Upgrade V8 to version 4.9.385.28
https://chromium.googlesource.com/v8/v8/+/4.9.385.28
FPIIM-449
Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/heap/memory-reducer.cc b/src/heap/memory-reducer.cc
new file mode 100644
index 0000000..ee10091
--- /dev/null
+++ b/src/heap/memory-reducer.cc
@@ -0,0 +1,213 @@
+// Copyright 2015 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/memory-reducer.h"
+
+#include "src/flags.h"
+#include "src/heap/gc-tracer.h"
+#include "src/heap/heap-inl.h"
+#include "src/utils.h"
+#include "src/v8.h"
+
+namespace v8 {
+namespace internal {
+
+const int MemoryReducer::kLongDelayMs = 8000;
+const int MemoryReducer::kShortDelayMs = 500;
+const int MemoryReducer::kWatchdogDelayMs = 100000;
+const int MemoryReducer::kMaxNumberOfGCs = 3;
+
+MemoryReducer::TimerTask::TimerTask(MemoryReducer* memory_reducer)
+ : CancelableTask(memory_reducer->heap()->isolate()),
+ memory_reducer_(memory_reducer) {}
+
+
+void MemoryReducer::TimerTask::RunInternal() {
+ const double kJsCallsPerMsThreshold = 0.5;
+ Heap* heap = memory_reducer_->heap();
+ Event event;
+ double time_ms = heap->MonotonicallyIncreasingTimeInMs();
+ heap->tracer()->SampleAllocation(time_ms, heap->NewSpaceAllocationCounter(),
+ heap->OldGenerationAllocationCounter());
+ double js_call_rate = memory_reducer_->SampleAndGetJsCallsPerMs(time_ms);
+ bool low_allocation_rate = heap->HasLowAllocationRate();
+ bool is_idle = js_call_rate < kJsCallsPerMsThreshold && low_allocation_rate;
+ bool optimize_for_memory = heap->ShouldOptimizeForMemoryUsage();
+ if (FLAG_trace_gc_verbose) {
+ PrintIsolate(heap->isolate(), "Memory reducer: call rate %.3lf, %s, %s\n",
+ js_call_rate, low_allocation_rate ? "low alloc" : "high alloc",
+ optimize_for_memory ? "background" : "foreground");
+ }
+ event.type = kTimer;
+ event.time_ms = time_ms;
+ // The memory reducer will start incremental markig if
+ // 1) mutator is likely idle: js call rate is low and allocation rate is low.
+ // 2) mutator is in background: optimize for memory flag is set.
+ event.should_start_incremental_gc = is_idle || optimize_for_memory;
+ event.can_start_incremental_gc =
+ heap->incremental_marking()->IsStopped() &&
+ heap->incremental_marking()->CanBeActivated();
+ memory_reducer_->NotifyTimer(event);
+}
+
+
+double MemoryReducer::SampleAndGetJsCallsPerMs(double time_ms) {
+ unsigned int counter = heap()->isolate()->js_calls_from_api_counter();
+ unsigned int call_delta = counter - js_calls_counter_;
+ double time_delta_ms = time_ms - js_calls_sample_time_ms_;
+ js_calls_counter_ = counter;
+ js_calls_sample_time_ms_ = time_ms;
+ return time_delta_ms > 0 ? call_delta / time_delta_ms : 0;
+}
+
+
+void MemoryReducer::NotifyTimer(const Event& event) {
+ DCHECK_EQ(kTimer, event.type);
+ DCHECK_EQ(kWait, state_.action);
+ state_ = Step(state_, event);
+ if (state_.action == kRun) {
+ DCHECK(heap()->incremental_marking()->IsStopped());
+ DCHECK(FLAG_incremental_marking);
+ if (FLAG_trace_gc_verbose) {
+ PrintIsolate(heap()->isolate(), "Memory reducer: started GC #%d\n",
+ state_.started_gcs);
+ }
+ heap()->StartIdleIncrementalMarking();
+ } else if (state_.action == kWait) {
+ if (!heap()->incremental_marking()->IsStopped() &&
+ heap()->ShouldOptimizeForMemoryUsage()) {
+ // Make progress with pending incremental marking if memory usage has
+ // higher priority than latency. This is important for background tabs
+ // that do not send idle notifications.
+ const int kIncrementalMarkingDelayMs = 500;
+ double deadline = heap()->MonotonicallyIncreasingTimeInMs() +
+ kIncrementalMarkingDelayMs;
+ heap()->incremental_marking()->AdvanceIncrementalMarking(
+ 0, deadline, i::IncrementalMarking::StepActions(
+ i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
+ i::IncrementalMarking::FORCE_MARKING,
+ i::IncrementalMarking::FORCE_COMPLETION));
+ heap()->FinalizeIncrementalMarkingIfComplete(
+ "Memory reducer: finalize incremental marking");
+ }
+ // Re-schedule the timer.
+ ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
+ if (FLAG_trace_gc_verbose) {
+ PrintIsolate(heap()->isolate(), "Memory reducer: waiting for %.f ms\n",
+ state_.next_gc_start_ms - event.time_ms);
+ }
+ }
+}
+
+
+void MemoryReducer::NotifyMarkCompact(const Event& event) {
+ DCHECK_EQ(kMarkCompact, event.type);
+ Action old_action = state_.action;
+ state_ = Step(state_, event);
+ if (old_action != kWait && state_.action == kWait) {
+ // If we are transitioning to the WAIT state, start the timer.
+ ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
+ }
+ if (old_action == kRun) {
+ if (FLAG_trace_gc_verbose) {
+ PrintIsolate(heap()->isolate(), "Memory reducer: finished GC #%d (%s)\n",
+ state_.started_gcs,
+ state_.action == kWait ? "will do more" : "done");
+ }
+ }
+}
+
+
+void MemoryReducer::NotifyContextDisposed(const Event& event) {
+ DCHECK_EQ(kContextDisposed, event.type);
+ Action old_action = state_.action;
+ state_ = Step(state_, event);
+ if (old_action != kWait && state_.action == kWait) {
+ // If we are transitioning to the WAIT state, start the timer.
+ ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
+ }
+}
+
+
+bool MemoryReducer::WatchdogGC(const State& state, const Event& event) {
+ return state.last_gc_time_ms != 0 &&
+ event.time_ms > state.last_gc_time_ms + kWatchdogDelayMs;
+}
+
+
+// For specification of this function see the comment for MemoryReducer class.
+MemoryReducer::State MemoryReducer::Step(const State& state,
+ const Event& event) {
+ if (!FLAG_incremental_marking || !FLAG_memory_reducer) {
+ return State(kDone, 0, 0, state.last_gc_time_ms);
+ }
+ switch (state.action) {
+ case kDone:
+ if (event.type == kTimer) {
+ return state;
+ } else {
+ DCHECK(event.type == kContextDisposed || event.type == kMarkCompact);
+ return State(
+ kWait, 0, event.time_ms + kLongDelayMs,
+ event.type == kMarkCompact ? event.time_ms : state.last_gc_time_ms);
+ }
+ case kWait:
+ switch (event.type) {
+ case kContextDisposed:
+ return state;
+ case kTimer:
+ if (state.started_gcs >= kMaxNumberOfGCs) {
+ return State(kDone, kMaxNumberOfGCs, 0.0, state.last_gc_time_ms);
+ } else if (event.can_start_incremental_gc &&
+ (event.should_start_incremental_gc ||
+ WatchdogGC(state, event))) {
+ if (state.next_gc_start_ms <= event.time_ms) {
+ return State(kRun, state.started_gcs + 1, 0.0,
+ state.last_gc_time_ms);
+ } else {
+ return state;
+ }
+ } else {
+ return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
+ state.last_gc_time_ms);
+ }
+ case kMarkCompact:
+ return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
+ event.time_ms);
+ }
+ case kRun:
+ if (event.type != kMarkCompact) {
+ return state;
+ } else {
+ if (state.started_gcs < kMaxNumberOfGCs &&
+ (event.next_gc_likely_to_collect_more || state.started_gcs == 1)) {
+ return State(kWait, state.started_gcs, event.time_ms + kShortDelayMs,
+ event.time_ms);
+ } else {
+ return State(kDone, kMaxNumberOfGCs, 0.0, event.time_ms);
+ }
+ }
+ }
+ UNREACHABLE();
+ return State(kDone, 0, 0, 0.0); // Make the compiler happy.
+}
+
+
+void MemoryReducer::ScheduleTimer(double time_ms, double delay_ms) {
+ DCHECK(delay_ms > 0);
+ // Record the time and the js call counter.
+ SampleAndGetJsCallsPerMs(time_ms);
+ // Leave some room for precision error in task scheduler.
+ const double kSlackMs = 100;
+ v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(heap()->isolate());
+ auto timer_task = new MemoryReducer::TimerTask(this);
+ V8::GetCurrentPlatform()->CallDelayedOnForegroundThread(
+ isolate, timer_task, (delay_ms + kSlackMs) / 1000.0);
+}
+
+
+void MemoryReducer::TearDown() { state_ = State(kDone, 0, 0, 0.0); }
+
+} // namespace internal
+} // namespace v8