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

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 53b8839462b97f2a6fd47a3cf42e0887bef3b4d8..36716ec87b033ccb7a52503e26d32438e14b1ee9 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -62,6 +62,7 @@
 #include "webkit/renderer/compositor_bindings/web_rendering_stats_impl.h"
 
 #if defined(OS_ANDROID)
+#include "base/android/sys_utils.h"
 #include "content/renderer/android/synchronous_compositor_factory.h"
 #endif
 
@@ -643,10 +644,33 @@ bool RenderWidget::ForceCompositingModeEnabled() {
 scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
+  // 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)
-   if (SynchronousCompositorFactory* factory =
-       SynchronousCompositorFactory::GetInstance()) {
-    return factory->CreateOutputSurface(routing_id());
+  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;
+  const size_t max_transfer_buffer_usage_bytes =
+      2 * kMsPerFrame * kMaxBytesUploadedPerMs;
+
+#if defined(OS_ANDROID)
+  if (SynchronousCompositorFactory* factory =
+      SynchronousCompositorFactory::GetInstance()) {
+    return factory->CreateOutputSurface(routing_id(),
+                                        max_transfer_buffer_usage_bytes);
   }
 #endif
 
@@ -670,10 +694,11 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
   attributes.stencil = false;
   if (command_line.HasSwitch(cc::switches::kForceDirectLayerDrawing))
     attributes.stencil = true;
+
   scoped_refptr<ContextProviderCommandBuffer> context_provider;
   if (!fallback) {
     context_provider = ContextProviderCommandBuffer::Create(
-        CreateGraphicsContext3D(attributes));
+        CreateGraphicsContext3D(attributes, max_transfer_buffer_usage_bytes));
   }
 
   if (!context_provider.get()) {
@@ -688,7 +713,8 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
         output_surface_id,
         NULL,
         software_device.Pass(),
-        true));
+        true,
+        max_transfer_buffer_usage_bytes));
   }
 
   if (command_line.HasSwitch(switches::kEnableDelegatedRenderer) &&
@@ -699,7 +725,8 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
             routing_id(),
             output_surface_id,
             context_provider,
-            scoped_ptr<cc::SoftwareOutputDevice>()));
+            scoped_ptr<cc::SoftwareOutputDevice>(),
+            max_transfer_buffer_usage_bytes));
   }
   if (command_line.HasSwitch(cc::switches::kCompositeToMailbox)) {
     DCHECK(is_threaded_compositing_enabled_);
@@ -708,7 +735,8 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
             routing_id(),
             output_surface_id,
             context_provider,
-            scoped_ptr<cc::SoftwareOutputDevice>()));
+            scoped_ptr<cc::SoftwareOutputDevice>(),
+            max_transfer_buffer_usage_bytes));
   }
   bool use_swap_compositor_frame_message = false;
   return scoped_ptr<cc::OutputSurface>(
@@ -717,7 +745,8 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
           output_surface_id,
           context_provider,
           scoped_ptr<cc::SoftwareOutputDevice>(),
-          use_swap_compositor_frame_message));
+          use_swap_compositor_frame_message,
+          max_transfer_buffer_usage_bytes));
 }
 
 void RenderWidget::OnViewContextSwapBuffersAborted() {
@@ -2526,7 +2555,8 @@ bool RenderWidget::HasTouchEventHandlersAt(const gfx::Point& point) const {
 
 scoped_ptr<WebGraphicsContext3DCommandBufferImpl>
 RenderWidget::CreateGraphicsContext3D(
-    const WebKit::WebGraphicsContext3D::Attributes& attributes) {
+    const WebKit::WebGraphicsContext3D::Attributes& attributes,
+    size_t max_bytes_pending_upload) {
   if (!webwidget_)
     return scoped_ptr<WebGraphicsContext3DCommandBufferImpl>();
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -2539,10 +2569,19 @@ RenderWidget::CreateGraphicsContext3D(
           RenderThreadImpl::current(),
           weak_ptr_factory_.GetWeakPtr()));
 
-  if (!context->InitializeWithDefaultBufferSizes(
+  // We keep the MappedMemoryReclaimLimit the same as the upload limit
+  // to avoid unnecessarily stalling the compositor thread.
+  const size_t kMappedMemoryReclaimLimit = max_bytes_pending_upload;
+
+  if (!context->Initialize(
           attributes,
           false /* bind generates resources */,
-          CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE))
+          CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE,
+          kDefaultCommandBufferSize,
+          kDefaultStartTransferBufferSize,
+          kDefaultMinTransferBufferSize,
+          kDefaultMaxTransferBufferSize,
+          kMappedMemoryReclaimLimit))
     return scoped_ptr<WebGraphicsContext3DCommandBufferImpl>();
   return context.Pass();
 }