Bug 1154231 - Part 2. Use LRU to manage remote layers. r=mattwoodrow

b2g/app/b2g.js

@@ -1140,3 +1140,6 @@ pref("dom.activities.developer_mode_only", "import-app");
 // mulet apparently loads firefox.js as well as b2g.js, so we have to explicitly
 // disable serviceworkers here to get them disabled in mulet.
 pref("dom.serviceWorkers.enabled", false);
+
+// Retain at most 10 processes' layers buffers
+pref("layers.compositor-lru-size", 10);

dom/ipc/TabChild.cpp

@@ -2985,17 +2985,23 @@ TabChild::NotifyPainted()
 void
 TabChild::MakeVisible()
 {
-    if (mWidget) {
-        mWidget->Show(true);
-    }
+  CompositorChild* compositor = CompositorChild::Get();
+  compositor->SendNotifyVisible(mLayersId);
+
+  if (mWidget) {
+    mWidget->Show(true);
+  }
 }
 
 void
 TabChild::MakeHidden()
 {
-    if (mWidget) {
-        mWidget->Show(false);
-    }
+  CompositorChild* compositor = CompositorChild::Get();
+  compositor->SendNotifyHidden(mLayersId);
+
+  if (mWidget) {
+    mWidget->Show(false);
+  }
 }
 
 void
@@ -3137,6 +3143,17 @@ TabChild::DidComposite(uint64_t aTransactionId)
   manager->DidComposite(aTransactionId);
 }
 
+void
+TabChild::ClearCachedResources()
+{
+  MOZ_ASSERT(mWidget);
+  MOZ_ASSERT(mWidget->GetLayerManager());
+  MOZ_ASSERT(mWidget->GetLayerManager()->GetBackendType() == LayersBackend::LAYERS_CLIENT);
+
+  ClientLayerManager *manager = static_cast<ClientLayerManager*>(mWidget->GetLayerManager());
+  manager->ClearCachedResources();
+}
+
 NS_IMETHODIMP
 TabChild::OnShowTooltip(int32_t aXCoords, int32_t aYCoords, const char16_t *aTipText)
 {

dom/ipc/TabChild.h

@@ -474,6 +474,7 @@ public:
     static TabChild* GetFrom(uint64_t aLayersId);
 
     void DidComposite(uint64_t aTransactionId);
+    void ClearCachedResources();
 
     static inline TabChild*
     GetFrom(nsIDOMWindow* aWindow)

gfx/layers/ipc/CompositorChild.cpp

@@ -372,6 +372,16 @@ CompositorChild::AddOverfillObserver(ClientLayerManager* aLayerManager)
   mOverfillObservers.AppendElement(aLayerManager);
 }
 
+bool
+CompositorChild::RecvClearCachedResources(const uint64_t& aId)
+{
+  dom::TabChild* child = dom::TabChild::GetFrom(aId);
+  if (child) {
+    child->ClearCachedResources();
+  }
+  return true;
+}
+
 void
 CompositorChild::ActorDestroy(ActorDestroyReason aWhy)
 {
@@ -549,6 +559,26 @@ CompositorChild::SendResume()
   return PCompositorChild::SendResume();
 }
 
+bool
+CompositorChild::SendNotifyHidden(const uint64_t& id)
+{
+  MOZ_ASSERT(mCanSend);
+  if (!mCanSend) {
+    return true;
+  }
+  return PCompositorChild::SendNotifyHidden(id);
+}
+
+bool
+CompositorChild::SendNotifyVisible(const uint64_t& id)
+{
+  MOZ_ASSERT(mCanSend);
+  if (!mCanSend) {
+    return true;
+  }
+  return PCompositorChild::SendNotifyVisible(id);
+}
+
 bool
 CompositorChild::SendNotifyChildCreated(const uint64_t& id)
 {

gfx/layers/ipc/CompositorChild.h

@@ -70,6 +70,9 @@ public:
 
   void AddOverfillObserver(ClientLayerManager* aLayerManager);
 
+  virtual bool
+  RecvClearCachedResources(const uint64_t& id) override;
+
   virtual bool
   RecvDidComposite(const uint64_t& aId, const uint64_t& aTransactionId) override;
 
@@ -106,6 +109,8 @@ public:
   bool SendWillStop();
   bool SendPause();
   bool SendResume();
+  bool SendNotifyHidden(const uint64_t& id);
+  bool SendNotifyVisible(const uint64_t& id);
   bool SendNotifyChildCreated(const uint64_t& id);
   bool SendAdoptChild(const uint64_t& id);
   bool SendMakeSnapshot(const SurfaceDescriptor& inSnapshot, const gfx::IntRect& dirtyRect);

gfx/layers/ipc/CompositorLRU.cpp

@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorLRU.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/unused.h"
+
+#include "CompositorParent.h"
+
+namespace mozilla {
+namespace layers {
+
+mozilla::StaticRefPtr<CompositorLRU> CompositorLRU::sSingleton;
+
+void
+CompositorLRU::Init()
+{
+  unused << GetSingleton();
+}
+
+CompositorLRU*
+CompositorLRU::GetSingleton()
+{
+  if (sSingleton) {
+    return sSingleton;
+  }
+  sSingleton = new CompositorLRU();
+  ClearOnShutdown(&sSingleton);
+
+  return sSingleton;
+}
+
+CompositorLRU::CompositorLRU()
+{
+  mLRUSize = Preferences::GetUint("layers.compositor-lru-size", uint32_t(0));
+}
+
+CompositorLRU::~CompositorLRU()
+{
+}
+
+void
+CompositorLRU::Add(PCompositorParent* aCompositor, const uint64_t& aId)
+{
+  auto index = mLRU.IndexOf(std::make_pair(aCompositor, aId));
+  if (index != nsTArray<CompositorLayerPair>::NoIndex) {
+    return;
+  }
+
+  if (mLRUSize == 0) {
+    unused << aCompositor->SendClearCachedResources(aId);
+    return;
+  }
+
+  if (mLRU.Length() == mLRUSize) {
+    CompositorLayerPair victim = mLRU.LastElement();
+    unused << victim.first->SendClearCachedResources(victim.second);
+    mLRU.RemoveElement(victim);
+  }
+  mLRU.InsertElementAt(0, std::make_pair(aCompositor, aId));
+}
+
+void
+CompositorLRU::Remove(PCompositorParent* aCompositor, const uint64_t& aId)
+{
+  if (mLRUSize == 0) {
+    return;
+  }
+
+  auto index = mLRU.IndexOf(std::make_pair(aCompositor, aId));
+
+  if (index == nsTArray<PCompositorParent*>::NoIndex) {
+    return;
+  }
+
+  mLRU.RemoveElementAt(index);
+}
+
+void
+CompositorLRU::Remove(PCompositorParent* aCompositor)
+{
+  if (mLRUSize == 0) {
+    return;
+  }
+
+  for (int32_t i = mLRU.Length() - 1; i >= 0; --i) {
+    if (mLRU[i].first == aCompositor) {
+      mLRU.RemoveElementAt(i);
+    }
+  }
+}
+
+} // namespace layers
+} // namespace mozilla

gfx/layers/ipc/CompositorLRU.h

@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_CompositorLRU_h
+#define mozilla_CompositorLRU_h
+
+#include "mozilla/StaticPtr.h"
+
+#include "nsISupportsImpl.h"
+#include "nsTArray.h"
+
+#include <utility>
+
+namespace mozilla {
+namespace layers {
+
+class PCompositorParent;
+
+class CompositorLRU final
+{
+  typedef std::pair<PCompositorParent*, uint64_t> CompositorLayerPair;
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorLRU)
+
+  static void Init();
+  static CompositorLRU* GetSingleton();
+
+  /**
+   * Adds the (PCompositorParent, LayerId) pair to the LRU pool. If
+   * the pool size grows over mLRUSize, the oldest PCompositorParent
+   * is evicted.
+   */
+  void Add(PCompositorParent* aCompositor, const uint64_t& id);
+
+  /**
+   * Remove the (PCompositorParent, LayersId) pair from the LRU pool.
+   */
+  void Remove(PCompositorParent* aCompositor, const uint64_t& id);
+
+  /**
+   * Remove all PCompositorParents from the LRU pool.
+   */
+  void Remove(PCompositorParent* aCompositor);
+
+private:
+  static StaticRefPtr<CompositorLRU> sSingleton;
+
+  CompositorLRU();
+  ~CompositorLRU();
+  uint32_t mLRUSize;
+  nsTArray<CompositorLayerPair> mLRU;
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#endif // mozilla_CompositorLRU_h

gfx/layers/ipc/CompositorParent.cpp

@@ -34,6 +34,7 @@
 #include "mozilla/layers/AsyncCompositionManager.h"
 #include "mozilla/layers/BasicCompositor.h"  // for BasicCompositor
 #include "mozilla/layers/Compositor.h"  // for Compositor
+#include "mozilla/layers/CompositorLRU.h"  // for CompositorLRU
 #include "mozilla/layers/CompositorOGL.h"  // for CompositorOGL
 #include "mozilla/layers/CompositorTypes.h"
 #include "mozilla/layers/LayerManagerComposite.h"
@@ -1686,6 +1687,8 @@ public:
   virtual bool RecvStop() override { return true; }
   virtual bool RecvPause() override { return true; }
   virtual bool RecvResume() override { return true; }
+  virtual bool RecvNotifyHidden(const uint64_t& id) override;
+  virtual bool RecvNotifyVisible(const uint64_t& id) override;
   virtual bool RecvNotifyChildCreated(const uint64_t& child) override;
   virtual bool RecvAdoptChild(const uint64_t& child) override { return false; }
   virtual bool RecvMakeSnapshot(const SurfaceDescriptor& aInSnapshot,
@@ -1841,6 +1844,22 @@ CompositorParent::GetIndirectShadowTree(uint64_t aId)
   return &cit->second;
 }
 
+bool
+CrossProcessCompositorParent::RecvNotifyHidden(const uint64_t& id)
+{
+  nsRefPtr<CompositorLRU> lru = CompositorLRU::GetSingleton();
+  lru->Add(this, id);
+  return true;
+}
+
+bool
+CrossProcessCompositorParent::RecvNotifyVisible(const uint64_t& id)
+{
+  nsRefPtr<CompositorLRU> lru = CompositorLRU::GetSingleton();
+  lru->Remove(this, id);
+  return true;
+}
+
 bool
 CrossProcessCompositorParent::RecvRequestNotifyAfterRemotePaint()
 {
@@ -1851,6 +1870,9 @@ CrossProcessCompositorParent::RecvRequestNotifyAfterRemotePaint()
 void
 CrossProcessCompositorParent::ActorDestroy(ActorDestroyReason aWhy)
 {
+  nsRefPtr<CompositorLRU> lru = CompositorLRU::GetSingleton();
+  lru->Remove(this);
+
   MessageLoop::current()->PostTask(
     FROM_HERE,
     NewRunnableMethod(this, &CrossProcessCompositorParent::DeferredDestroy));

gfx/layers/ipc/CompositorParent.h

@@ -234,6 +234,8 @@ public:
   virtual bool RecvStop() override;
   virtual bool RecvPause() override;
   virtual bool RecvResume() override;
+  virtual bool RecvNotifyHidden(const uint64_t& id) override { return true; }
+  virtual bool RecvNotifyVisible(const uint64_t& id) override { return true; }
   virtual bool RecvNotifyChildCreated(const uint64_t& child) override;
   virtual bool RecvAdoptChild(const uint64_t& child) override;
   virtual bool RecvMakeSnapshot(const SurfaceDescriptor& aInSnapshot,

gfx/layers/ipc/PCompositor.ipdl

@@ -70,6 +70,12 @@ child:
    */
   async UpdatePluginVisibility(uintptr_t[] aVisibleIdList);
 
+  /**
+   * Drop any buffers that might be retained on the child compositor
+   * side.
+   */
+  async ClearCachedResources(uint64_t id);
+
 parent:
   // Child sends the parent a request for fill ratio numbers.
   async RequestOverfill();
@@ -85,6 +91,14 @@ parent:
   sync Pause();
   sync Resume();
 
+  // The child layer tree is hidden. id is the layers id of the child
+  // layer tree.
+  async NotifyHidden(uint64_t id);
+
+  // The child layer tree is visible. id is the layers id of the child
+  // layer tree.
+  async NotifyVisible(uint64_t id);
+
   async NotifyChildCreated(uint64_t id);
   async AdoptChild(uint64_t id);
 

gfx/layers/moz.build

@@ -139,6 +139,7 @@ EXPORTS.mozilla.layers += [
     'ipc/CompositableForwarder.h',
     'ipc/CompositableTransactionParent.h',
     'ipc/CompositorChild.h',
+    'ipc/CompositorLRU.h',
     'ipc/CompositorParent.h',
     'ipc/FenceUtils.h',
     'ipc/ImageBridgeChild.h',
@@ -294,6 +295,7 @@ UNIFIED_SOURCES += [
     'ipc/CompositableTransactionParent.cpp',
     'ipc/CompositorBench.cpp',
     'ipc/CompositorChild.cpp',
+    'ipc/CompositorLRU.cpp',
     'ipc/CompositorParent.cpp',
     'ipc/ImageBridgeChild.cpp',
     'ipc/ImageBridgeParent.cpp',

layout/build/nsLayoutStatics.cpp

@@ -139,6 +139,7 @@ using namespace mozilla::system;
 #include "CameraPreferences.h"
 #include "TouchManager.h"
 #include "MediaDecoder.h"
+#include "mozilla/layers/CompositorLRU.h"
 
 using namespace mozilla;
 using namespace mozilla::net;
@@ -320,6 +321,8 @@ nsLayoutStatics::Initialize()
 
   PromiseDebugging::Init();
 
+  layers::CompositorLRU::Init();
+
   return NS_OK;
 }
 

modules/libpref/init/all.js

@@ -4148,6 +4148,9 @@ pref("layers.force-active", false);
 // platform and are the optimal surface type.
 pref("layers.gralloc.disable", false);
 
+// Don't use compositor-lru on this platform
+pref("layers.compositor-lru-size", 0);
+
 // Enable/Disable the geolocation API for content
 pref("geo.enabled", true);