Changeset 80307 in webkit

Timestamp:

Mar 3, 2011 5:37:11 PM (13 years ago)

Author:

Adam Roben

Message:

Throw away DrawingAreaProxyImpl's backing store after not painting for 5 seconds

The intent is to save memory for views that aren't painting.

Fixes <​http://webkit.org/b/51262> <rdar://problem/8782537> WebPageProxy should delete its
backing store after not painting for a while

Reviewed by Anders Carlsson.

• UIProcess/DrawingAreaProxyImpl.cpp:

(WebKit::DrawingAreaProxyImpl::DrawingAreaProxyImpl): Initialize our timer.
(WebKit::DrawingAreaProxyImpl::paint): Don't bail if we don't have a backing store (but do
bail if we're in accelerated compositing mode); we might have thrown it away to save memory
but now are being asked to paint by the view. The existing code in this function will handle
getting a new backing store if possible by blocking for a little while to try to receive a
DidUpdateBackingStoreState message. Added an assertion that we do have a backing store if we
don't have any outstanding UpdateBackingStoreState requests. After painting, call
discardBackingStoreSoon to update our timer.
(WebKit::DrawingAreaProxyImpl::discardBackingStoreSoon): Set the timer for 5 seconds in the
future.
(WebKit::DrawingAreaProxyImpl::discardBackingStore): Throw away the backing store, and tell
the web process we'll need a full backing store update on the next paint.

• UIProcess/DrawingAreaProxyImpl.h: Added m_discardBackingStoreTimer.

Location:

trunk/Source/WebKit2

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/DrawingAreaProxyImpl.cpp (modified) (4 diffs)
• UIProcess/DrawingAreaProxyImpl.h (modified) (3 diffs)

trunk/Source/WebKit2/ChangeLog

@@ +1 @@
+2011-03-03  Adam Roben  <aroben@apple.com>
+
+        Throw away DrawingAreaProxyImpl's backing store after not painting for 5 seconds
+
+        The intent is to save memory for views that aren't painting.
+
+        Fixes <http://webkit.org/b/51262> <rdar://problem/8782537> WebPageProxy should delete its
+        backing store after not painting for a while
+
+        Reviewed by Anders Carlsson.
+
+        * UIProcess/DrawingAreaProxyImpl.cpp:
+        (WebKit::DrawingAreaProxyImpl::DrawingAreaProxyImpl): Initialize our timer.
+        (WebKit::DrawingAreaProxyImpl::paint): Don't bail if we don't have a backing store (but do
+        bail if we're in accelerated compositing mode); we might have thrown it away to save memory
+        but now are being asked to paint by the view. The existing code in this function will handle
+        getting a new backing store if possible by blocking for a little while to try to receive a
+        DidUpdateBackingStoreState message. Added an assertion that we do have a backing store if we
+        don't have any outstanding UpdateBackingStoreState requests. After painting, call
+        discardBackingStoreSoon to update our timer.
+        (WebKit::DrawingAreaProxyImpl::discardBackingStoreSoon): Set the timer for 5 seconds in the
+        future.
+        (WebKit::DrawingAreaProxyImpl::discardBackingStore): Throw away the backing store, and tell
+        the web process we'll need a full backing store update on the next paint.
+
+        * UIProcess/DrawingAreaProxyImpl.h: Added m_discardBackingStoreTimer.
+
 2011-03-03  Adam Roben  <aroben@apple.com>
 

trunk/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp

@@ -53 +53 @@
     , m_nextBackingStoreStateID(0)
     , m_isWaitingForDidUpdateBackingStoreState(false)
+    , m_discardBackingStoreTimer(RunLoop::current(), this, &DrawingAreaProxyImpl::discardBackingStore)
 {
 }
@@ -67 +68 @@
     unpaintedRegion = rect;
 
-    if (!m_backingStore)
-        return;
-
-    ASSERT(!isInAcceleratedCompositingMode());
+    if (isInAcceleratedCompositingMode())
+        return;
 
     ASSERT(m_currentBackingStoreStateID <= m_nextBackingStoreStateID);
@@ -89 +88 @@
         if (!m_backingStore || isInAcceleratedCompositingMode())
             return;
-    } else
+    } else {
         ASSERT(!m_isWaitingForDidUpdateBackingStoreState);
+        ASSERT(m_backingStore);
+    }
 
     m_backingStore->paint(context, rect);
     unpaintedRegion.subtract(IntRect(IntPoint(), m_backingStore->size()));
+
+    discardBackingStoreSoon();
 }
 
@@ -289 +292 @@
 }
 
+void DrawingAreaProxyImpl::discardBackingStoreSoon()
+{
+    // We'll wait this many seconds after the last paint before throwing away our backing store to save memory.
+    // FIXME: It would be smarter to make this delay based on how expensive painting is. See <http://webkit.org/b/55733>.
+    static const double discardBackingStoreDelay = 5;
+
+    m_discardBackingStoreTimer.startOneShot(discardBackingStoreDelay);
+}
+
+void DrawingAreaProxyImpl::discardBackingStore()
+{
+    m_backingStore = nullptr;
+    backingStoreStateDidChange(DoNotRespondImmediately);
+}
+
 } // namespace WebKit

trunk/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.h

@@ -30 +30 @@
 #include "DrawingAreaProxy.h"
 #include "LayerTreeContext.h"
+#include "RunLoop.h"
 #include <wtf/OwnPtr.h>
 #include <wtf/PassOwnPtr.h>
@@ -73 +74 @@
     bool isInAcceleratedCompositingMode() const { return !m_layerTreeContext.isEmpty(); }
 
+    void discardBackingStoreSoon();
+    void discardBackingStore();
+
     // The state ID corresponding to our current backing store. Updated whenever we allocate
     // a new backing store. Any messages received that correspond to an earlier state are ignored,
@@ -90 +94 @@
 
     OwnPtr<BackingStore> m_backingStore;
+
+    RunLoop::Timer<DrawingAreaProxyImpl> m_discardBackingStoreTimer;
 };