Bug 1469496 - Handle video memory purge with WebRender. r=sotaro

gfx/layers/ipc/CompositorBridgeParent.cpp

@@ -2354,6 +2354,14 @@ CompositorBridgeParent::NotifyWebRenderError(wr::WebRenderError aError)
   Unused << SendNotifyWebRenderError(aError);
 }
 
+void
+CompositorBridgeParent::NotifyWebRenderContextPurge()
+{
+  MOZ_ASSERT(CompositorLoop() == MessageLoop::current());
+  RefPtr<wr::WebRenderAPI> api = mWrBridge->GetWebRenderAPI();
+  api->ClearAllCaches();
+}
+
 #if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
 //#define PLUGINS_LOG(...) printf_stderr("CP [%s]: ", __FUNCTION__);
 //                         printf_stderr(__VA_ARGS__);

gfx/layers/ipc/CompositorBridgeParent.h

@@ -274,6 +274,7 @@ public:
   bool IsSameProcess() const override;
 
   void NotifyWebRenderError(wr::WebRenderError aError);
+  void NotifyWebRenderContextPurge();
   void NotifyPipelineRendered(const wr::PipelineId& aPipelineId,
                               const wr::Epoch& aEpoch,
                               TimeStamp& aCompositeStart,

gfx/webrender_bindings/RendererOGL.cpp

@@ -95,6 +95,12 @@ RendererOGL::Update()
   }
 }
 
+static void
+DoNotifyWebRenderContextPurge(layers::CompositorBridgeParent* aBridge)
+{
+  aBridge->NotifyWebRenderContextPurge();
+}
+
 bool
 RendererOGL::UpdateAndRender(bool aReadback)
 {
@@ -150,6 +156,18 @@ RendererOGL::UpdateAndRender(bool aReadback)
   mFrameStartTime = TimeStamp();
 #endif
 
+  gl::GLContext* gl = mCompositor->gl();
+  if (gl->IsSupported(gl::GLFeature::robustness)) {
+    GLenum resetStatus = gl->fGetGraphicsResetStatus();
+    if (resetStatus == LOCAL_GL_PURGED_CONTEXT_RESET_NV) {
+      layers::CompositorThreadHolder::Loop()->PostTask(NewRunnableFunction(
+        "DoNotifyWebRenderContextPurgeRunnable",
+        &DoNotifyWebRenderContextPurge,
+        mBridge
+      ));
+    }
+  }
+
   // TODO: Flush pending actions such as texture deletions/unlocks and
   //       textureHosts recycling.
 

gfx/webrender_bindings/WebRenderAPI.cpp

@@ -422,6 +422,12 @@ WebRenderAPI::Readback(const TimeStamp& aStartTime,
     task.Wait();
 }
 
+void
+WebRenderAPI::ClearAllCaches()
+{
+  wr_api_clear_all_caches(mDocHandle);
+}
+
 void
 WebRenderAPI::Pause()
 {

gfx/webrender_bindings/WebRenderAPI.h

@@ -198,6 +198,8 @@ public:
 
   void Readback(const TimeStamp& aStartTime, gfx::IntSize aSize, uint8_t *aBuffer, uint32_t aBufferSize);
 
+  void ClearAllCaches();
+
   void Pause();
   bool Resume();
 

gfx/webrender_bindings/src/bindings.rs

@@ -1029,6 +1029,12 @@ pub unsafe extern "C" fn wr_api_shut_down(dh: &mut DocumentHandle) {
     dh.api.shut_down();
 }
 
+/// cbindgen:postfix=WR_DESTRUCTOR_SAFE_FUNC
+#[no_mangle]
+pub unsafe extern "C" fn wr_api_clear_all_caches(dh: &mut DocumentHandle) {
+    dh.api.send_debug_cmd(DebugCommand::ClearCaches(ClearCache::all()));
+}
+
 fn make_transaction(do_async: bool) -> Transaction {
     let mut transaction = Transaction::new();
     // Ensure that we either use async scene building or not based on the

gfx/webrender_bindings/webrender_ffi_generated.h

@@ -1050,6 +1050,10 @@ void wr_api_capture(DocumentHandle *aDh,
                     uint32_t aBitsRaw)
 WR_FUNC;
 
+WR_INLINE
+void wr_api_clear_all_caches(DocumentHandle *aDh)
+WR_DESTRUCTOR_SAFE_FUNC;
+
 WR_INLINE
 void wr_api_clone(DocumentHandle *aDh,
                   DocumentHandle **aOutHandle)