cc: Set the mapped memory reclaim limit for the renderer compositor on Android

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index e7a7e3e0f5957e9b99ffc5f6c7c6e9b9e2f1b987..7878af85c19a575556679d095ed418b851b8862c 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -7,6 +7,10 @@
 #include <limits>
 #include <string>
 
+#if defined(OS_ANDROID)
+#include "base/android/sys_utils.h"
+#endif
+
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ -286,6 +290,30 @@ scoped_ptr<RenderWidgetCompositor> RenderWidgetCompositor::Create(
   }
 #endif
 
+// If we raster too fast we become upload bound, and pending
+// uploads consume memory. For maximum upload throughput, we would
+// want to allow for upload_throughput * pipeline_time of pending
+// uploads, after which we are just wasting memory. Since we don't
+// know our upload throughput yet, this just caps our memory usage.
+#if defined(OS_ANDROID)
+  size_t divider = 1;
+  if (base::android::SysUtils::IsLowEndDevice())
+    divider = 3;
+
+  // For reference Nexus10 can upload 1MB in about 2.5ms.
+  const size_t kMaxBytesUploadedPerMs = (2 * 1024 * 1024) / (5 * divider);
+#else
+  // For reference Chromebook Pixel can upload 1MB in about 0.5ms.
+  const size_t kMaxBytesUploadedPerMs = 1024 * 1024 * 2;
+#endif
+
+  // Assuming a two frame deep pipeline.
+  const size_t kMsPerFrame = 16;
+  settings.max_transfer_buffer_usage_bytes
+      = 2 * kMsPerFrame * kMaxBytesUploadedPerMs;
+  compositor->SetMaxTransferBufferUsageBytes(
+      settings.max_transfer_buffer_usage_bytes);
+
   if (!compositor->initialize(settings))
     return scoped_ptr<RenderWidgetCompositor>();
 
@@ -296,7 +324,8 @@ RenderWidgetCompositor::RenderWidgetCompositor(RenderWidget* widget,
                                                bool threaded)
     : threaded_(threaded),
       suppress_schedule_composite_(false),
-      widget_(widget) {
+      widget_(widget),
+      max_transfer_buffer_usage_bytes_(0) {
 }
 
 RenderWidgetCompositor::~RenderWidgetCompositor() {}
@@ -552,7 +581,8 @@ void RenderWidgetCompositor::ApplyScrollAndScale(gfx::Vector2d scroll_delta,
 
 scoped_ptr<cc::OutputSurface> RenderWidgetCompositor::CreateOutputSurface(
     bool fallback) {
-  return widget_->CreateOutputSurface(fallback);
+  return widget_->CreateOutputSurface(fallback,
+                                      max_transfer_buffer_usage_bytes_);
 }
 
 void RenderWidgetCompositor::DidInitializeOutputSurface(bool success) {
@@ -593,4 +623,9 @@ RenderWidgetCompositor::OffscreenContextProviderForCompositorThread() {
       OffscreenContextProviderForCompositorThread();
 }
 
+void RenderWidgetCompositor::SetMaxTransferBufferUsageBytes(
+    size_t max_transfer_buffer_usage_bytes) {
+  max_transfer_buffer_usage_bytes_ = max_transfer_buffer_usage_bytes;
+}
+
 }  // namespace content