Skip to content

A
abseil-cpp
Commit 1a72ea7b by Derek Mauro Committed by Copybara-Service
Options

Synchronization: Support true relative timeouts using the POSIX 

proposed standard pthread_cond_clockwait() and sem_clockwait().
These are currently implemented in glibc >= 2.30.

These methods take a clock and use an absolute time with reference
to that clock, so KernelTimeout now can produce these values.

PiperOrigin-RevId: 522824226
Change-Id: Ife98713f6f95d800b1f8e52d5364a3dbebc4f8a6
parent 42a3c030
Showing with 150 additions and 11 deletions
absl/synchronization/internal/kernel_timeout.cc
...@@ -14,6 +14,10 @@ ...@@ -14,6 +14,10 @@
#include "absl/synchronization/internal/kernel_timeout.h" #include "absl/synchronization/internal/kernel_timeout.h"
#ifndef _WIN32
#include <sys/types.h>
#endif
#include <algorithm> #include <algorithm>
#include <chrono> // NOLINT(build/c++11) #include <chrono> // NOLINT(build/c++11)
#include <cstdint> #include <cstdint>
...@@ -101,7 +105,7 @@ int64_t KernelTimeout::MakeAbsNanos() const { ...@@ -101,7 +105,7 @@ int64_t KernelTimeout::MakeAbsNanos() const {
return kMaxNanos; return kMaxNanos;
} }
int64_t nanos = RawNanos(); int64_t nanos = RawAbsNanos();
if (is_relative_timeout()) { if (is_relative_timeout()) {
// We need to change epochs, because the relative timeout might be // We need to change epochs, because the relative timeout might be
...@@ -128,7 +132,7 @@ int64_t KernelTimeout::InNanosecondsFromNow() const { ...@@ -128,7 +132,7 @@ int64_t KernelTimeout::InNanosecondsFromNow() const {
return kMaxNanos; return kMaxNanos;
} }
int64_t nanos = RawNanos(); int64_t nanos = RawAbsNanos();
if (is_absolute_timeout()) { if (is_absolute_timeout()) {
return std::max<int64_t>(nanos - absl::GetCurrentTimeNanos(), 0); return std::max<int64_t>(nanos - absl::GetCurrentTimeNanos(), 0);
} }
...@@ -143,6 +147,33 @@ struct timespec KernelTimeout::MakeRelativeTimespec() const { ...@@ -143,6 +147,33 @@ struct timespec KernelTimeout::MakeRelativeTimespec() const {
return absl::ToTimespec(absl::Nanoseconds(InNanosecondsFromNow())); return absl::ToTimespec(absl::Nanoseconds(InNanosecondsFromNow()));
} }
#ifndef _WIN32
struct timespec KernelTimeout::MakeClockAbsoluteTimespec(clockid_t c) const {
if (!has_timeout()) {
return absl::ToTimespec(absl::Nanoseconds(kMaxNanos));
}
int64_t nanos = RawAbsNanos();
if (is_absolute_timeout()) {
nanos -= absl::GetCurrentTimeNanos();
} else {
nanos -= SteadyClockNow();
}
struct timespec now;
ABSL_RAW_CHECK(clock_gettime(c, &now) == 0, "clock_gettime() failed");
absl::Duration from_clock_epoch =
absl::DurationFromTimespec(now) + absl::Nanoseconds(nanos);
if (from_clock_epoch <= absl::ZeroDuration()) {
// Some callers have assumed that 0 means no timeout, so instead we return a
// time of 1 nanosecond after the epoch. For safety we also do not return
// negative values.
return absl::ToTimespec(absl::Nanoseconds(1));
}
return absl::ToTimespec(from_clock_epoch);
}
#endif
KernelTimeout::DWord KernelTimeout::InMillisecondsFromNow() const { KernelTimeout::DWord KernelTimeout::InMillisecondsFromNow() const {
constexpr DWord kInfinite = std::numeric_limits<DWord>::max(); constexpr DWord kInfinite = std::numeric_limits<DWord>::max();
......
absl/synchronization/internal/kernel_timeout.h
...@@ -15,6 +15,10 @@ ...@@ -15,6 +15,10 @@
#ifndef ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_ #ifndef ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_
#define ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_ #define ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_
#ifndef _WIN32
#include <sys/types.h>
#endif
#include <algorithm> #include <algorithm>
#include <chrono> // NOLINT(build/c++11) #include <chrono> // NOLINT(build/c++11)
#include <cstdint> #include <cstdint>
...@@ -78,6 +82,18 @@ class KernelTimeout { ...@@ -78,6 +82,18 @@ class KernelTimeout {
// this method in the case of a spurious wakeup. // this method in the case of a spurious wakeup.
struct timespec MakeRelativeTimespec() const; struct timespec MakeRelativeTimespec() const;
#ifndef _WIN32
// Convert to `struct timespec` for interfaces that expect an absolute timeout
// on a specific clock `c`. This is similar to `MakeAbsTimespec()`, but
// callers usually want to use this method with `CLOCK_MONOTONIC` when
// relative timeouts are requested, and when the appropriate interface expects
// an absolute timeout relative to a specific clock (for example,
// pthread_cond_clockwait() or sem_clockwait()). If !has_timeout(), attempts
// to convert to a reasonable absolute timeout, but callers should to test
// has_timeout() prefer to use a more appropriate interface.
struct timespec MakeClockAbsoluteTimespec(clockid_t c) const;
#endif
// Convert to unix epoch nanos for interfaces that expect an absolute timeout // Convert to unix epoch nanos for interfaces that expect an absolute timeout
// in nanoseconds. If !has_timeout() or is_relative_timeout(), attempts to // in nanoseconds. If !has_timeout() or is_relative_timeout(), attempts to
// convert to a reasonable absolute timeout, but callers should to test // convert to a reasonable absolute timeout, but callers should to test
...@@ -125,12 +141,18 @@ class KernelTimeout { ...@@ -125,12 +141,18 @@ class KernelTimeout {
// after the unix epoch. // after the unix epoch.
// - If the low bit is 1, then the high 63 bits is the number of nanoseconds // - If the low bit is 1, then the high 63 bits is the number of nanoseconds
// after the epoch used by SteadyClockNow(). // after the epoch used by SteadyClockNow().
//
// In all cases the time is stored as an absolute time, the only difference is
// the clock epoch. The use of absolute times is important since in the case
// of a relative timeout with a spurious wakeup, the program would have to
// restart the wait, and thus needs a way of recomputing the remaining time.
uint64_t rep_; uint64_t rep_;
// Returns the number of nanoseconds stored in the internal representation. // Returns the number of nanoseconds stored in the internal representation.
// Together with is_absolute_timeout() and is_relative_timeout(), the return // When combined with the clock epoch indicated by the low bit (which is
// value is used to compute when the timeout should occur. // accessed through is_absolute_timeout() and is_relative_timeout()), the
int64_t RawNanos() const { return static_cast<int64_t>(rep_ >> 1); } // return value is used to compute when the timeout should occur.
int64_t RawAbsNanos() const { return static_cast<int64_t>(rep_ >> 1); }
// Converts to nanoseconds from now. Since the return value is a relative // Converts to nanoseconds from now. Since the return value is a relative
// duration, it should be recomputed by calling this method in the case of a // duration, it should be recomputed by calling this method in the case of a
......
absl/synchronization/internal/kernel_timeout_test.cc
...@@ -64,6 +64,13 @@ TEST(KernelTimeout, FiniteTimes) { ...@@ -64,6 +64,13 @@ TEST(KernelTimeout, FiniteTimes) {
EXPECT_TRUE(t.is_absolute_timeout()); EXPECT_TRUE(t.is_absolute_timeout());
EXPECT_FALSE(t.is_relative_timeout()); EXPECT_FALSE(t.is_relative_timeout());
EXPECT_EQ(absl::TimeFromTimespec(t.MakeAbsTimespec()), when); EXPECT_EQ(absl::TimeFromTimespec(t.MakeAbsTimespec()), when);
#ifndef _WIN32
EXPECT_LE(
absl::AbsDuration(absl::Now() + duration -
absl::TimeFromTimespec(
t.MakeClockAbsoluteTimespec(CLOCK_REALTIME))),
absl::Milliseconds(10));
#endif
EXPECT_LE( EXPECT_LE(
absl::AbsDuration(absl::DurationFromTimespec(t.MakeRelativeTimespec()) - absl::AbsDuration(absl::DurationFromTimespec(t.MakeRelativeTimespec()) -
std::max(duration, absl::ZeroDuration())), std::max(duration, absl::ZeroDuration())),
...@@ -89,6 +96,10 @@ TEST(KernelTimeout, InfiniteFuture) { ...@@ -89,6 +96,10 @@ TEST(KernelTimeout, InfiniteFuture) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -110,6 +121,10 @@ TEST(KernelTimeout, DefaultConstructor) { ...@@ -110,6 +121,10 @@ TEST(KernelTimeout, DefaultConstructor) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -131,6 +146,10 @@ TEST(KernelTimeout, TimeMaxNanos) { ...@@ -131,6 +146,10 @@ TEST(KernelTimeout, TimeMaxNanos) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -152,6 +171,10 @@ TEST(KernelTimeout, Never) { ...@@ -152,6 +171,10 @@ TEST(KernelTimeout, Never) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -170,6 +193,10 @@ TEST(KernelTimeout, InfinitePast) { ...@@ -170,6 +193,10 @@ TEST(KernelTimeout, InfinitePast) {
EXPECT_FALSE(t.is_relative_timeout()); EXPECT_FALSE(t.is_relative_timeout());
EXPECT_LE(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_LE(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::FromUnixNanos(1)); absl::FromUnixNanos(1));
#ifndef _WIN32
EXPECT_LE(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::FromUnixSeconds(1));
#endif
EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::ZeroDuration()); absl::ZeroDuration());
EXPECT_LE(absl::FromUnixNanos(t.MakeAbsNanos()), absl::FromUnixNanos(1)); EXPECT_LE(absl::FromUnixNanos(t.MakeAbsNanos()), absl::FromUnixNanos(1));
...@@ -200,6 +227,13 @@ TEST(KernelTimeout, FiniteDurations) { ...@@ -200,6 +227,13 @@ TEST(KernelTimeout, FiniteDurations) {
EXPECT_LE(absl::AbsDuration(absl::Now() + duration - EXPECT_LE(absl::AbsDuration(absl::Now() + duration -
absl::TimeFromTimespec(t.MakeAbsTimespec())), absl::TimeFromTimespec(t.MakeAbsTimespec())),
absl::Milliseconds(5)); absl::Milliseconds(5));
#ifndef _WIN32
EXPECT_LE(
absl::AbsDuration(absl::Now() + duration -
absl::TimeFromTimespec(
t.MakeClockAbsoluteTimespec(CLOCK_REALTIME))),
absl::Milliseconds(5));
#endif
EXPECT_LE( EXPECT_LE(
absl::AbsDuration(absl::DurationFromTimespec(t.MakeRelativeTimespec()) - absl::AbsDuration(absl::DurationFromTimespec(t.MakeRelativeTimespec()) -
duration), duration),
...@@ -241,6 +275,12 @@ TEST(KernelTimeout, NegativeDurations) { ...@@ -241,6 +275,12 @@ TEST(KernelTimeout, NegativeDurations) {
EXPECT_LE(absl::AbsDuration(absl::Now() - EXPECT_LE(absl::AbsDuration(absl::Now() -
absl::TimeFromTimespec(t.MakeAbsTimespec())), absl::TimeFromTimespec(t.MakeAbsTimespec())),
absl::Milliseconds(5)); absl::Milliseconds(5));
#ifndef _WIN32
EXPECT_LE(absl::AbsDuration(absl::Now() - absl::TimeFromTimespec(
t.MakeClockAbsoluteTimespec(
CLOCK_REALTIME))),
absl::Milliseconds(5));
#endif
EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::ZeroDuration()); absl::ZeroDuration());
EXPECT_LE( EXPECT_LE(
...@@ -263,6 +303,10 @@ TEST(KernelTimeout, InfiniteDuration) { ...@@ -263,6 +303,10 @@ TEST(KernelTimeout, InfiniteDuration) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -284,6 +328,10 @@ TEST(KernelTimeout, DurationMaxNanos) { ...@@ -284,6 +328,10 @@ TEST(KernelTimeout, DurationMaxNanos) {
// absl::InfiniteFuture(), but we should return a very large value. // absl::InfiniteFuture(), but we should return a very large value.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
...@@ -305,6 +353,10 @@ TEST(KernelTimeout, OverflowNanos) { ...@@ -305,6 +353,10 @@ TEST(KernelTimeout, OverflowNanos) {
// Timeouts should still be far in the future. // Timeouts should still be far in the future.
EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()),
absl::Now() + absl::Hours(100000)); absl::Now() + absl::Hours(100000));
#ifndef _WIN32
EXPECT_GT(absl::TimeFromTimespec(t.MakeClockAbsoluteTimespec(CLOCK_REALTIME)),
absl::Now() + absl::Hours(100000));
#endif
EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()),
absl::Hours(100000)); absl::Hours(100000));
EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()),
......
absl/synchronization/internal/pthread_waiter.cc
...@@ -78,6 +78,11 @@ PthreadWaiter::PthreadWaiter() : waiter_count_(0), wakeup_count_(0) { ...@@ -78,6 +78,11 @@ PthreadWaiter::PthreadWaiter() : waiter_count_(0), wakeup_count_(0) {
#define ABSL_INTERNAL_HAS_PTHREAD_COND_TIMEDWAIT_RELATIVE_NP 1 #define ABSL_INTERNAL_HAS_PTHREAD_COND_TIMEDWAIT_RELATIVE_NP 1
#endif #endif
#if defined(__GLIBC__) && \
(__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30))
#define ABSL_INTERNAL_HAVE_PTHREAD_COND_CLOCKWAIT 1
#endif
// Calls pthread_cond_timedwait() or possibly something else like // Calls pthread_cond_timedwait() or possibly something else like
// pthread_cond_timedwait_relative_np() depending on the platform and // pthread_cond_timedwait_relative_np() depending on the platform and
// KernelTimeout requested. The return value is the same as the return // KernelTimeout requested. The return value is the same as the return
...@@ -94,6 +99,11 @@ int PthreadWaiter::TimedWait(KernelTimeout t) { ...@@ -94,6 +99,11 @@ int PthreadWaiter::TimedWait(KernelTimeout t) {
#ifdef ABSL_INTERNAL_HAS_PTHREAD_COND_TIMEDWAIT_RELATIVE_NP #ifdef ABSL_INTERNAL_HAS_PTHREAD_COND_TIMEDWAIT_RELATIVE_NP
const auto rel_timeout = t.MakeRelativeTimespec(); const auto rel_timeout = t.MakeRelativeTimespec();
return pthread_cond_timedwait_relative_np(&cv_, &mu_, &rel_timeout); return pthread_cond_timedwait_relative_np(&cv_, &mu_, &rel_timeout);
#elif defined(ABSL_INTERNAL_HAVE_PTHREAD_COND_CLOCKWAIT) && \
defined(CLOCK_MONOTONIC)
const auto abs_clock_timeout = t.MakeClockAbsoluteTimespec(CLOCK_MONOTONIC);
return pthread_cond_clockwait(&cv_, &mu_, CLOCK_MONOTONIC,
&abs_clock_timeout);
#endif #endif
} }
......
absl/synchronization/internal/sem_waiter.cc
...@@ -43,12 +43,34 @@ SemWaiter::SemWaiter() : wakeups_(0) { ...@@ -43,12 +43,34 @@ SemWaiter::SemWaiter() : wakeups_(0) {
} }
} }
bool SemWaiter::Wait(KernelTimeout t) { #if defined(__GLIBC__) && \
struct timespec abs_timeout; (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30))
if (t.has_timeout()) { #define ABSL_INTERNAL_HAVE_SEM_CLOCKWAIT 1
abs_timeout = t.MakeAbsTimespec(); #endif
// Calls sem_timedwait() or possibly something else like
// sem_clockwait() depending on the platform and
// KernelTimeout requested. The return value is the same as a call to the return
// value to a call to sem_timedwait().
int SemWaiter::TimedWait(KernelTimeout t) {
#ifndef __GOOGLE_GRTE_VERSION__
constexpr bool kRelativeTimeoutSupported = true;
#else
constexpr bool kRelativeTimeoutSupported = false;
#endif
if (kRelativeTimeoutSupported && t.is_relative_timeout()) {
#if defined(ABSL_INTERNAL_HAVE_SEM_CLOCKWAIT) && defined(CLOCK_MONOTONIC)
const auto abs_clock_timeout = t.MakeClockAbsoluteTimespec(CLOCK_MONOTONIC);
return sem_clockwait(&sem_, CLOCK_MONOTONIC, &abs_clock_timeout);
#endif
} }
const auto abs_timeout = t.MakeAbsTimespec();
return sem_timedwait(&sem_, &abs_timeout);
}
bool SemWaiter::Wait(KernelTimeout t) {
// Loop until we timeout or consume a wakeup. // Loop until we timeout or consume a wakeup.
// Note that, since the thread ticker is just reset, we don't need to check // Note that, since the thread ticker is just reset, we don't need to check
// whether the thread is idle on the very first pass of the loop. // whether the thread is idle on the very first pass of the loop.
...@@ -73,10 +95,10 @@ bool SemWaiter::Wait(KernelTimeout t) { ...@@ -73,10 +95,10 @@ bool SemWaiter::Wait(KernelTimeout t) {
if (errno == EINTR) continue; if (errno == EINTR) continue;
ABSL_RAW_LOG(FATAL, "sem_wait failed: %d", errno); ABSL_RAW_LOG(FATAL, "sem_wait failed: %d", errno);
} else { } else {
if (sem_timedwait(&sem_, &abs_timeout) == 0) break; if (TimedWait(t) == 0) break;
if (errno == EINTR) continue; if (errno == EINTR) continue;
if (errno == ETIMEDOUT) return false; if (errno == ETIMEDOUT) return false;
ABSL_RAW_LOG(FATAL, "sem_timedwait failed: %d", errno); ABSL_RAW_LOG(FATAL, "SemWaiter::TimedWait() failed: %d", errno);
} }
} }
first_pass = false; first_pass = false;
......
absl/synchronization/internal/sem_waiter.h
...@@ -46,6 +46,8 @@ class SemWaiter : public WaiterCrtp<SemWaiter> { ...@@ -46,6 +46,8 @@ class SemWaiter : public WaiterCrtp<SemWaiter> {
static constexpr char kName[] = "SemWaiter"; static constexpr char kName[] = "SemWaiter";
private: private:
int TimedWait(KernelTimeout t);
sem_t sem_; sem_t sem_;
// This seems superfluous, but for Poke() we need to cause spurious // This seems superfluous, but for Poke() we need to cause spurious
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment