Export of internal Abseil changes.
-- c508ee8bcc38dad1019c0ad744c47ac70efd36b7 by Derek Mauro <dmauro@google.com>: Opensource the Linux specific SpinLock Wait/Wake implementation. PiperOrigin-RevId: 209420888 -- c13113e19973d496f3e798c0e6d5569c78e41466 by Derek Mauro <dmauro@google.com>: Fix build error from https://github.com/abseil/abseil-cpp/issues/159 PiperOrigin-RevId: 209152118 GitOrigin-RevId: c508ee8bcc38dad1019c0ad744c47ac70efd36b7 Change-Id: I1a287df973198f9e26936d8f91031bb354db0c71
This commit is contained in:
		
							parent
							
								
									ad5c960b2e
								
							
						
					
					
						commit
						d8cfe9f2a7
					
				
					 5 changed files with 80 additions and 3 deletions
				
			
		| 
						 | 
					@ -30,6 +30,7 @@ cc_library(
 | 
				
			||||||
    name = "spinlock_wait",
 | 
					    name = "spinlock_wait",
 | 
				
			||||||
    srcs = [
 | 
					    srcs = [
 | 
				
			||||||
        "internal/spinlock_akaros.inc",
 | 
					        "internal/spinlock_akaros.inc",
 | 
				
			||||||
 | 
					        "internal/spinlock_linux.inc",
 | 
				
			||||||
        "internal/spinlock_posix.inc",
 | 
					        "internal/spinlock_posix.inc",
 | 
				
			||||||
        "internal/spinlock_wait.cc",
 | 
					        "internal/spinlock_wait.cc",
 | 
				
			||||||
        "internal/spinlock_win32.inc",
 | 
					        "internal/spinlock_win32.inc",
 | 
				
			||||||
| 
						 | 
					
 | 
				
			||||||
							
								
								
									
										72
									
								
								absl/base/internal/spinlock_linux.inc
									
										
									
									
									
										Normal file
									
								
							
							
						
						
									
										72
									
								
								absl/base/internal/spinlock_linux.inc
									
										
									
									
									
										Normal file
									
								
							| 
						 | 
					@ -0,0 +1,72 @@
 | 
				
			||||||
 | 
					// 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
 | 
				
			||||||
 | 
					//
 | 
				
			||||||
 | 
					//      http://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 <cerrno>
 | 
				
			||||||
 | 
					#include <climits>
 | 
				
			||||||
 | 
					#include <cstdint>
 | 
				
			||||||
 | 
					#include <ctime>
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					#include "absl/base/attributes.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
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					extern "C" {
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockDelay(
 | 
				
			||||||
 | 
					    std::atomic<uint32_t> *w, uint32_t value, int loop,
 | 
				
			||||||
 | 
					    absl::base_internal::SchedulingMode) {
 | 
				
			||||||
 | 
					  if (loop != 0) {
 | 
				
			||||||
 | 
					    int save_errno = errno;
 | 
				
			||||||
 | 
					    struct timespec tm;
 | 
				
			||||||
 | 
					    tm.tv_sec = 0;
 | 
				
			||||||
 | 
					    // Increase the delay; we expect (but do not rely on) explicit wakeups.
 | 
				
			||||||
 | 
					    // We don't rely on explicit wakeups because we intentionally allow for
 | 
				
			||||||
 | 
					    // a race on the kSpinLockSleeper bit.
 | 
				
			||||||
 | 
					    tm.tv_nsec = 16 * absl::base_internal::SpinLockSuggestedDelayNS(loop);
 | 
				
			||||||
 | 
					    syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, &tm);
 | 
				
			||||||
 | 
					    errno = save_errno;
 | 
				
			||||||
 | 
					  }
 | 
				
			||||||
 | 
					}
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockWake(std::atomic<uint32_t> *w,
 | 
				
			||||||
 | 
					                                                  bool all) {
 | 
				
			||||||
 | 
					  syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0);
 | 
				
			||||||
 | 
					}
 | 
				
			||||||
 | 
					
 | 
				
			||||||
 | 
					}  // extern "C"
 | 
				
			||||||
| 
						 | 
					@ -13,7 +13,7 @@
 | 
				
			||||||
// limitations under the License.
 | 
					// limitations under the License.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
// The OS-specific header included below must provide two calls:
 | 
					// The OS-specific header included below must provide two calls:
 | 
				
			||||||
// base::subtle::SpinLockDelay() and base::subtle::SpinLockWake().
 | 
					// AbslInternalSpinLockDelay() and AbslInternalSpinLockWake().
 | 
				
			||||||
// See spinlock_wait.h for the specs.
 | 
					// See spinlock_wait.h for the specs.
 | 
				
			||||||
 | 
					
 | 
				
			||||||
#include <atomic>
 | 
					#include <atomic>
 | 
				
			||||||
| 
						 | 
					@ -23,6 +23,8 @@
 | 
				
			||||||
 | 
					
 | 
				
			||||||
#if defined(_WIN32)
 | 
					#if defined(_WIN32)
 | 
				
			||||||
#include "absl/base/internal/spinlock_win32.inc"
 | 
					#include "absl/base/internal/spinlock_win32.inc"
 | 
				
			||||||
 | 
					#elif defined(__linux__)
 | 
				
			||||||
 | 
					#include "absl/base/internal/spinlock_linux.inc"
 | 
				
			||||||
#elif defined(__akaros__)
 | 
					#elif defined(__akaros__)
 | 
				
			||||||
#include "absl/base/internal/spinlock_akaros.inc"
 | 
					#include "absl/base/internal/spinlock_akaros.inc"
 | 
				
			||||||
#else
 | 
					#else
 | 
				
			||||||
| 
						 | 
					
 | 
				
			||||||
| 
						 | 
					@ -28,7 +28,8 @@
 | 
				
			||||||
#define ABSL_EXPECT_DEBUG_DEATH(statement, regex) \
 | 
					#define ABSL_EXPECT_DEBUG_DEATH(statement, regex) \
 | 
				
			||||||
  EXPECT_DEBUG_DEATH(statement, ".*")
 | 
					  EXPECT_DEBUG_DEATH(statement, ".*")
 | 
				
			||||||
#else
 | 
					#else
 | 
				
			||||||
#define ABSL_EXPECT_DEBUG_DEATH EXPECT_DEBUG_DEATH
 | 
					#define ABSL_EXPECT_DEBUG_DEATH(statement, regex) \
 | 
				
			||||||
 | 
					  EXPECT_DEBUG_DEATH(statement, regex)
 | 
				
			||||||
#endif
 | 
					#endif
 | 
				
			||||||
 | 
					
 | 
				
			||||||
namespace {
 | 
					namespace {
 | 
				
			||||||
| 
						 | 
					
 | 
				
			||||||
| 
						 | 
					@ -35,7 +35,8 @@
 | 
				
			||||||
#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
 | 
					#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
 | 
				
			||||||
  EXPECT_DEATH_IF_SUPPORTED(statement, ".*")
 | 
					  EXPECT_DEATH_IF_SUPPORTED(statement, ".*")
 | 
				
			||||||
#else
 | 
					#else
 | 
				
			||||||
#define ABSL_EXPECT_DEATH_IF_SUPPORTED EXPECT_DEATH_IF_SUPPORTED
 | 
					#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
 | 
				
			||||||
 | 
					  EXPECT_DEATH_IF_SUPPORTED(statement, regex)
 | 
				
			||||||
#endif
 | 
					#endif
 | 
				
			||||||
 | 
					
 | 
				
			||||||
namespace {
 | 
					namespace {
 | 
				
			||||||
| 
						 | 
					
 | 
				
			||||||
		Loading…
	
	Add table
		Add a link
		
	
		Reference in a new issue