Chromecast: forcibly trigger GC in low-memory situations.

chromecast/renderer/cast_content_renderer_client.cc

 // Copyright 2014 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 "chromecast/renderer/cast_content_renderer_client.h"
 
 #include <sys/sysinfo.h>
 
 #include "base/command_line.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "chromecast/common/chromecast_switches.h"
 #include "chromecast/renderer/cast_media_load_deferrer.h"
 #include "chromecast/renderer/cast_render_process_observer.h"
 #include "chromecast/renderer/key_systems_cast.h"
 #include "chromecast/renderer/media/cma_media_renderer_factory.h"
 #include "components/dns_prefetch/renderer/prescient_networking_dispatcher.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
 #include "crypto/nss_util.h"
 #include "third_party/WebKit/public/platform/WebColor.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
 #include "third_party/WebKit/public/web/WebView.h"
 
 namespace chromecast {
 namespace shell {
 
 namespace {
 
+#if defined(ARCH_CPU_ARM_FAMILY) && !defined(OS_ANDROID)
+// These memory thresholds are set for Chromecast. See the UMA histogram
+// Platform.MeminfoMemFree when tuning.
+const int kCriticalMinFreeMemMB = 24;
+const int kModerateMinFreeMemMB = 48;
+const int kPollingIntervalMS = 5000;

[lcwu1, 2015/01/08 18:52:12]

These numbers should be platform/product dependent and shouldn't be applied
across all the ARM family. I am fine with this CL landed first. But let's leave
a TODO to re-structure the code and move them (and probably the function below)
to the internal platform/vendor specific location.

[gunsch, 2015/01/08 19:02:08]

Done.

+
+void PlatformPollFreemem(void) {
+  struct sysinfo sys;
+
+  if (sysinfo(&sys) == -1) {
+    LOG(ERROR) << "platform_poll_freemem(): sysinfo failed";
+  } else {
+    int free_mem_mb = static_cast<int64_t>(sys.freeram) *
+        sys.mem_unit / (1024 * 1024);
+
+    if (free_mem_mb <= kModerateMinFreeMemMB) {
+      if (free_mem_mb <= kCriticalMinFreeMemMB) {
+        // Memory is getting really low, we need to do whatever we can to
+        // prevent deadlocks and interfering with other processes.
+        base::MemoryPressureListener::NotifyMemoryPressure(
+            base::MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+      } else {
+        // There is enough memory, but it is starting to get low.
+        base::MemoryPressureListener::NotifyMemoryPressure(
+            base::MemoryPressureListener::MEMORY_PRESSURE_MODERATE);
+      }
+    }
+  }
+
+  // Setup next poll.
+  base::MessageLoopProxy::current()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&PlatformPollFreemem),
+      base::TimeDelta::FromMilliseconds(kPollingIntervalMS));
+}
+#endif
+
 // Default background color to set for WebViews. WebColor is in ARGB format
 // though the comment of WebColor says it is in RGBA.
 const blink::WebColor kColorBlack = 0xFF000000;
 
 }  // namespace
 
 CastContentRendererClient::CastContentRendererClient() {
 }
 
 CastContentRendererClient::~CastContentRendererClient() {
 }
 
 void CastContentRendererClient::RenderThreadStarted() {
 #if defined(USE_NSS)
   // Note: Copied from chrome_render_process_observer.cc to fix b/8676652.
   //
   // On platforms where the system NSS shared libraries are used,
   // initialize NSS now because it won't be able to load the .so's
   // after entering the sandbox.
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (!command_line->HasSwitch(switches::kSingleProcess))
     crypto::InitNSSSafely();
 #endif
 
+#if defined(ARCH_CPU_ARM_FAMILY) && !defined(OS_ANDROID)
+  PlatformPollFreemem();
+#endif
+
   cast_observer_.reset(new CastRenderProcessObserver());
 
   prescient_networking_dispatcher_.reset(
       new dns_prefetch::PrescientNetworkingDispatcher());
 }
 
 void CastContentRendererClient::RenderViewCreated(
     content::RenderView* render_view) {
   blink::WebView* webview = render_view->GetWebView();
   if (webview) {
@@ skipping 38 matching lines @@
     closure.Run();
     return;
   }
 
   // Lifetime is tied to |render_frame| via content::RenderFrameObserver.
   new CastMediaLoadDeferrer(render_frame, closure);
 }
 
 }  // namespace shell
 }  // namespace chromecast