blob: 309ecc47f8277f48063d5bdbfdcc56a4f2bfd67c [file] [log] [blame]
// Copyright 2016 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 <cstdint>
#include <memory>
#include <unordered_set>
#include <utility>
#include <vector>
#include "src/base/atomic-utils.h"
#include "src/base/macros.h"
#include "src/base/platform/condition-variable.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/semaphore.h"
#include "src/common/globals.h"
#include "src/utils/identity-map.h"
#include "testing/gtest/include/gtest/gtest_prod.h" // nogncheck
namespace v8 {
class JobDelegate;
class JobHandle;
class Platform;
class TaskRunner;
enum class MemoryPressureLevel;
namespace internal {
class AstRawString;
class AstValueFactory;
class BackgroundCompileTask;
class CancelableTaskManager;
class UnoptimizedCompileJob;
class UnoptimizedCompileState;
class FunctionLiteral;
class ParseInfo;
class ProducedPreparseData;
class SharedFunctionInfo;
class TimedHistogram;
class Utf16CharacterStream;
class WorkerThreadRuntimeCallStats;
class Zone;
// The LazyCompileDispatcher uses a combination of idle tasks and background
// tasks to parse and compile lazily parsed functions.
// As both parsing and compilation currently requires a preparation and
// finalization step that happens on the main thread, every task has to be
// advanced during idle time first. Depending on the properties of the task, it
// can then be parsed or compiled on either background threads, or during idle
// time. Last, it has to be finalized during idle time again.
// LazyCompileDispatcher::jobs_ maintains the list of all
// LazyCompilerDispatcherJobs the LazyCompileDispatcher knows about.
// LazyCompileDispatcher::pending_background_jobs_ contains the set of
// LazyCompilerDispatcherJobs that can be processed on a background thread.
// LazyCompileDispatcher::running_background_jobs_ contains the set of
// LazyCompilerDispatcherJobs that are currently being processed on a background
// thread.
// LazyCompileDispatcher::DoIdleWork tries to advance as many jobs out of jobs_
// as possible during idle time. If a job can't be advanced, but is suitable for
// background processing, it fires off background threads.
// LazyCompileDispatcher::DoBackgroundWork advances one of the pending jobs,
// and then spins of another idle task to potentially do the final step on the
// main thread.
class V8_EXPORT_PRIVATE LazyCompileDispatcher {
using JobId = uintptr_t;
LazyCompileDispatcher(Isolate* isolate, Platform* platform,
size_t max_stack_size);
LazyCompileDispatcher(const LazyCompileDispatcher&) = delete;
LazyCompileDispatcher& operator=(const LazyCompileDispatcher&) = delete;
void Enqueue(LocalIsolate* isolate, Handle<SharedFunctionInfo> shared_info,
std::unique_ptr<Utf16CharacterStream> character_stream);
// Returns true if there is a pending job registered for the given function.
bool IsEnqueued(Handle<SharedFunctionInfo> function) const;
// Blocks until the given function is compiled (and does so as fast as
// possible). Returns true if the compile job was successful.
bool FinishNow(Handle<SharedFunctionInfo> function);
// Aborts compilation job for the given function.
void AbortJob(Handle<SharedFunctionInfo> function);
// Aborts all jobs, blocking until all jobs are aborted.
void AbortAll();
FRIEND_TEST(LazyCompileDispatcherTest, IdleTaskNoIdleTime);
FRIEND_TEST(LazyCompileDispatcherTest, IdleTaskSmallIdleTime);
FRIEND_TEST(LazyCompileDispatcherTest, FinishNowWithWorkerTask);
FRIEND_TEST(LazyCompileDispatcherTest, AbortJobNotStarted);
FRIEND_TEST(LazyCompileDispatcherTest, AbortJobAlreadyStarted);
FRIEND_TEST(LazyCompileDispatcherTest, AsyncAbortAllPendingWorkerTask);
FRIEND_TEST(LazyCompileDispatcherTest, AsyncAbortAllRunningWorkerTask);
FRIEND_TEST(LazyCompileDispatcherTest, CompileMultipleOnBackgroundThread);
// JobTask for PostJob API.
class JobTask;
struct Job {
enum class State {
// Background thread states (Enqueue + DoBackgroundWork)
// ---
// In the pending task queue.
// Currently running on a background thread.
kAbortRequested, // ... but we want to drop the result.
// In the finalizable task queue.
// Main thread states (FinishNow and FinalizeSingleJob)
// ---
// Popped off the pending task queue.
// Popped off the finalizable task queue.
kAbortingNow, // ... and we want to abort
// Finished finalizing, ready for deletion.
explicit Job(std::unique_ptr<BackgroundCompileTask> task);
bool is_running_on_background() const {
return state == State::kRunning || state == State::kAbortRequested;
std::unique_ptr<BackgroundCompileTask> task;
State state = State::kPending;
using SharedToJobMap = IdentityMap<Job*, FreeStoreAllocationPolicy>;
void WaitForJobIfRunningOnBackground(Job* job, const base::MutexGuard&);
Job* GetJobFor(Handle<SharedFunctionInfo> shared,
const base::MutexGuard&) const;
Job* PopSingleFinalizeJob();
void ScheduleIdleTaskFromAnyThread(const base::MutexGuard&);
bool FinalizeSingleJob();
void DoBackgroundWork(JobDelegate* delegate);
void DoIdleWork(double deadline_in_seconds);
// DeleteJob without the mutex held.
void DeleteJob(Job* job);
// DeleteJob with the mutex already held.
void DeleteJob(Job* job, const base::MutexGuard&);
void NotifyAddedBackgroundJob(const base::MutexGuard& lock) {
void NotifyRemovedBackgroundJob(const base::MutexGuard& lock) {
#ifdef DEBUG
void VerifyBackgroundTaskCount(const base::MutexGuard&);
void VerifyBackgroundTaskCount(const base::MutexGuard&) {}
Isolate* isolate_;
WorkerThreadRuntimeCallStats* worker_thread_runtime_call_stats_;
TimedHistogram* background_compile_timer_;
std::shared_ptr<TaskRunner> taskrunner_;
Platform* platform_;
size_t max_stack_size_;
std::unique_ptr<JobHandle> job_handle_;
// Copy of v8_flags.trace_compiler_dispatcher to allow for access from any
// thread.
bool trace_compiler_dispatcher_;
std::unique_ptr<CancelableTaskManager> idle_task_manager_;
// The following members can be accessed from any thread. Methods need to hold
// the mutex |mutex_| while accessing them.
mutable base::Mutex mutex_;
// True if an idle task is scheduled to be run.
bool idle_task_scheduled_;
// The set of jobs that can be run on a background thread.
std::vector<Job*> pending_background_jobs_;
// The set of jobs that can be finalized on the main thread.
std::vector<Job*> finalizable_jobs_;
// The total number of jobs ready to execute on background, both those pending
// and those currently running.
std::atomic<size_t> num_jobs_for_background_;
#ifdef DEBUG
// The set of all allocated jobs, used for verification of the various queues
// and counts.
std::unordered_set<Job*> all_jobs_;
// A queue of jobs to delete on the background thread(s). Jobs in this queue
// are considered dead as far as the rest of the system is concerned, so they
// won't be pointed to by any SharedFunctionInfo and won't be in the all_jobs
// set above.
std::vector<Job*> jobs_to_dispose_;
// If not nullptr, then the main thread waits for the task processing
// this job, and blocks on the ConditionVariable main_thread_blocking_signal_.
Job* main_thread_blocking_on_job_;
base::ConditionVariable main_thread_blocking_signal_;
// Test support.
base::AtomicValue<bool> block_for_testing_;
base::Semaphore semaphore_for_testing_;
} // namespace internal
} // namespace v8