Invoke OnTrimMemoryImmediately when memory state is SUSPENDED

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 <utility>
@@ skipping 1751 matching lines @@
   ChildThreadImpl::OnProcessPurgeAndSuspend();
   DCHECK(!is_renderer_suspended_);
   if (!RendererIsHidden())
     return;
   is_renderer_suspended_ = true;
   if (base::FeatureList::IsEnabled(features::kPurgeAndSuspend)) {
     // TODO(tasak): After enabling MemoryCoordinator, remove this Notify
     // and follow MemoryCoordinator's request.
     base::MemoryCoordinatorClientRegistry::GetInstance()->Notify(
         base::MemoryState::SUSPENDED);
+    RenderThreadImpl::OnSyncMemoryPressure(

[bashi, 2016/11/11 07:45:23]

nit: Could you add a comment why we call this and future plan (integrate this
notification with memory coordinator) ?

[tasak, 2016/11/14 06:07:58]

Done.

+        base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL);

[haraken, 2016/11/11 08:58:40]

Just to confirm: This triggers Oilpan's GC too, right?

Also, we might want to call Partitions::decommitFreeableMemory() and some
clean-up method of tcmalloc (if any) after forcing the GCs.

[tasak, 2016/11/14 06:07:58]

Yes.
Manually tested purge+suspend without action_runner.ForceGarbageCollection().
I compared purge+suspend with just backgrounded (no purge and no suspend). v8
and blink_gc memory usages were reduced.
I think, currently we cannot control the order of "purge". Those methods are
invoked, but it is not possible to say the methods are invoked at last.

     renderer_scheduler_->SuspendRenderer();
   }
 
   // Since purging is not a synchronous task (e.g. v8 GC, oilpan GC, ...),
   // we need to wait until the task is finished. So wait 15 seconds and
   // update purge+suspend UMA histogram.
   // TODO(tasak): use MemoryCoordinator's callback to report purge+suspend
   // UMA when MemoryCoordinator is available.
   GetRendererScheduler()->DefaultTaskRunner()->PostDelayedTask(
       FROM_HERE, record_purge_suspend_metric_closure_.callback(),
@@ skipping 695 matching lines @@
   }
 }
 
 void RenderThreadImpl::OnRendererInterfaceRequest(
     mojom::RendererAssociatedRequest request) {
   DCHECK(!renderer_binding_.is_bound());
   renderer_binding_.Bind(std::move(request));
 }
 
 }  // namespace content