[kernel][dlog] Logically remove zx_log_record_t rollout field
zx_log_record_t's rollout field is not used. Rename the field to
unused. A future CL will replace the field with a sequence ID that can
be used to calculate the number of dropped messages.
Bug: 69290
Change-Id: Ieaa0bd85667fb9ad5d23849ae79c516a71954264
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/484620
Commit-Queue: Nick Maniscalco <maniscalco@google.com>
Reviewed-by: Miguel Flores <miguelfrde@google.com>
Reviewed-by: Christopher Johnson <crjohns@google.com>
Reviewed-by: Tyler Mandry <tmandry@google.com>
diff --git a/docs/reference/syscalls/debuglog_read.md b/docs/reference/syscalls/debuglog_read.md
index 56d5dff..76b1f48 100644
--- a/docs/reference/syscalls/debuglog_read.md
+++ b/docs/reference/syscalls/debuglog_read.md
@@ -34,7 +34,7 @@
```c
typedef struct zx_log_record {
- uint32_t rollout;
+ uint32_t unused;
uint16_t datalen;
uint8_t severity;
uint8_t flags;
@@ -49,10 +49,6 @@
| Field | Description |
| ----------- | -------------------------------------------------------------- |
-| *rollout* | Number of bytes of log messages (including headers) dropped |
-: : since the last call to `zx_debuglog_read` on this object. The :
-: : kernel will drop the oldest log messages when its internal :
-: : buffer becomes full. :
| *datalen* | Number of bytes of data in the *data* field. |
| *severity* | Severity of this log message. Standard severity levels are |
: : defined in the header `zircon/syscalls/log.h`. :
diff --git a/src/diagnostics/archivist/src/fuzzer.rs b/src/diagnostics/archivist/src/fuzzer.rs
index 2057754..5fc1711 100644
--- a/src/diagnostics/archivist/src/fuzzer.rs
+++ b/src/diagnostics/archivist/src/fuzzer.rs
@@ -21,7 +21,7 @@
impl Arbitrary for RandomLogRecord {
fn arbitrary(u: &mut Unstructured<'_>) -> Result<Self> {
- let rollout = u32::arbitrary(u)?;
+ let unused = u32::arbitrary(u)?;
let datalen = u16::arbitrary(u)?;
let severity = u8::arbitrary(u)?;
let flags = u8::arbitrary(u)?;
@@ -35,7 +35,7 @@
u.fill_buffer(&mut partial)?;
Ok(RandomLogRecord(zx::sys::zx_log_record_t {
- rollout,
+ unused,
datalen,
severity,
flags,
diff --git a/src/diagnostics/archivist/src/logs/testing.rs b/src/diagnostics/archivist/src/logs/testing.rs
index 7f0f779..d1b2c09 100644
--- a/src/diagnostics/archivist/src/logs/testing.rs
+++ b/src/diagnostics/archivist/src/logs/testing.rs
@@ -487,7 +487,7 @@
pub fn new(log_data: &[u8]) -> Self {
let mut rec = zx::sys::zx_log_record_t::default();
let len = rec.data.len().min(log_data.len());
- rec.rollout = 0;
+ rec.unused = 0;
rec.datalen = len as u16;
rec.flags = TEST_KLOG_FLAGS;
rec.timestamp = TEST_KLOG_TIMESTAMP;
diff --git a/src/lib/zircon/rust/fuchsia-zircon-types/src/lib.rs b/src/lib/zircon/rust/fuchsia-zircon-types/src/lib.rs
index 7744781..6b9fe7d 100644
--- a/src/lib/zircon/rust/fuchsia-zircon-types/src/lib.rs
+++ b/src/lib/zircon/rust/fuchsia-zircon-types/src/lib.rs
@@ -1228,7 +1228,7 @@
#[repr(C)]
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub struct <zx_log_record_t> {
- pub rollout: u32,
+ pub unused: u32,
pub datalen: u16,
pub severity: u8,
pub flags: u8,
@@ -1244,7 +1244,7 @@
impl Default for zx_log_record_t {
fn default() -> zx_log_record_t {
zx_log_record_t {
- rollout: 0,
+ unused: 0,
datalen: 0,
severity: 0,
flags: 0,
diff --git a/zircon/kernel/lib/debuglog/debuglog.cc b/zircon/kernel/lib/debuglog/debuglog.cc
index c3e7a812..d5b0c26 100644
--- a/zircon/kernel/lib/debuglog/debuglog.cc
+++ b/zircon/kernel/lib/debuglog/debuglog.cc
@@ -228,14 +228,12 @@
Guard<SpinLock, IrqSave> guard{&log->lock};
size_t rtail = tail_;
- uint32_t rolled_out = 0;
// If the read-tail is not within the range of log-tail..log-head
// this reader has been lapped by a writer and we reset our read-tail
// to the current log-tail.
//
if ((log->head - log->tail) < (log->head - rtail)) {
- rolled_out = static_cast<uint32_t>(log->tail - rtail);
rtail = log->tail;
}
@@ -255,7 +253,7 @@
memcpy(record, record_start, fifospace);
memcpy(reinterpret_cast<char*>(record) + fifospace, log->data, actual - fifospace);
}
- record->hdr.preamble = rolled_out;
+ record->hdr.preamble = 0;
*_actual = actual;
status = ZX_OK;
diff --git a/zircon/kernel/lib/debuglog/debuglog_tests.cc b/zircon/kernel/lib/debuglog/debuglog_tests.cc
index 81c044b..173af89 100644
--- a/zircon/kernel/lib/debuglog/debuglog_tests.cc
+++ b/zircon/kernel/lib/debuglog/debuglog_tests.cc
@@ -119,7 +119,8 @@
END_TEST;
}
-bool log_reader_rollout() {
+// Write to the log, exceeding its capacity and see that data is lost.
+bool log_reader_dataloss() {
BEGIN_TEST;
fbl::AllocChecker ac;
@@ -165,11 +166,7 @@
num_read++;
ASSERT_EQ(sizeof(dlog_header) + sizeof(msg), got);
EXPECT_EQ(DEBUGLOG_WARNING, rec.hdr.severity);
- if (num_read == 1) {
- EXPECT_EQ(sizeof(dlog_header_t) + sizeof(msg), rec.hdr.preamble);
- } else {
- EXPECT_EQ(0u, rec.hdr.preamble);
- }
+ EXPECT_EQ(0u, rec.hdr.preamble);
EXPECT_EQ(0, rec.hdr.flags);
EXPECT_EQ(ZX_KOID_INVALID, rec.hdr.pid);
EXPECT_NE(ZX_KOID_INVALID, rec.hdr.tid);
@@ -236,6 +233,6 @@
DEBUGLOG_UNITTEST(log_format)
DEBUGLOG_UNITTEST(log_wrap)
DEBUGLOG_UNITTEST(log_reader_read)
-DEBUGLOG_UNITTEST(log_reader_rollout)
+DEBUGLOG_UNITTEST(log_reader_dataloss)
DEBUGLOG_UNITTEST(shutdown)
UNITTEST_END_TESTCASE(debuglog_tests, "debuglog_tests", "Debuglog test")
diff --git a/zircon/kernel/lib/debuglog/include/lib/debuglog.h b/zircon/kernel/lib/debuglog/include/lib/debuglog.h
index 783472f..b4a884d 100644
--- a/zircon/kernel/lib/debuglog/include/lib/debuglog.h
+++ b/zircon/kernel/lib/debuglog/include/lib/debuglog.h
@@ -73,11 +73,7 @@
// (|DLOG_HDR_READLEN|) and the record's size when padded out to live in the
// FIFO (|DLOG_HDR_FIFOLEN|).
//
- // After being read out of a debuglog, the |preamble| field contains the
- // number of bytes (across both headers and messages) that were dropped from
- // the log since the last message was read. Note, this is a 32-bit value so if
- // approximately 4GB of data is written in between two read operations, data
- // loss may go undetected.
+ // After being read out of a debuglog, the |preamble| field is 0.
uint32_t preamble;
uint16_t datalen;
uint8_t severity;
diff --git a/zircon/system/public/zircon/syscalls/log.h b/zircon/system/public/zircon/syscalls/log.h
index 0f72348..a60649e 100644
--- a/zircon/system/public/zircon/syscalls/log.h
+++ b/zircon/system/public/zircon/syscalls/log.h
@@ -11,7 +11,7 @@
// Defines and structures for zx_log_*()
typedef struct zx_log_record {
- uint32_t rollout;
+ uint32_t unused;
uint16_t datalen;
uint8_t severity;
uint8_t flags;
