Bug 1482109 - Hook the memory pressure observer up with WebRender. r=sotaro

--HG--
extra : rebase_source : e23d9db4ffff5d1994f476e660f7f6cbe52e6ad6

gfx/layers/ipc/CompositorBridgeParent.cpp

@@ -1912,6 +1912,17 @@ CompositorBridgeParent::DeallocPWebRenderBridgeParent(PWebRenderBridgeParent* aA
   return true;
 }
 
+void
+CompositorBridgeParent::NotifyMemoryPressure()
+{
+  if (mWrBridge) {
+    RefPtr<wr::WebRenderAPI> api = mWrBridge->GetWebRenderAPI();
+    if (api) {
+      api->NotifyMemoryPressure();
+    }
+  }
+}
+
 RefPtr<WebRenderBridgeParent>
 CompositorBridgeParent::GetWebRenderBridgeParent() const
 {

gfx/layers/ipc/CompositorBridgeParent.h

@@ -175,6 +175,8 @@ public:
     MOZ_CRASH();
   }
 
+  virtual void NotifyMemoryPressure() {}
+
 protected:
   ~CompositorBridgeParentBase() override;
 
@@ -236,6 +238,8 @@ public:
 
   mozilla::ipc::IPCResult RecvAllPluginsCaptured() override;
 
+  virtual void NotifyMemoryPressure() override;
+
   void ActorDestroy(ActorDestroyReason why) override;
 
   void ShadowLayersUpdated(LayerTransactionParent* aLayerTree,

gfx/layers/ipc/CompositorManagerParent.cpp

@@ -288,5 +288,16 @@ CompositorManagerParent::RecvRemoveSharedSurface(const wr::ExternalImageId& aId)
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult
+CompositorManagerParent::RecvNotifyMemoryPressure()
+{
+  nsTArray<PCompositorBridgeParent*> compositorBridges;
+  ManagedPCompositorBridgeParent(compositorBridges);
+  for (auto bridge : compositorBridges) {
+    static_cast<CompositorBridgeParentBase*>(bridge)->NotifyMemoryPressure();
+  }
+  return IPC_OK();
+}
+
 } // namespace layers
 } // namespace mozilla

gfx/layers/ipc/CompositorManagerParent.h

@@ -44,6 +44,8 @@ public:
                                                const SurfaceDescriptorShared& aDesc) override;
   mozilla::ipc::IPCResult RecvRemoveSharedSurface(const wr::ExternalImageId& aId) override;
 
+  virtual mozilla::ipc::IPCResult RecvNotifyMemoryPressure() override;
+
   void BindComplete();
   void ActorDestroy(ActorDestroyReason aReason) override;
 

gfx/layers/ipc/PCompositorManager.ipdl

@@ -75,6 +75,8 @@ parent:
 
   async AddSharedSurface(ExternalImageId aId, SurfaceDescriptorShared aDesc);
   async RemoveSharedSurface(ExternalImageId aId);
+
+  async NotifyMemoryPressure();
 };
 
 } // layers

gfx/thebes/gfxPlatform.cpp

@@ -471,6 +471,12 @@ gfxPlatform::OnMemoryPressure(layers::MemoryPressureReason aWhy)
     gfxGradientCache::PurgeAllCaches();
     PurgeSkiaFontCache();
     PurgeSkiaGPUCache();
+    if (XRE_IsParentProcess()) {
+      layers::CompositorManagerChild* manager = CompositorManagerChild::GetInstance();
+      if (manager) {
+        manager->SendNotifyMemoryPressure();
+      }
+    }
 }
 
 gfxPlatform::gfxPlatform()

gfx/webrender_bindings/WebRenderAPI.cpp

@@ -502,6 +502,12 @@ WebRenderAPI::Resume()
     return result;
 }
 
+void
+WebRenderAPI::NotifyMemoryPressure()
+{
+  wr_api_notify_memory_pressure(mDocHandle);
+}
+
 void
 WebRenderAPI::WakeSceneBuilder()
 {

gfx/webrender_bindings/WebRenderAPI.h

@@ -206,6 +206,8 @@ public:
   void WakeSceneBuilder();
   void FlushSceneBuilder();
 
+  void NotifyMemoryPressure();
+
   wr::WrIdNamespace GetNamespace();
   uint32_t GetMaxTextureSize() const { return mMaxTextureSize; }
   bool GetUseANGLE() const { return mUseANGLE; }

gfx/webrender_bindings/src/bindings.rs

@@ -1029,6 +1029,11 @@ pub unsafe extern "C" fn wr_api_shut_down(dh: &mut DocumentHandle) {
     dh.api.shut_down();
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn wr_api_notify_memory_pressure(dh: &mut DocumentHandle) {
+    dh.api.notify_memory_pressure();
+}
+
 /// cbindgen:postfix=WR_DESTRUCTOR_SAFE_FUNC
 #[no_mangle]
 pub unsafe extern "C" fn wr_api_clear_all_caches(dh: &mut DocumentHandle) {

gfx/webrender_bindings/webrender_ffi_generated.h

@@ -1097,6 +1097,10 @@ bool wr_api_hit_test(DocumentHandle *aDh,
                      uint16_t *aOutHitInfo)
 WR_FUNC;
 
+WR_INLINE
+void wr_api_notify_memory_pressure(DocumentHandle *aDh)
+WR_FUNC;
+
 WR_INLINE
 void wr_api_send_external_event(DocumentHandle *aDh,
                                 uintptr_t aEvt)