| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/private/SkSpinlock.h" |
| #include "include/private/base/SkThreadAnnotations.h" |
| |
| #if 0 |
| #include "include/private/base/SkMutex.h" |
| #include <execinfo.h> |
| #include <stdio.h> |
| |
| static void debug_trace() { |
| void* stack[64]; |
| int len = backtrace(stack, std::size(stack)); |
| |
| // As you might imagine, we can't use an SkSpinlock here... |
| static SkMutex lock; |
| { |
| SkAutoMutexExclusive locked(lock); |
| fprintf(stderr, "\n"); |
| backtrace_symbols_fd(stack, len, 2/*stderr*/); |
| fprintf(stderr, "\n"); |
| } |
| } |
| #else |
| static void debug_trace() {} |
| #endif |
| |
| // Renamed from "pause" to avoid conflict with function defined in unistd.h |
| #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2 |
| #include <emmintrin.h> |
| static void do_pause() { _mm_pause(); } |
| #else |
| static void do_pause() { /*spin*/ } |
| #endif |
| |
| void SkSpinlock::contendedAcquire() { |
| debug_trace(); |
| |
| // To act as a mutex, we need an acquire barrier when we acquire the lock. |
| SK_POTENTIALLY_BLOCKING_REGION_BEGIN; |
| while (fLocked.exchange(true, std::memory_order_acquire)) { |
| do_pause(); |
| } |
| SK_POTENTIALLY_BLOCKING_REGION_END; |
| } |