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Diffstat (limited to 'absl/synchronization/internal/waiter.cc')
-rw-r--r--absl/synchronization/internal/waiter.cc66
1 files changed, 1 insertions, 65 deletions
diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc
index b6150b9b..2123be60 100644
--- a/absl/synchronization/internal/waiter.cc
+++ b/absl/synchronization/internal/waiter.cc
@@ -48,6 +48,7 @@
#include "absl/base/optimization.h"
#include "absl/synchronization/internal/kernel_timeout.h"
+
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace synchronization_internal {
@@ -66,71 +67,6 @@ static void MaybeBecomeIdle() {
#if ABSL_WAITER_MODE == ABSL_WAITER_MODE_FUTEX
-// Some Android headers are missing these definitions even though they
-// support these futex operations.
-#ifdef __BIONIC__
-#ifndef SYS_futex
-#define SYS_futex __NR_futex
-#endif
-#ifndef FUTEX_WAIT_BITSET
-#define FUTEX_WAIT_BITSET 9
-#endif
-#ifndef FUTEX_PRIVATE_FLAG
-#define FUTEX_PRIVATE_FLAG 128
-#endif
-#ifndef FUTEX_CLOCK_REALTIME
-#define FUTEX_CLOCK_REALTIME 256
-#endif
-#ifndef FUTEX_BITSET_MATCH_ANY
-#define FUTEX_BITSET_MATCH_ANY 0xFFFFFFFF
-#endif
-#endif
-
-#if defined(__NR_futex_time64) && !defined(SYS_futex_time64)
-#define SYS_futex_time64 __NR_futex_time64
-#endif
-
-#if defined(SYS_futex_time64) && !defined(SYS_futex)
-#define SYS_futex SYS_futex_time64
-#endif
-
-class Futex {
- public:
- static int WaitUntil(std::atomic<int32_t> *v, int32_t val,
- KernelTimeout t) {
- int err = 0;
- if (t.has_timeout()) {
- // https://locklessinc.com/articles/futex_cheat_sheet/
- // Unlike FUTEX_WAIT, FUTEX_WAIT_BITSET uses absolute time.
- struct timespec abs_timeout = t.MakeAbsTimespec();
- // Atomically check that the futex value is still 0, and if it
- // is, sleep until abs_timeout or until woken by FUTEX_WAKE.
- err = syscall(
- SYS_futex, reinterpret_cast<int32_t *>(v),
- FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME, val,
- &abs_timeout, nullptr, FUTEX_BITSET_MATCH_ANY);
- } else {
- // Atomically check that the futex value is still 0, and if it
- // is, sleep until woken by FUTEX_WAKE.
- err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
- FUTEX_WAIT | FUTEX_PRIVATE_FLAG, val, nullptr);
- }
- if (err != 0) {
- err = -errno;
- }
- return err;
- }
-
- static int Wake(std::atomic<int32_t> *v, int32_t count) {
- int err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v),
- FUTEX_WAKE | FUTEX_PRIVATE_FLAG, count);
- if (ABSL_PREDICT_FALSE(err < 0)) {
- err = -errno;
- }
- return err;
- }
-};
-
Waiter::Waiter() {
futex_.store(0, std::memory_order_relaxed);
}