diff options
Diffstat (limited to 'contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc')
| -rw-r--r-- | contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc | 122 |
1 files changed, 61 insertions, 61 deletions
diff --git a/contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc b/contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc index f32a54a7ea..202f7cdfc8 100644 --- a/contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc +++ b/contrib/restricted/abseil-cpp/absl/base/internal/spinlock_linux.inc @@ -1,51 +1,51 @@ -// Copyright 2018 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. -// -// This file is a Linux-specific part of spinlock_wait.cc - -#include <linux/futex.h> -#include <sys/syscall.h> -#include <unistd.h> - -#include <atomic> -#include <climits> -#include <cstdint> -#include <ctime> - -#include "absl/base/attributes.h" +// Copyright 2018 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. +// +// This file is a Linux-specific part of spinlock_wait.cc + +#include <linux/futex.h> +#include <sys/syscall.h> +#include <unistd.h> + +#include <atomic> +#include <climits> +#include <cstdint> +#include <ctime> + +#include "absl/base/attributes.h" #include "absl/base/internal/errno_saver.h" - -// The SpinLock lockword is `std::atomic<uint32_t>`. Here we assert that -// `std::atomic<uint32_t>` is bitwise equivalent of the `int` expected -// by SYS_futex. We also assume that reads/writes done to the lockword -// by SYS_futex have rational semantics with regard to the -// std::atomic<> API. C++ provides no guarantees of these assumptions, -// but they are believed to hold in practice. -static_assert(sizeof(std::atomic<uint32_t>) == sizeof(int), - "SpinLock lockword has the wrong size for a 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_PRIVATE_FLAG -#define FUTEX_PRIVATE_FLAG 128 -#endif -#endif - + +// The SpinLock lockword is `std::atomic<uint32_t>`. Here we assert that +// `std::atomic<uint32_t>` is bitwise equivalent of the `int` expected +// by SYS_futex. We also assume that reads/writes done to the lockword +// by SYS_futex have rational semantics with regard to the +// std::atomic<> API. C++ provides no guarantees of these assumptions, +// but they are believed to hold in practice. +static_assert(sizeof(std::atomic<uint32_t>) == sizeof(int), + "SpinLock lockword has the wrong size for a 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_PRIVATE_FLAG +#define FUTEX_PRIVATE_FLAG 128 +#endif +#endif + #if defined(__NR_futex_time64) && !defined(SYS_futex_time64) #define SYS_futex_time64 __NR_futex_time64 #endif @@ -54,21 +54,21 @@ static_assert(sizeof(std::atomic<uint32_t>) == sizeof(int), #define SYS_futex SYS_futex_time64 #endif -extern "C" { - +extern "C" { + ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)( - std::atomic<uint32_t> *w, uint32_t value, int loop, - absl::base_internal::SchedulingMode) { + std::atomic<uint32_t> *w, uint32_t value, int loop, + 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); -} - + 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); +} + ABSL_ATTRIBUTE_WEAK void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockWake)( std::atomic<uint32_t> *w, bool all) { - syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0); -} - -} // extern "C" + syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0); +} + +} // extern "C" |