Changeset 210224 in webkit

Timestamp:

Jan 2, 2017 7:36:41 AM (7 years ago)

Author:

akling@apple.com

Message:

Discard media controls JS/CSS caches under memory pressure.
<​https://webkit.org/b/166639>

Reviewed by Antti Koivisto.

Source/WebCore:

Add a RenderTheme::purgeCaches() virtual and teach the iOS and macOS implementations
to drop their cached media controls JS/CSS strings there. The strings are only cleared
if nothing else is referencing them, which gives us a decent "weak cache" behavior.

This sheds ~300kB memory on iOS with the current media controls.

• page/MemoryRelease.cpp:

(WebCore::releaseNoncriticalMemory):

• rendering/RenderTheme.h:

(WebCore::RenderTheme::purgeCaches):

• rendering/RenderThemeIOS.h:
• rendering/RenderThemeIOS.mm:

(WebCore::RenderThemeIOS::purgeCaches):

• rendering/RenderThemeMac.h:
• rendering/RenderThemeMac.mm:

(WebCore::RenderThemeMac::purgeCaches):

Source/WTF:

• wtf/text/WTFString.h:

(WTF::String::clearImplIfNotShared): Add a helper for clearing a String if the underlying
StringImpl is not referenced by anyone else.

Location:

trunk/Source

Files:

• WTF/ChangeLog (modified) (1 diff)
• WTF/wtf/text/WTFString.h (modified) (1 diff)
• WebCore/ChangeLog (modified) (1 diff)
• WebCore/page/MemoryRelease.cpp (modified) (2 diffs)
• WebCore/rendering/RenderTheme.h (modified) (1 diff)
• WebCore/rendering/RenderThemeIOS.h (modified) (1 diff)
• WebCore/rendering/RenderThemeIOS.mm (modified) (1 diff)
• WebCore/rendering/RenderThemeMac.h (modified) (1 diff)
• WebCore/rendering/RenderThemeMac.mm (modified) (1 diff)

trunk/Source/WTF/ChangeLog

@@ +1 @@
+2017-01-02  Andreas Kling  <akling@apple.com>
+
+        Discard media controls JS/CSS caches under memory pressure.
+        <https://webkit.org/b/166639>
+
+        Reviewed by Antti Koivisto.
+
+        * wtf/text/WTFString.h:
+        (WTF::String::clearImplIfNotShared): Add a helper for clearing a String if the underlying
+        StringImpl is not referenced by anyone else.
+
 2016-12-22  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/WTF/wtf/text/WTFString.h

@@ -468 +468 @@
             return 0;
         return (*m_impl)[index];
+    }
+
+    // Turns this String empty if the StringImpl is not referenced by anyone else.
+    // This is useful for clearing String-based caches.
+    void clearImplIfNotShared()
+    {
+        if (m_impl && m_impl->hasOneRef())
+            m_impl = nullptr;
     }
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2017-01-02  Andreas Kling  <akling@apple.com>
+
+        Discard media controls JS/CSS caches under memory pressure.
+        <https://webkit.org/b/166639>
+
+        Reviewed by Antti Koivisto.
+
+        Add a RenderTheme::purgeCaches() virtual and teach the iOS and macOS implementations
+        to drop their cached media controls JS/CSS strings there. The strings are only cleared
+        if nothing else is referencing them, which gives us a decent "weak cache" behavior.
+
+        This sheds ~300kB memory on iOS with the current media controls.
+
+        * page/MemoryRelease.cpp:
+        (WebCore::releaseNoncriticalMemory):
+        * rendering/RenderTheme.h:
+        (WebCore::RenderTheme::purgeCaches):
+        * rendering/RenderThemeIOS.h:
+        * rendering/RenderThemeIOS.mm:
+        (WebCore::RenderThemeIOS::purgeCaches):
+        * rendering/RenderThemeMac.h:
+        * rendering/RenderThemeMac.mm:
+        (WebCore::RenderThemeMac::purgeCaches):
+
 2017-01-02  Carlos Garcia Campos  <cgarcia@igalia.com>
 

trunk/Source/WebCore/page/MemoryRelease.cpp

@@ -39 +39 @@
 #include "Page.h"
 #include "PageCache.h"
+#include "RenderTheme.h"
 #include "ScrollingThread.h"
 #include "StyleScope.h"
@@ -49 +50 @@
 static void releaseNoncriticalMemory()
 {
+    RenderTheme::defaultTheme()->purgeCaches();
+
     FontCache::singleton().purgeInactiveFontData();
 

trunk/Source/WebCore/rendering/RenderTheme.h

@@ -73 +73 @@
     };
 
+    virtual void purgeCaches() { }
+
     // This method is called whenever style has been computed for an element and the appearance
     // property has been set to a value other than "none".  The theme should map in all of the appropriate

trunk/Source/WebCore/rendering/RenderThemeIOS.h

@@ -122 +122 @@
     virtual ~RenderThemeIOS() { }
 
+    void purgeCaches() override;
+
     const Color& shadowColor() const;
     FloatRect addRoundedBorderClip(const RenderObject& box, GraphicsContext&, const IntRect&);

trunk/Source/WebCore/rendering/RenderThemeIOS.mm

@@ -1306 +1306 @@
 }
 
+void RenderThemeIOS::purgeCaches()
+{
+    m_legacyMediaControlsScript.clearImplIfNotShared();
+    m_mediaControlsScript.clearImplIfNotShared();
+    m_legacyMediaControlsStyleSheet.clearImplIfNotShared();
+    m_mediaControlsStyleSheet.clearImplIfNotShared();
+}
+
 String RenderThemeIOS::mediaControlsScript()
 {

trunk/Source/WebCore/rendering/RenderThemeMac.h

@@ -172 +172 @@
 
     Color systemColor(CSSValueID) const override;
+
+    void purgeCaches() override;
 
     // Get the control size based off the font. Used by some of the controls (like buttons).

trunk/Source/WebCore/rendering/RenderThemeMac.mm

@@ -247 +247 @@
 }
 
+void RenderThemeMac::purgeCaches()
+{
+    m_legacyMediaControlsScript.clearImplIfNotShared();
+    m_mediaControlsScript.clearImplIfNotShared();
+    m_legacyMediaControlsStyleSheet.clearImplIfNotShared();
+    m_mediaControlsStyleSheet.clearImplIfNotShared();
+}
+
 String RenderThemeMac::mediaControlsScript()
 {