v8_platform.cc 16 KB

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  1. // Copyright 2014 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #include "gin/public/v8_platform.h"
  5. #include <algorithm>
  6. #include "base/bind.h"
  7. #include "base/bit_cast.h"
  8. #include "base/check_op.h"
  9. #include "base/debug/stack_trace.h"
  10. #include "base/location.h"
  11. #include "base/memory/nonscannable_memory.h"
  12. #include "base/memory/raw_ptr.h"
  13. #include "base/rand_util.h"
  14. #include "base/system/sys_info.h"
  15. #include "base/task/post_job.h"
  16. #include "base/task/task_traits.h"
  17. #include "base/task/thread_pool.h"
  18. #include "base/task/thread_pool/thread_pool_instance.h"
  19. #include "base/trace_event/trace_event.h"
  20. #include "base/tracing_buildflags.h"
  21. #include "build/build_config.h"
  22. #include "gin/per_isolate_data.h"
  23. #include "v8_platform_page_allocator.h"
  24. namespace gin {
  25. namespace {
  26. base::LazyInstance<V8Platform>::Leaky g_v8_platform = LAZY_INSTANCE_INITIALIZER;
  27. constexpr base::TaskTraits kLowPriorityTaskTraits = {
  28. base::TaskPriority::BEST_EFFORT};
  29. constexpr base::TaskTraits kDefaultTaskTraits = {
  30. base::TaskPriority::USER_VISIBLE};
  31. constexpr base::TaskTraits kBlockingTaskTraits = {
  32. base::TaskPriority::USER_BLOCKING};
  33. void PrintStackTrace() {
  34. base::debug::StackTrace trace;
  35. trace.Print();
  36. }
  37. class ConvertableToTraceFormatWrapper final
  38. : public base::trace_event::ConvertableToTraceFormat {
  39. public:
  40. explicit ConvertableToTraceFormatWrapper(
  41. std::unique_ptr<v8::ConvertableToTraceFormat> inner)
  42. : inner_(std::move(inner)) {}
  43. ConvertableToTraceFormatWrapper(const ConvertableToTraceFormatWrapper&) =
  44. delete;
  45. ConvertableToTraceFormatWrapper& operator=(
  46. const ConvertableToTraceFormatWrapper&) = delete;
  47. ~ConvertableToTraceFormatWrapper() override = default;
  48. void AppendAsTraceFormat(std::string* out) const final {
  49. inner_->AppendAsTraceFormat(out);
  50. }
  51. private:
  52. std::unique_ptr<v8::ConvertableToTraceFormat> inner_;
  53. };
  54. class EnabledStateObserverImpl final
  55. : public base::trace_event::TraceLog::EnabledStateObserver {
  56. public:
  57. EnabledStateObserverImpl() {
  58. base::trace_event::TraceLog::GetInstance()->AddEnabledStateObserver(this);
  59. }
  60. EnabledStateObserverImpl(const EnabledStateObserverImpl&) = delete;
  61. EnabledStateObserverImpl& operator=(const EnabledStateObserverImpl&) = delete;
  62. ~EnabledStateObserverImpl() override {
  63. base::trace_event::TraceLog::GetInstance()->RemoveEnabledStateObserver(
  64. this);
  65. }
  66. void OnTraceLogEnabled() final {
  67. base::AutoLock lock(mutex_);
  68. for (auto* o : observers_) {
  69. o->OnTraceEnabled();
  70. }
  71. }
  72. void OnTraceLogDisabled() final {
  73. base::AutoLock lock(mutex_);
  74. for (auto* o : observers_) {
  75. o->OnTraceDisabled();
  76. }
  77. }
  78. void AddObserver(v8::TracingController::TraceStateObserver* observer) {
  79. {
  80. base::AutoLock lock(mutex_);
  81. DCHECK(!observers_.count(observer));
  82. observers_.insert(observer);
  83. }
  84. // Fire the observer if recording is already in progress.
  85. if (base::trace_event::TraceLog::GetInstance()->IsEnabled())
  86. observer->OnTraceEnabled();
  87. }
  88. void RemoveObserver(v8::TracingController::TraceStateObserver* observer) {
  89. base::AutoLock lock(mutex_);
  90. DCHECK(observers_.count(observer) == 1);
  91. observers_.erase(observer);
  92. }
  93. private:
  94. base::Lock mutex_;
  95. std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
  96. };
  97. base::LazyInstance<EnabledStateObserverImpl>::Leaky g_trace_state_dispatcher =
  98. LAZY_INSTANCE_INITIALIZER;
  99. // TODO(skyostil): Deduplicate this with the clamper in Blink.
  100. class TimeClamper {
  101. public:
  102. // As site isolation is enabled on desktop platforms, we can safely provide
  103. // more timing resolution. Jittering is still enabled everywhere.
  104. #if BUILDFLAG(IS_ANDROID)
  105. static constexpr double kResolutionSeconds = 100e-6;
  106. #else
  107. static constexpr double kResolutionSeconds = 5e-6;
  108. #endif
  109. TimeClamper() : secret_(base::RandUint64()) {}
  110. TimeClamper(const TimeClamper&) = delete;
  111. TimeClamper& operator=(const TimeClamper&) = delete;
  112. double ClampTimeResolution(double time_seconds) const {
  113. bool was_negative = false;
  114. if (time_seconds < 0) {
  115. was_negative = true;
  116. time_seconds = -time_seconds;
  117. }
  118. // For each clamped time interval, compute a pseudorandom transition
  119. // threshold. The reported time will either be the start of that interval or
  120. // the next one depending on which side of the threshold |time_seconds| is.
  121. double interval = floor(time_seconds / kResolutionSeconds);
  122. double clamped_time = interval * kResolutionSeconds;
  123. double tick_threshold = ThresholdFor(clamped_time);
  124. if (time_seconds >= tick_threshold)
  125. clamped_time = (interval + 1) * kResolutionSeconds;
  126. if (was_negative)
  127. clamped_time = -clamped_time;
  128. return clamped_time;
  129. }
  130. private:
  131. inline double ThresholdFor(double clamped_time) const {
  132. uint64_t time_hash =
  133. MurmurHash3(base::bit_cast<int64_t>(clamped_time) ^ secret_);
  134. return clamped_time + kResolutionSeconds * ToDouble(time_hash);
  135. }
  136. static inline double ToDouble(uint64_t value) {
  137. // Exponent for double values for [1.0 .. 2.0]
  138. static const uint64_t kExponentBits = uint64_t{0x3FF0000000000000};
  139. static const uint64_t kMantissaMask = uint64_t{0x000FFFFFFFFFFFFF};
  140. uint64_t random = (value & kMantissaMask) | kExponentBits;
  141. return base::bit_cast<double>(random) - 1;
  142. }
  143. static inline uint64_t MurmurHash3(uint64_t value) {
  144. value ^= value >> 33;
  145. value *= uint64_t{0xFF51AFD7ED558CCD};
  146. value ^= value >> 33;
  147. value *= uint64_t{0xC4CEB9FE1A85EC53};
  148. value ^= value >> 33;
  149. return value;
  150. }
  151. const uint64_t secret_;
  152. };
  153. base::LazyInstance<TimeClamper>::Leaky g_time_clamper =
  154. LAZY_INSTANCE_INITIALIZER;
  155. #if BUILDFLAG(USE_PARTITION_ALLOC)
  156. base::LazyInstance<gin::PageAllocator>::Leaky g_page_allocator =
  157. LAZY_INSTANCE_INITIALIZER;
  158. #endif // BUILDFLAG(USE_PARTITION_ALLOC)
  159. class JobDelegateImpl : public v8::JobDelegate {
  160. public:
  161. explicit JobDelegateImpl(base::JobDelegate* delegate) : delegate_(delegate) {}
  162. JobDelegateImpl() = default;
  163. JobDelegateImpl(const JobDelegateImpl&) = delete;
  164. JobDelegateImpl& operator=(const JobDelegateImpl&) = delete;
  165. // v8::JobDelegate:
  166. bool ShouldYield() override { return delegate_->ShouldYield(); }
  167. void NotifyConcurrencyIncrease() override {
  168. delegate_->NotifyConcurrencyIncrease();
  169. }
  170. uint8_t GetTaskId() override { return delegate_->GetTaskId(); }
  171. bool IsJoiningThread() const override { return delegate_->IsJoiningThread(); }
  172. private:
  173. raw_ptr<base::JobDelegate> delegate_;
  174. };
  175. class JobHandleImpl : public v8::JobHandle {
  176. public:
  177. explicit JobHandleImpl(base::JobHandle handle) : handle_(std::move(handle)) {}
  178. ~JobHandleImpl() override = default;
  179. JobHandleImpl(const JobHandleImpl&) = delete;
  180. JobHandleImpl& operator=(const JobHandleImpl&) = delete;
  181. // v8::JobHandle:
  182. void NotifyConcurrencyIncrease() override {
  183. handle_.NotifyConcurrencyIncrease();
  184. }
  185. bool UpdatePriorityEnabled() const override { return true; }
  186. void UpdatePriority(v8::TaskPriority new_priority) override {
  187. handle_.UpdatePriority(ToBaseTaskPriority(new_priority));
  188. }
  189. void Join() override { handle_.Join(); }
  190. void Cancel() override { handle_.Cancel(); }
  191. void CancelAndDetach() override { handle_.CancelAndDetach(); }
  192. bool IsActive() override { return handle_.IsActive(); }
  193. bool IsValid() override { return !!handle_; }
  194. private:
  195. static base::TaskPriority ToBaseTaskPriority(v8::TaskPriority priority) {
  196. switch (priority) {
  197. case v8::TaskPriority::kBestEffort:
  198. return base::TaskPriority::BEST_EFFORT;
  199. case v8::TaskPriority::kUserVisible:
  200. return base::TaskPriority::USER_VISIBLE;
  201. case v8::TaskPriority::kUserBlocking:
  202. return base::TaskPriority::USER_BLOCKING;
  203. }
  204. }
  205. base::JobHandle handle_;
  206. };
  207. } // namespace
  208. } // namespace gin
  209. // Allow std::unique_ptr<v8::ConvertableToTraceFormat> to be a valid
  210. // initialization value for trace macros.
  211. template <>
  212. struct base::trace_event::TraceValue::Helper<
  213. std::unique_ptr<v8::ConvertableToTraceFormat>> {
  214. static constexpr unsigned char kType = TRACE_VALUE_TYPE_CONVERTABLE;
  215. static inline void SetValue(
  216. TraceValue* v,
  217. std::unique_ptr<v8::ConvertableToTraceFormat> value) {
  218. // NOTE: |as_convertable| is an owning pointer, so using new here
  219. // is acceptable.
  220. v->as_convertable =
  221. new gin::ConvertableToTraceFormatWrapper(std::move(value));
  222. }
  223. };
  224. namespace gin {
  225. class V8Platform::TracingControllerImpl : public v8::TracingController {
  226. public:
  227. TracingControllerImpl() = default;
  228. TracingControllerImpl(const TracingControllerImpl&) = delete;
  229. TracingControllerImpl& operator=(const TracingControllerImpl&) = delete;
  230. ~TracingControllerImpl() override = default;
  231. // TracingController implementation.
  232. #if !BUILDFLAG(USE_PERFETTO_CLIENT_LIBRARY)
  233. const uint8_t* GetCategoryGroupEnabled(const char* name) override {
  234. return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(name);
  235. }
  236. uint64_t AddTraceEvent(
  237. char phase,
  238. const uint8_t* category_enabled_flag,
  239. const char* name,
  240. const char* scope,
  241. uint64_t id,
  242. uint64_t bind_id,
  243. int32_t num_args,
  244. const char** arg_names,
  245. const uint8_t* arg_types,
  246. const uint64_t* arg_values,
  247. std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
  248. unsigned int flags) override {
  249. base::trace_event::TraceArguments args(
  250. num_args, arg_names, arg_types,
  251. reinterpret_cast<const unsigned long long*>(arg_values),
  252. arg_convertables);
  253. DCHECK_LE(num_args, 2);
  254. base::trace_event::TraceEventHandle handle =
  255. TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_BIND_ID(
  256. phase, category_enabled_flag, name, scope, id, bind_id, &args,
  257. flags);
  258. uint64_t result;
  259. memcpy(&result, &handle, sizeof(result));
  260. return result;
  261. }
  262. uint64_t AddTraceEventWithTimestamp(
  263. char phase,
  264. const uint8_t* category_enabled_flag,
  265. const char* name,
  266. const char* scope,
  267. uint64_t id,
  268. uint64_t bind_id,
  269. int32_t num_args,
  270. const char** arg_names,
  271. const uint8_t* arg_types,
  272. const uint64_t* arg_values,
  273. std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
  274. unsigned int flags,
  275. int64_t timestampMicroseconds) override {
  276. base::trace_event::TraceArguments args(
  277. num_args, arg_names, arg_types,
  278. reinterpret_cast<const unsigned long long*>(arg_values),
  279. arg_convertables);
  280. DCHECK_LE(num_args, 2);
  281. base::TimeTicks timestamp =
  282. base::TimeTicks() + base::Microseconds(timestampMicroseconds);
  283. base::trace_event::TraceEventHandle handle =
  284. TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
  285. phase, category_enabled_flag, name, scope, id, bind_id,
  286. TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, &args, flags);
  287. uint64_t result;
  288. memcpy(&result, &handle, sizeof(result));
  289. return result;
  290. }
  291. void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
  292. const char* name,
  293. uint64_t handle) override {
  294. base::trace_event::TraceEventHandle traceEventHandle;
  295. memcpy(&traceEventHandle, &handle, sizeof(handle));
  296. TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_enabled_flag, name,
  297. traceEventHandle);
  298. }
  299. #endif // !BUILDFLAG(USE_PERFETTO_CLIENT_LIBRARY)
  300. void AddTraceStateObserver(TraceStateObserver* observer) override {
  301. g_trace_state_dispatcher.Get().AddObserver(observer);
  302. }
  303. void RemoveTraceStateObserver(TraceStateObserver* observer) override {
  304. g_trace_state_dispatcher.Get().RemoveObserver(observer);
  305. }
  306. };
  307. // static
  308. V8Platform* V8Platform::Get() { return g_v8_platform.Pointer(); }
  309. V8Platform::V8Platform() : tracing_controller_(new TracingControllerImpl) {}
  310. V8Platform::~V8Platform() = default;
  311. #if BUILDFLAG(USE_PARTITION_ALLOC)
  312. PageAllocator* V8Platform::GetPageAllocator() {
  313. return g_page_allocator.Pointer();
  314. }
  315. void V8Platform::OnCriticalMemoryPressure() {
  316. // We only have a reservation on 32-bit Windows systems.
  317. // TODO(bbudge) Make the #if's in BlinkInitializer match.
  318. #if BUILDFLAG(IS_WIN) && defined(ARCH_CPU_32_BITS)
  319. partition_alloc::ReleaseReservation();
  320. #endif
  321. }
  322. v8::ZoneBackingAllocator* V8Platform::GetZoneBackingAllocator() {
  323. static struct Allocator final : v8::ZoneBackingAllocator {
  324. MallocFn GetMallocFn() const override {
  325. return &base::AllocNonQuarantinable;
  326. }
  327. FreeFn GetFreeFn() const override { return &base::FreeNonQuarantinable; }
  328. } allocator;
  329. return &allocator;
  330. }
  331. #endif // BUILDFLAG(USE_PARTITION_ALLOC)
  332. std::shared_ptr<v8::TaskRunner> V8Platform::GetForegroundTaskRunner(
  333. v8::Isolate* isolate) {
  334. PerIsolateData* data = PerIsolateData::From(isolate);
  335. return data->task_runner();
  336. }
  337. int V8Platform::NumberOfWorkerThreads() {
  338. // V8Platform assumes the scheduler uses the same set of workers for default
  339. // and user blocking tasks.
  340. const size_t num_foreground_workers =
  341. base::ThreadPoolInstance::Get()
  342. ->GetMaxConcurrentNonBlockedTasksWithTraitsDeprecated(
  343. kDefaultTaskTraits);
  344. DCHECK_EQ(num_foreground_workers,
  345. base::ThreadPoolInstance::Get()
  346. ->GetMaxConcurrentNonBlockedTasksWithTraitsDeprecated(
  347. kBlockingTaskTraits));
  348. return std::max(1, static_cast<int>(num_foreground_workers));
  349. }
  350. void V8Platform::CallOnWorkerThread(std::unique_ptr<v8::Task> task) {
  351. base::ThreadPool::PostTask(FROM_HERE, kDefaultTaskTraits,
  352. base::BindOnce(&v8::Task::Run, std::move(task)));
  353. }
  354. void V8Platform::CallBlockingTaskOnWorkerThread(
  355. std::unique_ptr<v8::Task> task) {
  356. base::ThreadPool::PostTask(FROM_HERE, kBlockingTaskTraits,
  357. base::BindOnce(&v8::Task::Run, std::move(task)));
  358. }
  359. void V8Platform::CallLowPriorityTaskOnWorkerThread(
  360. std::unique_ptr<v8::Task> task) {
  361. base::ThreadPool::PostTask(FROM_HERE, kLowPriorityTaskTraits,
  362. base::BindOnce(&v8::Task::Run, std::move(task)));
  363. }
  364. void V8Platform::CallDelayedOnWorkerThread(std::unique_ptr<v8::Task> task,
  365. double delay_in_seconds) {
  366. base::ThreadPool::PostDelayedTask(
  367. FROM_HERE, kDefaultTaskTraits,
  368. base::BindOnce(&v8::Task::Run, std::move(task)),
  369. base::Seconds(delay_in_seconds));
  370. }
  371. std::unique_ptr<v8::JobHandle> V8Platform::CreateJob(
  372. v8::TaskPriority priority,
  373. std::unique_ptr<v8::JobTask> job_task) {
  374. base::TaskTraits task_traits;
  375. switch (priority) {
  376. case v8::TaskPriority::kBestEffort:
  377. task_traits = kLowPriorityTaskTraits;
  378. break;
  379. case v8::TaskPriority::kUserVisible:
  380. task_traits = kDefaultTaskTraits;
  381. break;
  382. case v8::TaskPriority::kUserBlocking:
  383. task_traits = kBlockingTaskTraits;
  384. break;
  385. }
  386. // Ownership of |job_task| is assumed by |worker_task|, while
  387. // |max_concurrency_callback| uses an unretained pointer.
  388. auto* job_task_ptr = job_task.get();
  389. auto handle =
  390. base::CreateJob(FROM_HERE, task_traits,
  391. base::BindRepeating(
  392. [](const std::unique_ptr<v8::JobTask>& job_task,
  393. base::JobDelegate* delegate) {
  394. JobDelegateImpl delegate_impl(delegate);
  395. job_task->Run(&delegate_impl);
  396. },
  397. std::move(job_task)),
  398. base::BindRepeating(
  399. [](v8::JobTask* job_task, size_t worker_count) {
  400. return job_task->GetMaxConcurrency(worker_count);
  401. },
  402. base::Unretained(job_task_ptr)));
  403. return std::make_unique<JobHandleImpl>(std::move(handle));
  404. }
  405. bool V8Platform::IdleTasksEnabled(v8::Isolate* isolate) {
  406. return PerIsolateData::From(isolate)->task_runner()->IdleTasksEnabled();
  407. }
  408. double V8Platform::MonotonicallyIncreasingTime() {
  409. return base::TimeTicks::Now().ToInternalValue() /
  410. static_cast<double>(base::Time::kMicrosecondsPerSecond);
  411. }
  412. double V8Platform::CurrentClockTimeMillis() {
  413. double now_seconds = base::Time::Now().ToJsTime() / 1000;
  414. return g_time_clamper.Get().ClampTimeResolution(now_seconds) * 1000;
  415. }
  416. v8::TracingController* V8Platform::GetTracingController() {
  417. return tracing_controller_.get();
  418. }
  419. v8::Platform::StackTracePrinter V8Platform::GetStackTracePrinter() {
  420. return PrintStackTrace;
  421. }
  422. } // namespace gin