diff options
Diffstat (limited to 'third_party/abseil_cpp/absl/base/internal/spinlock_wait.h')
-rw-r--r-- | third_party/abseil_cpp/absl/base/internal/spinlock_wait.h | 93 |
1 files changed, 0 insertions, 93 deletions
diff --git a/third_party/abseil_cpp/absl/base/internal/spinlock_wait.h b/third_party/abseil_cpp/absl/base/internal/spinlock_wait.h deleted file mode 100644 index 169bc749fbc5..000000000000 --- a/third_party/abseil_cpp/absl/base/internal/spinlock_wait.h +++ /dev/null @@ -1,93 +0,0 @@ -// Copyright 2017 The Abseil Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// https://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -#ifndef ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_ -#define ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_ - -// Operations to make atomic transitions on a word, and to allow -// waiting for those transitions to become possible. - -#include <stdint.h> -#include <atomic> - -#include "absl/base/internal/scheduling_mode.h" - -namespace absl { -ABSL_NAMESPACE_BEGIN -namespace base_internal { - -// SpinLockWait() waits until it can perform one of several transitions from -// "from" to "to". It returns when it performs a transition where done==true. -struct SpinLockWaitTransition { - uint32_t from; - uint32_t to; - bool done; -}; - -// Wait until *w can transition from trans[i].from to trans[i].to for some i -// satisfying 0<=i<n && trans[i].done, atomically make the transition, -// then return the old value of *w. Make any other atomic transitions -// where !trans[i].done, but continue waiting. -uint32_t SpinLockWait(std::atomic<uint32_t> *w, int n, - const SpinLockWaitTransition trans[], - SchedulingMode scheduling_mode); - -// If possible, wake some thread that has called SpinLockDelay(w, ...). If -// "all" is true, wake all such threads. This call is a hint, and on some -// systems it may be a no-op; threads calling SpinLockDelay() will always wake -// eventually even if SpinLockWake() is never called. -void SpinLockWake(std::atomic<uint32_t> *w, bool all); - -// Wait for an appropriate spin delay on iteration "loop" of a -// spin loop on location *w, whose previously observed value was "value". -// SpinLockDelay() may do nothing, may yield the CPU, may sleep a clock tick, -// or may wait for a delay that can be truncated by a call to SpinLockWake(w). -// In all cases, it must return in bounded time even if SpinLockWake() is not -// called. -void SpinLockDelay(std::atomic<uint32_t> *w, uint32_t value, int loop, - base_internal::SchedulingMode scheduling_mode); - -// Helper used by AbslInternalSpinLockDelay. -// Returns a suggested delay in nanoseconds for iteration number "loop". -int SpinLockSuggestedDelayNS(int loop); - -} // namespace base_internal -ABSL_NAMESPACE_END -} // namespace absl - -// In some build configurations we pass --detect-odr-violations to the -// gold linker. This causes it to flag weak symbol overrides as ODR -// violations. Because ODR only applies to C++ and not C, -// --detect-odr-violations ignores symbols not mangled with C++ names. -// By changing our extension points to be extern "C", we dodge this -// check. -extern "C" { -void AbslInternalSpinLockWake(std::atomic<uint32_t> *w, bool all); -void AbslInternalSpinLockDelay( - std::atomic<uint32_t> *w, uint32_t value, int loop, - absl::base_internal::SchedulingMode scheduling_mode); -} - -inline void absl::base_internal::SpinLockWake(std::atomic<uint32_t> *w, - bool all) { - AbslInternalSpinLockWake(w, all); -} - -inline void absl::base_internal::SpinLockDelay( - std::atomic<uint32_t> *w, uint32_t value, int loop, - absl::base_internal::SchedulingMode scheduling_mode) { - AbslInternalSpinLockDelay(w, value, loop, scheduling_mode); -} - -#endif // ABSL_BASE_INTERNAL_SPINLOCK_WAIT_H_ |