Stop using sleep timeouts for Linux futex-based SpinLock
Timeouts were once necessary when the SpinLock Unlock used an atomic
store and could therefore have a race and a missed wakeup, however,
the Unlock path now uses an atomic exchange, so the missed wakeup
cannot happen.
Fixes #1179
PiperOrigin-RevId: 452047517
Change-Id: I844944879b51b7f7ddac148e063a376cddd0d05a
diff --git a/absl/base/internal/spinlock_linux.inc b/absl/base/internal/spinlock_linux.inc
index 202f7cd..fe8ba67 100644
--- a/absl/base/internal/spinlock_linux.inc
+++ b/absl/base/internal/spinlock_linux.inc
@@ -57,13 +57,10 @@
extern "C" {
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
- std::atomic<uint32_t> *w, uint32_t value, int loop,
+ std::atomic<uint32_t> *w, uint32_t value, int,
absl::base_internal::SchedulingMode) {
absl::base_internal::ErrnoSaver errno_saver;
- struct timespec tm;
- tm.tv_sec = 0;
- tm.tv_nsec = absl::base_internal::SpinLockSuggestedDelayNS(loop);
- syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, &tm);
+ syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, nullptr);
}
ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)(
