base: Add soft memory limit to DiscardableMemoryManager.

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 The Chromium 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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 935 matching lines @@
 
   base::allocator::ReleaseFreeMemory();
 
   // Continue the idle timer if the webkit shared timer is not suspended or
   // something is left to do.
   bool continue_timer = !webkit_shared_timer_suspended_;
 
   if (!v8::V8::IdleNotification()) {
     continue_timer = true;
   }
+  if (!base::DiscardableMemory::ReduceMemoryUsage()) {
+    continue_timer = true;
+  }
 
   // Schedule next invocation.
   // Dampen the delay using the algorithm (if delay is in seconds):
   //    delay = delay + 1 / (delay + 2)
   // Using floor(delay) has a dampening effect such as:
   //    1s, 1, 1, 2, 2, 2, 2, 3, 3, ...
   // If the delay is in milliseconds, the above formula is equivalent to:
   //    delay_ms / 1000 = delay_ms / 1000 + 1 / (delay_ms / 1000 + 2)
   // which is equivalent to
   //    delay_ms = delay_ms + 1000*1000 / (delay_ms + 2000).
@@ skipping 21 matching lines @@
   if (idle_notifications_to_skip_ > 0) {
     idle_notifications_to_skip_--;
   } else  {
     int cpu_usage = 0;
     Send(new ViewHostMsg_GetCPUUsage(&cpu_usage));
     // Idle notification hint roughly specifies the expected duration of the
     // idle pause. We set it proportional to the idle timer delay.
     int idle_hint = static_cast<int>(new_delay_ms / 10);
     if (cpu_usage < kIdleCPUUsageThresholdInPercents) {
       base::allocator::ReleaseFreeMemory();
-      if (v8::V8::IdleNotification(idle_hint)) {
-        // V8 finished collecting garbage.
+
+      bool finished_idle_work = true;
+      if (!v8::V8::IdleNotification(idle_hint))
+        finished_idle_work = false;
+      if (!base::DiscardableMemory::ReduceMemoryUsage())
+        finished_idle_work = false;
+
+      // V8 finished collecting garbage and discardable memory system has no
+      // more idle work left.
+      if (finished_idle_work)
         new_delay_ms = kLongIdleHandlerDelayMs;
-      }
     }
   }
   ScheduleIdleHandler(new_delay_ms);
 }
 
 int64 RenderThreadImpl::GetIdleNotificationDelayInMs() const {
   return idle_notification_delay_in_ms_;
 }
 
 void RenderThreadImpl::SetIdleNotificationDelayInMs(
@@ skipping 554 matching lines @@
   hidden_widget_count_--;
 
   if (!GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden()) {
     return;
   }
 
   ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 }
 
 }  // namespace content