Revert of Replace reduce-memory mode in idle notification with delayed clean-up GC.

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/heap.h"
-#include "src/utils.h"
-#include "src/v8.h"
-
-namespace v8 {
-namespace internal {
-
-const int MemoryReducer::kLongDelayMs = 5000;
-const int MemoryReducer::kShortDelayMs = 500;
-const int MemoryReducer::kMaxNumberOfGCs = 3;
-
-
-void MemoryReducer::TimerTask::Run() {
-  Heap* heap = memory_reducer_->heap();
-  Event event;
-  event.type = kTimer;
-  event.time_ms = heap->MonotonicallyIncreasingTimeInMs();
-  event.low_allocation_rate = heap->HasLowAllocationRate();
-  event.can_start_incremental_gc =
-      heap->incremental_marking()->IsStopped() &&
-      heap->incremental_marking()->CanBeActivated();
-  memory_reducer_->NotifyTimer(event);
-}
-
-
-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);
-    heap()->StartIdleIncrementalMarking();
-    if (FLAG_trace_gc_verbose) {
-      PrintIsolate(heap()->isolate(), "Memory reducer: started GC #%d\n",
-                   state_.started_gcs);
-    }
-  } else if (state_.action == kWait) {
-    // Re-schedule the timer.
-    ScheduleTimer(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(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(state_.next_gc_start_ms - event.time_ms);
-  }
-}
-
-
-// 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) {
-    return State(kDone, 0, 0);
-  }
-  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);
-      }
-    case kWait:
-      if (event.type == kContextDisposed) {
-        return state;
-      } else if (event.type == kTimer && event.can_start_incremental_gc &&
-                 event.low_allocation_rate) {
-        if (state.next_gc_start_ms <= event.time_ms) {
-          return State(kRun, state.started_gcs + 1, 0.0);
-        } else {
-          return state;
-        }
-      } else {
-        return State(kWait, state.started_gcs, event.time_ms + kLongDelayMs);
-      }
-    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);
-        } else {
-          return State(kDone, 0, 0.0);
-        }
-      }
-  }
-  UNREACHABLE();
-  return State(kDone, 0, 0);  // Make the compiler happy.
-}
-
-
-void MemoryReducer::ScheduleTimer(double delay_ms) {
-  DCHECK(delay_ms > 0);
-  // Leave some room for precision error in task scheduler.
-  const double kSlackMs = 100;
-  v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(heap()->isolate());
-  V8::GetCurrentPlatform()->CallDelayedOnForegroundThread(
-      isolate, new MemoryReducer::TimerTask(this),
-      (delay_ms + kSlackMs) / 1000.0);
-}
-
-}  // internal
-}  // v8