_runloop_root_queue_get_port_4CF(dispatch_queue_t dq) |
| { |
| if (slowpath(dq->do_vtable != DISPATCH_VTABLE(queue_runloop))) { |
| DISPATCH_CLIENT_CRASH(dq->do_vtable, "Not a runloop queue"); |
| } |
| return _dispatch_runloop_queue_get_handle(dq); |
| } |
| #endif |
| |
| static void |
| _dispatch_runloop_queue_handle_init(void *ctxt) |
| { |
| dispatch_queue_t dq = (dispatch_queue_t)ctxt; |
| dispatch_runloop_handle_t handle; |
| |
| _dispatch_fork_becomes_unsafe(); |
| |
| #if TARGET_OS_MAC |
| mach_port_t mp; |
| kern_return_t kr; |
| kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &mp); |
| DISPATCH_VERIFY_MIG(kr); |
| (void)dispatch_assume_zero(kr); |
| kr = mach_port_insert_right(mach_task_self(), mp, mp, |
| MACH_MSG_TYPE_MAKE_SEND); |
| DISPATCH_VERIFY_MIG(kr); |
| (void)dispatch_assume_zero(kr); |
| if (dq != &_dispatch_main_q) { |
| struct mach_port_limits limits = { |
| .mpl_qlimit = 1, |
| }; |
| kr = mach_port_set_attributes(mach_task_self(), mp, |
| MACH_PORT_LIMITS_INFO, (mach_port_info_t)&limits, |
| sizeof(limits)); |
| DISPATCH_VERIFY_MIG(kr); |
| (void)dispatch_assume_zero(kr); |
| } |
| handle = mp; |
| #elif defined(__linux__) |
| int fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK); |
| if (fd == -1) { |
| int err = errno; |
| switch (err) { |
| case EMFILE: |
| DISPATCH_CLIENT_CRASH(err, "eventfd() failure: " |
| "process is out of file descriptors"); |
| break; |
| case ENFILE: |
| DISPATCH_CLIENT_CRASH(err, "eventfd() failure: " |
| "system is out of file descriptors"); |
| break; |
| case ENOMEM: |
| DISPATCH_CLIENT_CRASH(err, "eventfd() failure: " |
| "kernel is out of memory"); |
| break; |
| default: |
| DISPATCH_INTERNAL_CRASH(err, "eventfd() failure"); |
| break; |
| } |
| } |
| handle = fd; |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| _dispatch_runloop_queue_set_handle(dq, handle); |
| |
| _dispatch_program_is_probably_callback_driven = true; |
| } |
| |
| static void |
| _dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq) |
| { |
| dispatch_runloop_handle_t handle = _dispatch_runloop_queue_get_handle(dq); |
| if (!_dispatch_runloop_handle_is_valid(handle)) { |
| return; |
| } |
| dq->do_ctxt = NULL; |
| #if TARGET_OS_MAC |
| mach_port_t mp = handle; |
| kern_return_t kr = mach_port_deallocate(mach_task_self(), mp); |
| DISPATCH_VERIFY_MIG(kr); |
| (void)dispatch_assume_zero(kr); |
| kr = mach_port_mod_refs(mach_task_self(), mp, MACH_PORT_RIGHT_RECEIVE, -1); |
| DISPATCH_VERIFY_MIG(kr); |
| (void)dispatch_assume_zero(kr); |
| #elif defined(__linux__) |
| int rc = close(handle); |
| (void)dispatch_assume_zero(rc); |
| #else |
| #error "runloop support not implemented on this platform" |
| #endif |
| } |
| |
| #pragma mark - |
| #pragma mark dispatch_main_queue |
| |
| dispatch_runloop_handle_t |
| _dispatch_get_main_queue_handle_4CF(void) |
| { |
| dispatch_queue_t dq = &_dispatch_main_q; |
| dispatch_once_f(&_dispatch_main_q_handle_pred, dq, |
| _dispatch_runloop_queue_handle_init); |
| return _dispatch_runloop_queue_get_handle(dq); |
| } |
| |
| #if TARGET_OS_MAC |
| dispatch_runloop_handle_t |
| _dispatch_get_main_queue_port_4CF(void) |
| { |
| return _dispatch_get_main_queue_handle_4CF(); |
| } |
| #endif |
| |
| static bool main_q_is_draining; |
| |
| // 6618342 Contact the team that owns the Instrument DTrace probe before |
| // renaming this symbol |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_set_mainq_drain_state(bool arg) |
| { |
| main_q_is_draining = arg; |
| } |
| |
| void |
| _dispatch_main_queue_callback_4CF( |
| void *ignored DISPATCH_UNUSED) |
| { |
| if (main_q_is_draining) { |
| return; |
| } |
| _dispatch_queue_set_mainq_drain_state(true); |
| _dispatch_main_queue_drain(); |
| _dispatch_queue_set_mainq_drain_state(false); |
| } |
| |
| #endif |
| |
| void |
| dispatch_main(void) |
| { |
| _dispatch_root_queues_init(); |
| #if HAVE_PTHREAD_MAIN_NP |
| if (pthread_main_np()) { |
| #endif |
| _dispatch_object_debug(&_dispatch_main_q, "%s", __func__); |
| _dispatch_program_is_probably_callback_driven = true; |
| _dispatch_ktrace0(ARIADNE_ENTER_DISPATCH_MAIN_CODE); |
| #ifdef __linux__ |
| // On Linux, if the main thread calls pthread_exit, the process becomes a zombie. |
| // To avoid that, just before calling pthread_exit we register a TSD destructor |
| // that will call _dispatch_sig_thread -- thus capturing the main thread in sigsuspend. |
| // This relies on an implementation detail (currently true in glibc) that TSD destructors |
| // will be called in the order of creation to cause all the TSD cleanup functions to |
| // run before the thread becomes trapped in sigsuspend. |
| pthread_key_t dispatch_main_key; |
| pthread_key_create(&dispatch_main_key, _dispatch_sig_thread); |
| pthread_setspecific(dispatch_main_key, &dispatch_main_key); |
| _dispatch_sigmask(); |
| #endif |
| #if defined(_WIN32) |
| _endthreadex(0); |
| #else |
| pthread_exit(NULL); |
| #endif |
| DISPATCH_INTERNAL_CRASH(errno, "pthread_exit() returned"); |
| #if HAVE_PTHREAD_MAIN_NP |
| } |
| DISPATCH_CLIENT_CRASH(0, "dispatch_main() must be called on the main thread"); |
| #endif |
| } |
| |
| #if !defined(_WIN32) |
| DISPATCH_NOINLINE DISPATCH_NORETURN |
| static void |
| _dispatch_sigsuspend(void) |
| { |
| static const sigset_t mask; |
| |
| for (;;) { |
| sigsuspend(&mask); |
| } |
| } |
| #endif |
| |
| DISPATCH_NORETURN |
| static void |
| _dispatch_sig_thread(void *ctxt DISPATCH_UNUSED) |
| { |
| // never returns, so burn bridges behind us |
| _dispatch_clear_stack(0); |
| #if !defined(_WIN32) |
| _dispatch_sigsuspend(); |
| #endif |
| } |
| |
| DISPATCH_NOINLINE |
| static void |
| _dispatch_queue_cleanup2(void) |
| { |
| dispatch_queue_t dq = &_dispatch_main_q; |
| uint64_t old_state, new_state; |
| |
| // Turning the main queue from a runloop queue into an ordinary serial queue |
| // is a 3 steps operation: |
| // 1. finish taking the main queue lock the usual way |
| // 2. clear the THREAD_BOUND flag |
| // 3. do a handoff |
| // |
| // If an enqueuer executes concurrently, he may do the wakeup the runloop |
| // way, because he still believes the queue to be thread-bound, but the |
| // dirty bit will force this codepath to notice the enqueue, and the usual |
| // lock transfer will do the proper wakeup. |
| os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, acquire, { |
| new_state = old_state & ~DISPATCH_QUEUE_DIRTY; |
| new_state += DISPATCH_QUEUE_WIDTH_INTERVAL; |
| new_state += DISPATCH_QUEUE_IN_BARRIER; |
| }); |
| _dispatch_queue_atomic_flags_clear(dq, DQF_THREAD_BOUND|DQF_CANNOT_TRYSYNC); |
| _dispatch_queue_barrier_complete(dq, 0, 0); |
| |
| // overload the "probably" variable to mean that dispatch_main() or |
| // similar non-POSIX API was called |
| // this has to run before the DISPATCH_COCOA_COMPAT below |
| // See dispatch_main for call to _dispatch_sig_thread on linux. |
| #ifndef __linux__ |
| if (_dispatch_program_is_probably_callback_driven) { |
| _dispatch_barrier_async_detached_f(_dispatch_get_root_queue( |
| DISPATCH_QOS_DEFAULT, true), NULL, _dispatch_sig_thread); |
| sleep(1); // workaround 6778970 |
| } |
| #endif |
| |
| #if DISPATCH_COCOA_COMPAT |
| dispatch_once_f(&_dispatch_main_q_handle_pred, dq, |
| _dispatch_runloop_queue_handle_init); |
| _dispatch_runloop_queue_handle_dispose(dq); |
| #endif |
| } |
| |
| static void DISPATCH_TSD_DTOR_CC |
| _dispatch_queue_cleanup(void *ctxt) |
| { |
| if (ctxt == &_dispatch_main_q) { |
| return _dispatch_queue_cleanup2(); |
| } |
| // POSIX defines that destructors are only called if 'ctxt' is non-null |
| DISPATCH_INTERNAL_CRASH(ctxt, |
| "Premature thread exit while a dispatch queue is running"); |
| } |
| |
| static void DISPATCH_TSD_DTOR_CC |
| _dispatch_wlh_cleanup(void *ctxt) |
| { |
| // POSIX defines that destructors are only called if 'ctxt' is non-null |
| dispatch_queue_t wlh; |
| wlh = (dispatch_queue_t)((uintptr_t)ctxt & ~DISPATCH_WLH_STORAGE_REF); |
| _dispatch_queue_release_storage(wlh); |
| } |
| |
| DISPATCH_NORETURN |
| static void DISPATCH_TSD_DTOR_CC |
| _dispatch_deferred_items_cleanup(void *ctxt) |
| { |
| // POSIX defines that destructors are only called if 'ctxt' is non-null |
| DISPATCH_INTERNAL_CRASH(ctxt, |
| "Premature thread exit with unhandled deferred items"); |
| } |
| |
| DISPATCH_NORETURN |
| static DISPATCH_TSD_DTOR_CC void |
| _dispatch_frame_cleanup(void *ctxt) |
| { |
| // POSIX defines that destructors are only called if 'ctxt' is non-null |
| DISPATCH_INTERNAL_CRASH(ctxt, |
| "Premature thread exit while a dispatch frame is active"); |
| } |
| |
| DISPATCH_NORETURN |
| static void DISPATCH_TSD_DTOR_CC |
| _dispatch_context_cleanup(void *ctxt) |
| { |
| // POSIX defines that destructors are only called if 'ctxt' is non-null |
| DISPATCH_INTERNAL_CRASH(ctxt, |
| "Premature thread exit while a dispatch context is set"); |
| } |