Activate memory reducer for small heaps in background tabs.

src/heap/memory-reducer.cc

 // 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"
@@ skipping 29 matching lines @@
                  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();
+      (heap->incremental_marking()->CanBeActivated() || optimize_for_memory);
   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;
@@ skipping 50 matching lines @@
   }
   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);
+void MemoryReducer::NotifyPossibleGarbage(const Event& event) {
+  DCHECK_EQ(kPossibleGarbage, 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);
+        DCHECK(event.type == kPossibleGarbage || 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:
+        case kPossibleGarbage:
           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);
@@ skipping 36 matching lines @@
   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