| /* GLIB - Library of useful routines for C programming |
| * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald |
| * |
| * GThreadPool: thread pool implementation. |
| * Copyright (C) 2000 Sebastian Wilhelmi; University of Karlsruhe |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| /* |
| * MT safe |
| */ |
| |
| #include "config.h" |
| |
| #include "gthreadpool.h" |
| |
| #include "gasyncqueue.h" |
| #include "gasyncqueueprivate.h" |
| #include "gmain.h" |
| #include "gtestutils.h" |
| #include "gtimer.h" |
| |
| /** |
| * SECTION:thread_pools |
| * @title: Thread Pools |
| * @short_description: pools of threads to execute work concurrently |
| * @see_also: #GThread |
| * |
| * Sometimes you wish to asynchronously fork out the execution of work |
| * and continue working in your own thread. If that will happen often, |
| * the overhead of starting and destroying a thread each time might be |
| * too high. In such cases reusing already started threads seems like a |
| * good idea. And it indeed is, but implementing this can be tedious |
| * and error-prone. |
| * |
| * Therefore GLib provides thread pools for your convenience. An added |
| * advantage is, that the threads can be shared between the different |
| * subsystems of your program, when they are using GLib. |
| * |
| * To create a new thread pool, you use g_thread_pool_new(). |
| * It is destroyed by g_thread_pool_free(). |
| * |
| * If you want to execute a certain task within a thread pool, |
| * you call g_thread_pool_push(). |
| * |
| * To get the current number of running threads you call |
| * g_thread_pool_get_num_threads(). To get the number of still |
| * unprocessed tasks you call g_thread_pool_unprocessed(). To control |
| * the maximal number of threads for a thread pool, you use |
| * g_thread_pool_get_max_threads() and g_thread_pool_set_max_threads(). |
| * |
| * Finally you can control the number of unused threads, that are kept |
| * alive by GLib for future use. The current number can be fetched with |
| * g_thread_pool_get_num_unused_threads(). The maximal number can be |
| * controlled by g_thread_pool_get_max_unused_threads() and |
| * g_thread_pool_set_max_unused_threads(). All currently unused threads |
| * can be stopped by calling g_thread_pool_stop_unused_threads(). |
| */ |
| |
| #define DEBUG_MSG(x) |
| /* #define DEBUG_MSG(args) g_printerr args ; g_printerr ("\n"); */ |
| |
| typedef struct _GRealThreadPool GRealThreadPool; |
| |
| /** |
| * GThreadPool: |
| * @func: the function to execute in the threads of this pool |
| * @user_data: the user data for the threads of this pool |
| * @exclusive: are all threads exclusive to this pool |
| * |
| * The #GThreadPool struct represents a thread pool. It has three |
| * public read-only members, but the underlying struct is bigger, |
| * so you must not copy this struct. |
| */ |
| struct _GRealThreadPool |
| { |
| GThreadPool pool; |
| GAsyncQueue *queue; |
| GCond cond; |
| gint max_threads; |
| gint num_threads; |
| gboolean running; |
| gboolean immediate; |
| gboolean waiting; |
| GCompareDataFunc sort_func; |
| gpointer sort_user_data; |
| }; |
| |
| /* The following is just an address to mark the wakeup order for a |
| * thread, it could be any address (as long, as it isn't a valid |
| * GThreadPool address) |
| */ |
| static const gpointer wakeup_thread_marker = (gpointer) &g_thread_pool_new; |
| static gint wakeup_thread_serial = 0; |
| |
| /* Here all unused threads are waiting */ |
| static GAsyncQueue *unused_thread_queue = NULL; |
| static gint unused_threads = 0; |
| static gint max_unused_threads = 2; |
| static gint kill_unused_threads = 0; |
| static guint max_idle_time = 15 * 1000; |
| |
| static void g_thread_pool_queue_push_unlocked (GRealThreadPool *pool, |
| gpointer data); |
| static void g_thread_pool_free_internal (GRealThreadPool *pool); |
| static gpointer g_thread_pool_thread_proxy (gpointer data); |
| static gboolean g_thread_pool_start_thread (GRealThreadPool *pool, |
| GError **error); |
| static void g_thread_pool_wakeup_and_stop_all (GRealThreadPool *pool); |
| static GRealThreadPool* g_thread_pool_wait_for_new_pool (void); |
| static gpointer g_thread_pool_wait_for_new_task (GRealThreadPool *pool); |
| |
| static void |
| g_thread_pool_queue_push_unlocked (GRealThreadPool *pool, |
| gpointer data) |
| { |
| if (pool->sort_func) |
| g_async_queue_push_sorted_unlocked (pool->queue, |
| data, |
| pool->sort_func, |
| pool->sort_user_data); |
| else |
| g_async_queue_push_unlocked (pool->queue, data); |
| } |
| |
| static GRealThreadPool* |
| g_thread_pool_wait_for_new_pool (void) |
| { |
| GRealThreadPool *pool; |
| gint local_wakeup_thread_serial; |
| guint local_max_unused_threads; |
| gint local_max_idle_time; |
| gint last_wakeup_thread_serial; |
| gboolean have_relayed_thread_marker = FALSE; |
| |
| local_max_unused_threads = g_atomic_int_get (&max_unused_threads); |
| local_max_idle_time = g_atomic_int_get (&max_idle_time); |
| last_wakeup_thread_serial = g_atomic_int_get (&wakeup_thread_serial); |
| |
| g_atomic_int_inc (&unused_threads); |
| |
| do |
| { |
| if (g_atomic_int_get (&unused_threads) >= local_max_unused_threads) |
| { |
| /* If this is a superfluous thread, stop it. */ |
| pool = NULL; |
| } |
| else if (local_max_idle_time > 0) |
| { |
| /* If a maximal idle time is given, wait for the given time. */ |
| DEBUG_MSG (("thread %p waiting in global pool for %f seconds.", |
| g_thread_self (), local_max_idle_time / 1000.0)); |
| |
| pool = g_async_queue_timeout_pop (unused_thread_queue, |
| local_max_idle_time * 1000); |
| } |
| else |
| { |
| /* If no maximal idle time is given, wait indefinitely. */ |
| DEBUG_MSG (("thread %p waiting in global pool.", g_thread_self ())); |
| pool = g_async_queue_pop (unused_thread_queue); |
| } |
| |
| if (pool == wakeup_thread_marker) |
| { |
| local_wakeup_thread_serial = g_atomic_int_get (&wakeup_thread_serial); |
| if (last_wakeup_thread_serial == local_wakeup_thread_serial) |
| { |
| if (!have_relayed_thread_marker) |
| { |
| /* If this wakeup marker has been received for |
| * the second time, relay it. |
| */ |
| DEBUG_MSG (("thread %p relaying wakeup message to " |
| "waiting thread with lower serial.", |
| g_thread_self ())); |
| |
| g_async_queue_push (unused_thread_queue, wakeup_thread_marker); |
| have_relayed_thread_marker = TRUE; |
| |
| /* If a wakeup marker has been relayed, this thread |
| * will get out of the way for 100 microseconds to |
| * avoid receiving this marker again. |
| */ |
| g_usleep (100); |
| } |
| } |
| else |
| { |
| if (g_atomic_int_add (&kill_unused_threads, -1) > 0) |
| { |
| pool = NULL; |
| break; |
| } |
| |
| DEBUG_MSG (("thread %p updating to new limits.", |
| g_thread_self ())); |
| |
| local_max_unused_threads = g_atomic_int_get (&max_unused_threads); |
| local_max_idle_time = g_atomic_int_get (&max_idle_time); |
| last_wakeup_thread_serial = local_wakeup_thread_serial; |
| |
| have_relayed_thread_marker = FALSE; |
| } |
| } |
| } |
| while (pool == wakeup_thread_marker); |
| |
| g_atomic_int_add (&unused_threads, -1); |
| |
| return pool; |
| } |
| |
| static gpointer |
| g_thread_pool_wait_for_new_task (GRealThreadPool *pool) |
| { |
| gpointer task = NULL; |
| |
| if (pool->running || (!pool->immediate && |
| g_async_queue_length_unlocked (pool->queue) > 0)) |
| { |
| /* This thread pool is still active. */ |
| if (pool->num_threads > pool->max_threads && pool->max_threads != -1) |
| { |
| /* This is a superfluous thread, so it goes to the global pool. */ |
| DEBUG_MSG (("superfluous thread %p in pool %p.", |
| g_thread_self (), pool)); |
| } |
| else if (pool->pool.exclusive) |
| { |
| /* Exclusive threads stay attached to the pool. */ |
| task = g_async_queue_pop_unlocked (pool->queue); |
| |
| DEBUG_MSG (("thread %p in exclusive pool %p waits for task " |
| "(%d running, %d unprocessed).", |
| g_thread_self (), pool, pool->num_threads, |
| g_async_queue_length_unlocked (pool->queue))); |
| } |
| else |
| { |
| /* A thread will wait for new tasks for at most 1/2 |
| * second before going to the global pool. |
| */ |
| DEBUG_MSG (("thread %p in pool %p waits for up to a 1/2 second for task " |
| "(%d running, %d unprocessed).", |
| g_thread_self (), pool, pool->num_threads, |
| g_async_queue_length_unlocked (pool->queue))); |
| |
| task = g_async_queue_timeout_pop_unlocked (pool->queue, |
| G_USEC_PER_SEC / 2); |
| } |
| } |
| else |
| { |
| /* This thread pool is inactive, it will no longer process tasks. */ |
| DEBUG_MSG (("pool %p not active, thread %p will go to global pool " |
| "(running: %s, immediate: %s, len: %d).", |
| pool, g_thread_self (), |
| pool->running ? "true" : "false", |
| pool->immediate ? "true" : "false", |
| g_async_queue_length_unlocked (pool->queue))); |
| } |
| |
| return task; |
| } |
| |
| |
| static gpointer |
| g_thread_pool_thread_proxy (gpointer data) |
| { |
| GRealThreadPool *pool; |
| |
| pool = data; |
| |
| DEBUG_MSG (("thread %p started for pool %p.", g_thread_self (), pool)); |
| |
| g_async_queue_lock (pool->queue); |
| |
| while (TRUE) |
| { |
| gpointer task; |
| |
| task = g_thread_pool_wait_for_new_task (pool); |
| if (task) |
| { |
| if (pool->running || !pool->immediate) |
| { |
| /* A task was received and the thread pool is active, |
| * so execute the function. |
| */ |
| g_async_queue_unlock (pool->queue); |
| DEBUG_MSG (("thread %p in pool %p calling func.", |
| g_thread_self (), pool)); |
| pool->pool.func (task, pool->pool.user_data); |
| g_async_queue_lock (pool->queue); |
| } |
| } |
| else |
| { |
| /* No task was received, so this thread goes to the global pool. */ |
| gboolean free_pool = FALSE; |
| |
| DEBUG_MSG (("thread %p leaving pool %p for global pool.", |
| g_thread_self (), pool)); |
| pool->num_threads--; |
| |
| if (!pool->running) |
| { |
| if (!pool->waiting) |
| { |
| if (pool->num_threads == 0) |
| { |
| /* If the pool is not running and no other |
| * thread is waiting for this thread pool to |
| * finish and this is the last thread of this |
| * pool, free the pool. |
| */ |
| free_pool = TRUE; |
| } |
| else |
| { |
| /* If the pool is not running and no other |
| * thread is waiting for this thread pool to |
| * finish and this is not the last thread of |
| * this pool and there are no tasks left in the |
| * queue, wakeup the remaining threads. |
| */ |
| if (g_async_queue_length_unlocked (pool->queue) == |
| - pool->num_threads) |
| g_thread_pool_wakeup_and_stop_all (pool); |
| } |
| } |
| else if (pool->immediate || |
| g_async_queue_length_unlocked (pool->queue) <= 0) |
| { |
| /* If the pool is not running and another thread is |
| * waiting for this thread pool to finish and there |
| * are either no tasks left or the pool shall stop |
| * immediately, inform the waiting thread of a change |
| * of the thread pool state. |
| */ |
| g_cond_broadcast (&pool->cond); |
| } |
| } |
| |
| g_async_queue_unlock (pool->queue); |
| |
| if (free_pool) |
| g_thread_pool_free_internal (pool); |
| |
| if ((pool = g_thread_pool_wait_for_new_pool ()) == NULL) |
| break; |
| |
| g_async_queue_lock (pool->queue); |
| |
| DEBUG_MSG (("thread %p entering pool %p from global pool.", |
| g_thread_self (), pool)); |
| |
| /* pool->num_threads++ is not done here, but in |
| * g_thread_pool_start_thread to make the new started |
| * thread known to the pool before itself can do it. |
| */ |
| } |
| } |
| |
| return NULL; |
| } |
| |
| static gboolean |
| g_thread_pool_start_thread (GRealThreadPool *pool, |
| GError **error) |
| { |
| gboolean success = FALSE; |
| |
| if (pool->num_threads >= pool->max_threads && pool->max_threads != -1) |
| /* Enough threads are already running */ |
| return TRUE; |
| |
| g_async_queue_lock (unused_thread_queue); |
| |
| if (g_async_queue_length_unlocked (unused_thread_queue) < 0) |
| { |
| g_async_queue_push_unlocked (unused_thread_queue, pool); |
| success = TRUE; |
| } |
| |
| g_async_queue_unlock (unused_thread_queue); |
| |
| if (!success) |
| { |
| GThread *thread; |
| |
| /* No thread was found, we have to start a new one */ |
| thread = g_thread_try_new ("pool", g_thread_pool_thread_proxy, pool, error); |
| |
| if (thread == NULL) |
| return FALSE; |
| |
| g_thread_unref (thread); |
| } |
| |
| /* See comment in g_thread_pool_thread_proxy as to why this is done |
| * here and not there |
| */ |
| pool->num_threads++; |
| |
| return TRUE; |
| } |
| |
| /** |
| * g_thread_pool_new: |
| * @func: a function to execute in the threads of the new thread pool |
| * @user_data: user data that is handed over to @func every time it |
| * is called |
| * @max_threads: the maximal number of threads to execute concurrently |
| * in the new thread pool, -1 means no limit |
| * @exclusive: should this thread pool be exclusive? |
| * @error: return location for error, or %NULL |
| * |
| * This function creates a new thread pool. |
| * |
| * Whenever you call g_thread_pool_push(), either a new thread is |
| * created or an unused one is reused. At most @max_threads threads |
| * are running concurrently for this thread pool. @max_threads = -1 |
| * allows unlimited threads to be created for this thread pool. The |
| * newly created or reused thread now executes the function @func |
| * with the two arguments. The first one is the parameter to |
| * g_thread_pool_push() and the second one is @user_data. |
| * |
| * The parameter @exclusive determines whether the thread pool owns |
| * all threads exclusive or shares them with other thread pools. |
| * If @exclusive is %TRUE, @max_threads threads are started |
| * immediately and they will run exclusively for this thread pool |
| * until it is destroyed by g_thread_pool_free(). If @exclusive is |
| * %FALSE, threads are created when needed and shared between all |
| * non-exclusive thread pools. This implies that @max_threads may |
| * not be -1 for exclusive thread pools. Besides, exclusive thread |
| * pools are not affected by g_thread_pool_set_max_idle_time() |
| * since their threads are never considered idle and returned to the |
| * global pool. |
| * |
| * @error can be %NULL to ignore errors, or non-%NULL to report |
| * errors. An error can only occur when @exclusive is set to %TRUE |
| * and not all @max_threads threads could be created. |
| * See #GThreadError for possible errors that may occur. |
| * Note, even in case of error a valid #GThreadPool is returned. |
| * |
| * Returns: the new #GThreadPool |
| */ |
| GThreadPool * |
| g_thread_pool_new (GFunc func, |
| gpointer user_data, |
| gint max_threads, |
| gboolean exclusive, |
| GError **error) |
| { |
| GRealThreadPool *retval; |
| G_LOCK_DEFINE_STATIC (init); |
| |
| g_return_val_if_fail (func, NULL); |
| g_return_val_if_fail (!exclusive || max_threads != -1, NULL); |
| g_return_val_if_fail (max_threads >= -1, NULL); |
| |
| retval = g_new (GRealThreadPool, 1); |
| |
| retval->pool.func = func; |
| retval->pool.user_data = user_data; |
| retval->pool.exclusive = exclusive; |
| retval->queue = g_async_queue_new (); |
| g_cond_init (&retval->cond); |
| retval->max_threads = max_threads; |
| retval->num_threads = 0; |
| retval->running = TRUE; |
| retval->immediate = FALSE; |
| retval->waiting = FALSE; |
| retval->sort_func = NULL; |
| retval->sort_user_data = NULL; |
| |
| G_LOCK (init); |
| if (!unused_thread_queue) |
| unused_thread_queue = g_async_queue_new (); |
| G_UNLOCK (init); |
| |
| if (retval->pool.exclusive) |
| { |
| g_async_queue_lock (retval->queue); |
| |
| while (retval->num_threads < retval->max_threads) |
| { |
| GError *local_error = NULL; |
| |
| if (!g_thread_pool_start_thread (retval, &local_error)) |
| { |
| g_propagate_error (error, local_error); |
| break; |
| } |
| } |
| |
| g_async_queue_unlock (retval->queue); |
| } |
| |
| return (GThreadPool*) retval; |
| } |
| |
| /** |
| * g_thread_pool_push: |
| * @pool: a #GThreadPool |
| * @data: a new task for @pool |
| * @error: return location for error, or %NULL |
| * |
| * Inserts @data into the list of tasks to be executed by @pool. |
| * |
| * When the number of currently running threads is lower than the |
| * maximal allowed number of threads, a new thread is started (or |
| * reused) with the properties given to g_thread_pool_new(). |
| * Otherwise, @data stays in the queue until a thread in this pool |
| * finishes its previous task and processes @data. |
| * |
| * @error can be %NULL to ignore errors, or non-%NULL to report |
| * errors. An error can only occur when a new thread couldn't be |
| * created. In that case @data is simply appended to the queue of |
| * work to do. |
| * |
| * Before version 2.32, this function did not return a success status. |
| * |
| * Returns: %TRUE on success, %FALSE if an error occurred |
| */ |
| gboolean |
| g_thread_pool_push (GThreadPool *pool, |
| gpointer data, |
| GError **error) |
| { |
| GRealThreadPool *real; |
| gboolean result; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_val_if_fail (real, FALSE); |
| g_return_val_if_fail (real->running, FALSE); |
| |
| result = TRUE; |
| |
| g_async_queue_lock (real->queue); |
| |
| if (g_async_queue_length_unlocked (real->queue) >= 0) |
| { |
| /* No thread is waiting in the queue */ |
| GError *local_error = NULL; |
| |
| if (!g_thread_pool_start_thread (real, &local_error)) |
| { |
| g_propagate_error (error, local_error); |
| result = FALSE; |
| } |
| } |
| |
| g_thread_pool_queue_push_unlocked (real, data); |
| g_async_queue_unlock (real->queue); |
| |
| return result; |
| } |
| |
| /** |
| * g_thread_pool_set_max_threads: |
| * @pool: a #GThreadPool |
| * @max_threads: a new maximal number of threads for @pool, |
| * or -1 for unlimited |
| * @error: return location for error, or %NULL |
| * |
| * Sets the maximal allowed number of threads for @pool. |
| * A value of -1 means that the maximal number of threads |
| * is unlimited. If @pool is an exclusive thread pool, setting |
| * the maximal number of threads to -1 is not allowed. |
| * |
| * Setting @max_threads to 0 means stopping all work for @pool. |
| * It is effectively frozen until @max_threads is set to a non-zero |
| * value again. |
| * |
| * A thread is never terminated while calling @func, as supplied by |
| * g_thread_pool_new(). Instead the maximal number of threads only |
| * has effect for the allocation of new threads in g_thread_pool_push(). |
| * A new thread is allocated, whenever the number of currently |
| * running threads in @pool is smaller than the maximal number. |
| * |
| * @error can be %NULL to ignore errors, or non-%NULL to report |
| * errors. An error can only occur when a new thread couldn't be |
| * created. |
| * |
| * Before version 2.32, this function did not return a success status. |
| * |
| * Returns: %TRUE on success, %FALSE if an error occurred |
| */ |
| gboolean |
| g_thread_pool_set_max_threads (GThreadPool *pool, |
| gint max_threads, |
| GError **error) |
| { |
| GRealThreadPool *real; |
| gint to_start; |
| gboolean result; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_val_if_fail (real, FALSE); |
| g_return_val_if_fail (real->running, FALSE); |
| g_return_val_if_fail (!real->pool.exclusive || max_threads != -1, FALSE); |
| g_return_val_if_fail (max_threads >= -1, FALSE); |
| |
| result = TRUE; |
| |
| g_async_queue_lock (real->queue); |
| |
| real->max_threads = max_threads; |
| |
| if (pool->exclusive) |
| to_start = real->max_threads - real->num_threads; |
| else |
| to_start = g_async_queue_length_unlocked (real->queue); |
| |
| for ( ; to_start > 0; to_start--) |
| { |
| GError *local_error = NULL; |
| |
| if (!g_thread_pool_start_thread (real, &local_error)) |
| { |
| g_propagate_error (error, local_error); |
| result = FALSE; |
| break; |
| } |
| } |
| |
| g_async_queue_unlock (real->queue); |
| |
| return result; |
| } |
| |
| /** |
| * g_thread_pool_get_max_threads: |
| * @pool: a #GThreadPool |
| * |
| * Returns the maximal number of threads for @pool. |
| * |
| * Returns: the maximal number of threads |
| */ |
| gint |
| g_thread_pool_get_max_threads (GThreadPool *pool) |
| { |
| GRealThreadPool *real; |
| gint retval; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_val_if_fail (real, 0); |
| g_return_val_if_fail (real->running, 0); |
| |
| g_async_queue_lock (real->queue); |
| retval = real->max_threads; |
| g_async_queue_unlock (real->queue); |
| |
| return retval; |
| } |
| |
| /** |
| * g_thread_pool_get_num_threads: |
| * @pool: a #GThreadPool |
| * |
| * Returns the number of threads currently running in @pool. |
| * |
| * Returns: the number of threads currently running |
| */ |
| guint |
| g_thread_pool_get_num_threads (GThreadPool *pool) |
| { |
| GRealThreadPool *real; |
| guint retval; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_val_if_fail (real, 0); |
| g_return_val_if_fail (real->running, 0); |
| |
| g_async_queue_lock (real->queue); |
| retval = real->num_threads; |
| g_async_queue_unlock (real->queue); |
| |
| return retval; |
| } |
| |
| /** |
| * g_thread_pool_unprocessed: |
| * @pool: a #GThreadPool |
| * |
| * Returns the number of tasks still unprocessed in @pool. |
| * |
| * Returns: the number of unprocessed tasks |
| */ |
| guint |
| g_thread_pool_unprocessed (GThreadPool *pool) |
| { |
| GRealThreadPool *real; |
| gint unprocessed; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_val_if_fail (real, 0); |
| g_return_val_if_fail (real->running, 0); |
| |
| unprocessed = g_async_queue_length (real->queue); |
| |
| return MAX (unprocessed, 0); |
| } |
| |
| /** |
| * g_thread_pool_free: |
| * @pool: a #GThreadPool |
| * @immediate: should @pool shut down immediately? |
| * @wait_: should the function wait for all tasks to be finished? |
| * |
| * Frees all resources allocated for @pool. |
| * |
| * If @immediate is %TRUE, no new task is processed for @pool. |
| * Otherwise @pool is not freed before the last task is processed. |
| * Note however, that no thread of this pool is interrupted while |
| * processing a task. Instead at least all still running threads |
| * can finish their tasks before the @pool is freed. |
| * |
| * If @wait_ is %TRUE, the functions does not return before all |
| * tasks to be processed (dependent on @immediate, whether all |
| * or only the currently running) are ready. |
| * Otherwise the function returns immediately. |
| * |
| * After calling this function @pool must not be used anymore. |
| */ |
| void |
| g_thread_pool_free (GThreadPool *pool, |
| gboolean immediate, |
| gboolean wait_) |
| { |
| GRealThreadPool *real; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_if_fail (real); |
| g_return_if_fail (real->running); |
| |
| /* If there's no thread allowed here, there is not much sense in |
| * not stopping this pool immediately, when it's not empty |
| */ |
| g_return_if_fail (immediate || |
| real->max_threads != 0 || |
| g_async_queue_length (real->queue) == 0); |
| |
| g_async_queue_lock (real->queue); |
| |
| real->running = FALSE; |
| real->immediate = immediate; |
| real->waiting = wait_; |
| |
| if (wait_) |
| { |
| while (g_async_queue_length_unlocked (real->queue) != -real->num_threads && |
| !(immediate && real->num_threads == 0)) |
| g_cond_wait (&real->cond, _g_async_queue_get_mutex (real->queue)); |
| } |
| |
| if (immediate || g_async_queue_length_unlocked (real->queue) == -real->num_threads) |
| { |
| /* No thread is currently doing something (and nothing is left |
| * to process in the queue) |
| */ |
| if (real->num_threads == 0) |
| { |
| /* No threads left, we clean up */ |
| g_async_queue_unlock (real->queue); |
| g_thread_pool_free_internal (real); |
| return; |
| } |
| |
| g_thread_pool_wakeup_and_stop_all (real); |
| } |
| |
| /* The last thread should cleanup the pool */ |
| real->waiting = FALSE; |
| g_async_queue_unlock (real->queue); |
| } |
| |
| static void |
| g_thread_pool_free_internal (GRealThreadPool* pool) |
| { |
| g_return_if_fail (pool); |
| g_return_if_fail (pool->running == FALSE); |
| g_return_if_fail (pool->num_threads == 0); |
| |
| g_async_queue_unref (pool->queue); |
| g_cond_clear (&pool->cond); |
| |
| g_free (pool); |
| } |
| |
| static void |
| g_thread_pool_wakeup_and_stop_all (GRealThreadPool *pool) |
| { |
| guint i; |
| |
| g_return_if_fail (pool); |
| g_return_if_fail (pool->running == FALSE); |
| g_return_if_fail (pool->num_threads != 0); |
| |
| pool->immediate = TRUE; |
| |
| /* |
| * So here we're sending bogus data to the pool threads, which |
| * should cause them each to wake up, and check the above |
| * pool->immediate condition. However we don't want that |
| * data to be sorted (since it'll crash the sorter). |
| */ |
| for (i = 0; i < pool->num_threads; i++) |
| g_async_queue_push_unlocked (pool->queue, GUINT_TO_POINTER (1)); |
| } |
| |
| /** |
| * g_thread_pool_set_max_unused_threads: |
| * @max_threads: maximal number of unused threads |
| * |
| * Sets the maximal number of unused threads to @max_threads. |
| * If @max_threads is -1, no limit is imposed on the number |
| * of unused threads. |
| * |
| * The default value is 2. |
| */ |
| void |
| g_thread_pool_set_max_unused_threads (gint max_threads) |
| { |
| g_return_if_fail (max_threads >= -1); |
| |
| g_atomic_int_set (&max_unused_threads, max_threads); |
| |
| if (max_threads != -1) |
| { |
| max_threads -= g_atomic_int_get (&unused_threads); |
| if (max_threads < 0) |
| { |
| g_atomic_int_set (&kill_unused_threads, -max_threads); |
| g_atomic_int_inc (&wakeup_thread_serial); |
| |
| g_async_queue_lock (unused_thread_queue); |
| |
| do |
| { |
| g_async_queue_push_unlocked (unused_thread_queue, |
| wakeup_thread_marker); |
| } |
| while (++max_threads); |
| |
| g_async_queue_unlock (unused_thread_queue); |
| } |
| } |
| } |
| |
| /** |
| * g_thread_pool_get_max_unused_threads: |
| * |
| * Returns the maximal allowed number of unused threads. |
| * |
| * Returns: the maximal number of unused threads |
| */ |
| gint |
| g_thread_pool_get_max_unused_threads (void) |
| { |
| return g_atomic_int_get (&max_unused_threads); |
| } |
| |
| /** |
| * g_thread_pool_get_num_unused_threads: |
| * |
| * Returns the number of currently unused threads. |
| * |
| * Returns: the number of currently unused threads |
| */ |
| guint |
| g_thread_pool_get_num_unused_threads (void) |
| { |
| return g_atomic_int_get (&unused_threads); |
| } |
| |
| /** |
| * g_thread_pool_stop_unused_threads: |
| * |
| * Stops all currently unused threads. This does not change the |
| * maximal number of unused threads. This function can be used to |
| * regularly stop all unused threads e.g. from g_timeout_add(). |
| */ |
| void |
| g_thread_pool_stop_unused_threads (void) |
| { |
| guint oldval; |
| |
| oldval = g_thread_pool_get_max_unused_threads (); |
| |
| g_thread_pool_set_max_unused_threads (0); |
| g_thread_pool_set_max_unused_threads (oldval); |
| } |
| |
| /** |
| * g_thread_pool_set_sort_function: |
| * @pool: a #GThreadPool |
| * @func: the #GCompareDataFunc used to sort the list of tasks. |
| * This function is passed two tasks. It should return |
| * 0 if the order in which they are handled does not matter, |
| * a negative value if the first task should be processed before |
| * the second or a positive value if the second task should be |
| * processed first. |
| * @user_data: user data passed to @func |
| * |
| * Sets the function used to sort the list of tasks. This allows the |
| * tasks to be processed by a priority determined by @func, and not |
| * just in the order in which they were added to the pool. |
| * |
| * Note, if the maximum number of threads is more than 1, the order |
| * that threads are executed cannot be guaranteed 100%. Threads are |
| * scheduled by the operating system and are executed at random. It |
| * cannot be assumed that threads are executed in the order they are |
| * created. |
| * |
| * Since: 2.10 |
| */ |
| void |
| g_thread_pool_set_sort_function (GThreadPool *pool, |
| GCompareDataFunc func, |
| gpointer user_data) |
| { |
| GRealThreadPool *real; |
| |
| real = (GRealThreadPool*) pool; |
| |
| g_return_if_fail (real); |
| g_return_if_fail (real->running); |
| |
| g_async_queue_lock (real->queue); |
| |
| real->sort_func = func; |
| real->sort_user_data = user_data; |
| |
| if (func) |
| g_async_queue_sort_unlocked (real->queue, |
| real->sort_func, |
| real->sort_user_data); |
| |
| g_async_queue_unlock (real->queue); |
| } |
| |
| /** |
| * g_thread_pool_move_to_front: |
| * @pool: a #GThreadPool |
| * @data: an unprocessed item in the pool |
| * |
| * Moves the item to the front of the queue of unprocessed |
| * items, so that it will be processed next. |
| * |
| * Returns: %TRUE if the item was found and moved |
| * |
| * Since: 2.46 |
| */ |
| gboolean |
| g_thread_pool_move_to_front (GThreadPool *pool, |
| gpointer data) |
| { |
| GRealThreadPool *real = (GRealThreadPool*) pool; |
| gboolean found; |
| |
| g_async_queue_lock (real->queue); |
| |
| found = g_async_queue_remove_unlocked (real->queue, data); |
| if (found) |
| g_async_queue_push_front_unlocked (real->queue, data); |
| |
| g_async_queue_unlock (real->queue); |
| |
| return found; |
| } |
| |
| /** |
| * g_thread_pool_set_max_idle_time: |
| * @interval: the maximum @interval (in milliseconds) |
| * a thread can be idle |
| * |
| * This function will set the maximum @interval that a thread |
| * waiting in the pool for new tasks can be idle for before |
| * being stopped. This function is similar to calling |
| * g_thread_pool_stop_unused_threads() on a regular timeout, |
| * except this is done on a per thread basis. |
| * |
| * By setting @interval to 0, idle threads will not be stopped. |
| * |
| * The default value is 15000 (15 seconds). |
| * |
| * Since: 2.10 |
| */ |
| void |
| g_thread_pool_set_max_idle_time (guint interval) |
| { |
| guint i; |
| |
| g_atomic_int_set (&max_idle_time, interval); |
| |
| i = g_atomic_int_get (&unused_threads); |
| if (i > 0) |
| { |
| g_atomic_int_inc (&wakeup_thread_serial); |
| g_async_queue_lock (unused_thread_queue); |
| |
| do |
| { |
| g_async_queue_push_unlocked (unused_thread_queue, |
| wakeup_thread_marker); |
| } |
| while (--i); |
| |
| g_async_queue_unlock (unused_thread_queue); |
| } |
| } |
| |
| /** |
| * g_thread_pool_get_max_idle_time: |
| * |
| * This function will return the maximum @interval that a |
| * thread will wait in the thread pool for new tasks before |
| * being stopped. |
| * |
| * If this function returns 0, threads waiting in the thread |
| * pool for new work are not stopped. |
| * |
| * Returns: the maximum @interval (milliseconds) to wait |
| * for new tasks in the thread pool before stopping the |
| * thread |
| * |
| * Since: 2.10 |
| */ |
| guint |
| g_thread_pool_get_max_idle_time (void) |
| { |
| return g_atomic_int_get (&max_idle_time); |
| } |
