[heap] Add a guard for restarting the memory reducer after mark-compact.

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"
 #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;
+const double MemoryReducer::kCommittedMemoryFactor = 1.1;
+const size_t MemoryReducer::kCommittedMemoryDelta = 10 * MB;
 
 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;
@@ skipping 11 matching lines @@
   }
   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() || optimize_for_memory);
+  event.committed_memory = heap->CommittedOldGenerationMemory();
   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 70 matching lines @@
 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);
+    return State(kDone, 0, 0, state.last_gc_time_ms, 0);
   }
   switch (state.action) {
     case kDone:
       if (event.type == kTimer) {
         return state;
+      } else if (event.type == kMarkCompact) {
+        if (event.committed_memory <
+            Max(static_cast<size_t>(state.committed_memory_at_last_run *
+                                    kCommittedMemoryFactor),
+                state.committed_memory_at_last_run + kCommittedMemoryDelta)) {
+          return state;
+        } else {
+          return State(kWait, 0, event.time_ms + kLongDelayMs,
+                       event.type == kMarkCompact ? event.time_ms
+                                                  : state.last_gc_time_ms,
+                       0);
+        }
       } else {
-        DCHECK(event.type == kPossibleGarbage || event.type == kMarkCompact);
+        DCHECK_EQ(kPossibleGarbage, event.type);
         return State(
             kWait, 0, event.time_ms + kLongDelayMs,
-            event.type == kMarkCompact ? event.time_ms : state.last_gc_time_ms);
+            event.type == kMarkCompact ? event.time_ms : state.last_gc_time_ms,
+            0);
       }
     case kWait:
       switch (event.type) {
         case kPossibleGarbage:
           return state;
         case kTimer:
           if (state.started_gcs >= kMaxNumberOfGCs) {
-            return State(kDone, kMaxNumberOfGCs, 0.0, state.last_gc_time_ms);
+            return State(kDone, kMaxNumberOfGCs, 0.0, state.last_gc_time_ms,
+                         event.committed_memory);
           } 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);
+                           state.last_gc_time_ms, 0);
             } else {
               return state;
             }
           } else {
             return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
-                         state.last_gc_time_ms);
+                         state.last_gc_time_ms, 0);
           }
         case kMarkCompact:
           return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs,
-                       event.time_ms);
+                       event.time_ms, 0);
       }
     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);
+                       event.time_ms, 0);
         } else {
-          return State(kDone, kMaxNumberOfGCs, 0.0, event.time_ms);
+          return State(kDone, kMaxNumberOfGCs, 0.0, event.time_ms,
+                       event.committed_memory);
         }
       }
   }
   UNREACHABLE();
-  return State(kDone, 0, 0, 0.0);  // Make the compiler happy.
+  return State(kDone, 0, 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); }
+void MemoryReducer::TearDown() { state_ = State(kDone, 0, 0, 0.0, 0); }
 
 }  // namespace internal
 }  // namespace v8