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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/170973">170973</a></dd>
<dt>Author</dt> <dd>akling@apple.com</dd>
<dt>Date</dt> <dd>2014-07-10 13:24:12 -0700 (Thu, 10 Jul 2014)</dd>
</dl>
<h3>Log Message</h3>
<pre>[iOS WebKit2] Some memory pressure relief tweaks.
<https://webkit.org/b/134811>
Split memory pressure relief into critical and non-critical sections.
Non-critical relief is for clearing out things that are really not
essential, e.g unused font data, text measurement caches, etc.
On iOS, only flip the "WebKit is under memory pressure" flag when we
are under *critical* memroy pressure, rather than doing it early on
and gimping ourselves because other processes are too big.
Also added logging for when we transition in/out of system pressure.
Reviewed by Geoffrey Garen.
* platform/MemoryPressureHandler.cpp:
(WebCore::MemoryPressureHandler::releaseNoncriticalMemory):
(WebCore::MemoryPressureHandler::releaseCriticalMemory):
(WebCore::MemoryPressureHandler::releaseMemory):
* platform/MemoryPressureHandler.h:
(WebCore::MemoryPressureHandler::ReliefLogger::loggingEnabled):
* platform/cocoa/MemoryPressureHandlerCocoa.mm:
(WebCore::MemoryPressureHandler::install):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebCoreChangeLog">trunk/Source/WebCore/ChangeLog</a></li>
<li><a href="#trunkSourceWebCoreplatformMemoryPressureHandlercpp">trunk/Source/WebCore/platform/MemoryPressureHandler.cpp</a></li>
<li><a href="#trunkSourceWebCoreplatformMemoryPressureHandlerh">trunk/Source/WebCore/platform/MemoryPressureHandler.h</a></li>
<li><a href="#trunkSourceWebCoreplatformcocoaMemoryPressureHandlerCocoamm">trunk/Source/WebCore/platform/cocoa/MemoryPressureHandlerCocoa.mm</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/ChangeLog (170972 => 170973)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/ChangeLog 2014-07-10 20:04:42 UTC (rev 170972)
+++ trunk/Source/WebCore/ChangeLog 2014-07-10 20:24:12 UTC (rev 170973)
</span><span class="lines">@@ -1,3 +1,29 @@
</span><ins>+2014-07-10 Andreas Kling <akling@apple.com>
+
+ [iOS WebKit2] Some memory pressure relief tweaks.
+ <https://webkit.org/b/134811>
+
+ Split memory pressure relief into critical and non-critical sections.
+ Non-critical relief is for clearing out things that are really not
+ essential, e.g unused font data, text measurement caches, etc.
+
+ On iOS, only flip the "WebKit is under memory pressure" flag when we
+ are under *critical* memroy pressure, rather than doing it early on
+ and gimping ourselves because other processes are too big.
+
+ Also added logging for when we transition in/out of system pressure.
+
+ Reviewed by Geoffrey Garen.
+
+ * platform/MemoryPressureHandler.cpp:
+ (WebCore::MemoryPressureHandler::releaseNoncriticalMemory):
+ (WebCore::MemoryPressureHandler::releaseCriticalMemory):
+ (WebCore::MemoryPressureHandler::releaseMemory):
+ * platform/MemoryPressureHandler.h:
+ (WebCore::MemoryPressureHandler::ReliefLogger::loggingEnabled):
+ * platform/cocoa/MemoryPressureHandlerCocoa.mm:
+ (WebCore::MemoryPressureHandler::install):
+
</ins><span class="cx"> 2014-07-10 Beth Dakin <bdakin@apple.com>
</span><span class="cx">
</span><span class="cx"> Need Setting/WKPreference that allows clients to prevent scrollbars from drawing
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformMemoryPressureHandlercpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/MemoryPressureHandler.cpp (170972 => 170973)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/MemoryPressureHandler.cpp 2014-07-10 20:04:42 UTC (rev 170972)
+++ trunk/Source/WebCore/platform/MemoryPressureHandler.cpp 2014-07-10 20:24:12 UTC (rev 170973)
</span><span class="lines">@@ -68,9 +68,33 @@
</span><span class="cx"> {
</span><span class="cx"> }
</span><span class="cx">
</span><del>-void MemoryPressureHandler::releaseMemory(bool critical)
</del><ins>+void MemoryPressureHandler::releaseNoncriticalMemory()
</ins><span class="cx"> {
</span><span class="cx"> {
</span><ins>+ ReliefLogger log("Purge inactive FontData");
+ fontCache().purgeInactiveFontData();
+ }
+
+ {
+ ReliefLogger log("Clear WidthCaches");
+ clearWidthCaches();
+ }
+
+ {
+ ReliefLogger log("Discard Selector Query Cache");
+ for (auto* document : Document::allDocuments())
+ document->clearSelectorQueryCache();
+ }
+
+ {
+ ReliefLogger log("Clearing JS string cache");
+ JSDOMWindow::commonVM().stringCache.clear();
+ }
+}
+
+void MemoryPressureHandler::releaseCriticalMemory()
+{
+ {
</ins><span class="cx"> ReliefLogger log("Empty the PageCache");
</span><span class="cx"> int savedPageCacheCapacity = pageCache()->capacity();
</span><span class="cx"> pageCache()->setCapacity(0);
</span><span class="lines">@@ -78,11 +102,6 @@
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> {
</span><del>- ReliefLogger log("Purge inactive FontData");
- fontCache().purgeInactiveFontData();
- }
-
- {
</del><span class="cx"> ReliefLogger log("Prune MemoryCache");
</span><span class="cx"> memoryCache()->pruneToPercentage(0);
</span><span class="cx"> }
</span><span class="lines">@@ -93,32 +112,24 @@
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> {
</span><del>- ReliefLogger log("Clear WidthCaches");
- clearWidthCaches();
- }
-
- {
</del><span class="cx"> ReliefLogger log("Discard StyleResolvers");
</span><span class="cx"> for (auto* document : Document::allDocuments())
</span><span class="cx"> document->clearStyleResolver();
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> {
</span><del>- ReliefLogger log("Discard Selector Query Cache");
- for (auto* document : Document::allDocuments())
- document->clearSelectorQueryCache();
- }
-
- {
</del><span class="cx"> ReliefLogger log("Discard all JIT-compiled code");
</span><span class="cx"> gcController().discardAllCompiledCode();
</span><span class="cx"> }
</span><ins>+}
</ins><span class="cx">
</span><del>- {
- ReliefLogger log("Clearing JS string cache");
- JSDOMWindow::commonVM().stringCache.clear();
- }
</del><ins>+void MemoryPressureHandler::releaseMemory(bool critical)
+{
+ releaseNoncriticalMemory();
</ins><span class="cx">
</span><ins>+ if (critical)
+ releaseCriticalMemory();
+
</ins><span class="cx"> platformReleaseMemory(critical);
</span><span class="cx">
</span><span class="cx"> {
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformMemoryPressureHandlerh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/MemoryPressureHandler.h (170972 => 170973)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/MemoryPressureHandler.h 2014-07-10 20:04:42 UTC (rev 170972)
+++ trunk/Source/WebCore/platform/MemoryPressureHandler.h 2014-07-10 20:24:12 UTC (rev 170973)
</span><span class="lines">@@ -87,6 +87,7 @@
</span><span class="cx">
</span><span class="cx"> const char* logString() const { return m_logString; }
</span><span class="cx"> static void setLoggingEnabled(bool enabled) { s_loggingEnabled = enabled; }
</span><ins>+ static bool loggingEnabled() { return s_loggingEnabled; }
</ins><span class="cx">
</span><span class="cx"> private:
</span><span class="cx"> size_t platformMemoryUsage();
</span><span class="lines">@@ -101,6 +102,9 @@
</span><span class="cx"> static void releaseMemory(bool critical);
</span><span class="cx">
</span><span class="cx"> private:
</span><ins>+ static void releaseNoncriticalMemory();
+ static void releaseCriticalMemory();
+
</ins><span class="cx"> void uninstall();
</span><span class="cx">
</span><span class="cx"> void holdOff(unsigned);
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformcocoaMemoryPressureHandlerCocoamm"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/cocoa/MemoryPressureHandlerCocoa.mm (170972 => 170973)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/cocoa/MemoryPressureHandlerCocoa.mm 2014-07-10 20:04:42 UTC (rev 170972)
+++ trunk/Source/WebCore/platform/cocoa/MemoryPressureHandlerCocoa.mm 2014-07-10 20:24:12 UTC (rev 170973)
</span><span class="lines">@@ -96,11 +96,16 @@
</span><span class="cx"> #if PLATFORM(IOS) && __IPHONE_OS_VERSION_MIN_REQUIRED >= 80000
</span><span class="cx"> unsigned long status = dispatch_source_get_data(_cache_event_source);
</span><span class="cx"> critical = status == DISPATCH_MEMORYPRESSURE_CRITICAL;
</span><ins>+ bool wasCritical = memoryPressureHandler().isUnderMemoryPressure();
+ memoryPressureHandler().setUnderMemoryPressure(critical);
</ins><span class="cx"> if (status == DISPATCH_MEMORYSTATUS_PRESSURE_NORMAL) {
</span><del>- memoryPressureHandler().setUnderMemoryPressure(false);
</del><ins>+ if (ReliefLogger::loggingEnabled())
+ NSLog(@"System is no longer under (%s) memory pressure.", wasCritical ? "critical" : "non-critical");
</ins><span class="cx"> return;
</span><span class="cx"> }
</span><del>- memoryPressureHandler().setUnderMemoryPressure(true);
</del><ins>+
+ if (ReliefLogger::loggingEnabled())
+ NSLog(@"Got memory pressure notification (%s)", critical ? "critical" : "non-critical");
</ins><span class="cx"> #endif
</span><span class="cx"> memoryPressureHandler().respondToMemoryPressure(critical);
</span><span class="cx"> });
</span></span></pre>
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