ikan Uploader :
Directory : /home/ubuntu/node-v16.18.1/deps/v8/src/heap/
Upload File : |
| Current File : //home/ubuntu/node-v16.18.1/deps/v8/src/heap/collection-barrier.cc |
// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/heap/collection-barrier.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/time.h"
#include "src/common/globals.h"
#include "src/execution/isolate.h"
#include "src/handles/handles.h"
#include "src/heap/gc-tracer.h"
#include "src/heap/heap-inl.h"
#include "src/heap/heap.h"
#include "src/heap/local-heap.h"
#include "src/heap/parked-scope.h"
namespace v8 {
namespace internal {
bool CollectionBarrier::WasGCRequested() {
return collection_requested_.load();
}
void CollectionBarrier::RequestGC() {
base::MutexGuard guard(&mutex_);
bool was_already_requested = collection_requested_.exchange(true);
if (!was_already_requested) {
CHECK(!timer_.IsStarted());
timer_.Start();
}
}
class BackgroundCollectionInterruptTask : public CancelableTask {
public:
explicit BackgroundCollectionInterruptTask(Heap* heap)
: CancelableTask(heap->isolate()), heap_(heap) {}
~BackgroundCollectionInterruptTask() override = default;
BackgroundCollectionInterruptTask(const BackgroundCollectionInterruptTask&) =
delete;
BackgroundCollectionInterruptTask& operator=(
const BackgroundCollectionInterruptTask&) = delete;
private:
// v8::internal::CancelableTask overrides.
void RunInternal() override { heap_->CheckCollectionRequested(); }
Heap* heap_;
};
void CollectionBarrier::NotifyShutdownRequested() {
base::MutexGuard guard(&mutex_);
if (timer_.IsStarted()) timer_.Stop();
shutdown_requested_ = true;
cv_wakeup_.NotifyAll();
}
void CollectionBarrier::ResumeThreadsAwaitingCollection() {
base::MutexGuard guard(&mutex_);
collection_requested_.store(false);
block_for_collection_ = false;
cv_wakeup_.NotifyAll();
}
bool CollectionBarrier::AwaitCollectionBackground(LocalHeap* local_heap) {
bool first_thread;
{
// Update flag before parking this thread, this guarantees that the flag is
// set before the next GC.
base::MutexGuard guard(&mutex_);
if (shutdown_requested_) return false;
first_thread = !block_for_collection_;
block_for_collection_ = true;
CHECK(timer_.IsStarted());
}
// The first thread needs to activate the stack guard and post the task.
if (first_thread) ActivateStackGuardAndPostTask();
ParkedScope scope(local_heap);
base::MutexGuard guard(&mutex_);
while (block_for_collection_) {
if (shutdown_requested_) return false;
cv_wakeup_.Wait(&mutex_);
}
return true;
}
void CollectionBarrier::ActivateStackGuardAndPostTask() {
Isolate* isolate = heap_->isolate();
ExecutionAccess access(isolate);
isolate->stack_guard()->RequestGC();
V8::GetCurrentPlatform()
->GetForegroundTaskRunner(reinterpret_cast<v8::Isolate*>(isolate))
->PostTask(std::make_unique<BackgroundCollectionInterruptTask>(heap_));
}
void CollectionBarrier::StopTimeToCollectionTimer() {
if (collection_requested_.load()) {
base::MutexGuard guard(&mutex_);
// The first thread that requests the GC, starts the timer first and *then*
// parks itself. Since we are in a safepoint here, the timer is always
// initialized here already.
CHECK(timer_.IsStarted());
base::TimeDelta delta = timer_.Elapsed();
TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("v8.gc"),
"V8.GC.TimeToCollectionOnBackground",
TRACE_EVENT_SCOPE_THREAD, "duration",
delta.InMillisecondsF());
heap_->isolate()
->counters()
->gc_time_to_collection_on_background()
->AddTimedSample(delta);
timer_.Stop();
}
}
} // namespace internal
} // namespace v8
Kontol Shell Bypass