blob: c306d79249709081297d1a278017a6aff50ac2fa [file] [log] [blame]
/*
* Copyright (C) 2019 The Android Open Source Project
*
* 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.
*/
#include "src/profiling/memory/scoped_spinlock.h"
#include <unistd.h>
#include <atomic>
#include "perfetto/ext/base/utils.h"
namespace {
// Wait for ~1s before timing out (+- spurious wakeups from the sleeps).
constexpr unsigned kSleepAttempts = 1000;
constexpr unsigned kLockAttemptsPerSleep = 1000;
constexpr unsigned kSleepDurationUs = 1000;
} // namespace
namespace perfetto {
namespace profiling {
void ScopedSpinlock::LockSlow(Mode mode) {
for (size_t attempt = 0; mode == Mode::Blocking ||
attempt < kLockAttemptsPerSleep * kSleepAttempts;
attempt++) {
if (!lock_->load(std::memory_order_relaxed) &&
PERFETTO_LIKELY(!lock_->exchange(true, std::memory_order_acquire))) {
locked_ = true;
return;
}
if (attempt && attempt % kLockAttemptsPerSleep == 0)
usleep(kSleepDurationUs);
}
}
} // namespace profiling
} // namespace perfetto