Changeset 180053 in webkit

Timestamp:

Feb 13, 2015, 9:38:50 AM (11 years ago)

Author:

akling@apple.com

Message:

[iOS] Refine GC behavior in response to process suspension and memory pressure.
<​https://webkit.org/b/141543>
<rdar://problem/19738024>

Reviewed by Geoffrey Garen.

Do an immediate full garbage collection when the web process is about to
be suspended (when another tab is moving to the foreground on iOS.)
This ensures that we make a best effort to reduce the process footprint
before we lose the ability to execute code.

When receiving a memory pressure warning, tell the garbage collector to
accelerate its next collection (by calling garbageCollectSoon().)
This gives us some confidence that a collection will happen within a
reasonable timeframe, but doesn't risk dooming us to a loop of endless
garbage collections.

• platform/cocoa/MemoryPressureHandlerCocoa.mm:

(WebCore::MemoryPressureHandler::platformReleaseMemory):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/cocoa/MemoryPressureHandlerCocoa.mm (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2015-02-13  Andreas Kling  <akling@apple.com>
+
+        [iOS] Refine GC behavior in response to process suspension and memory pressure.
+        <https://webkit.org/b/141543>
+        <rdar://problem/19738024>
+
+        Reviewed by Geoffrey Garen.
+
+        Do an immediate full garbage collection when the web process is about to
+        be suspended (when another tab is moving to the foreground on iOS.)
+        This ensures that we make a best effort to reduce the process footprint
+        before we lose the ability to execute code.
+
+        When receiving a memory pressure warning, tell the garbage collector to
+        accelerate its next collection (by calling garbageCollectSoon().)
+        This gives us some confidence that a collection will happen within a
+        reasonable timeframe, but doesn't risk dooming us to a loop of endless
+        garbage collections.
+
+        * platform/cocoa/MemoryPressureHandlerCocoa.mm:
+        (WebCore::MemoryPressureHandler::platformReleaseMemory):
+
 2015-02-13  Antti Koivisto  <antti@apple.com>
 

trunk/Source/WebCore/platform/cocoa/MemoryPressureHandlerCocoa.mm

@@ -62 +62 @@
 
 #if PLATFORM(IOS)
-    {
+    if (memoryPressureHandler().isUnderMemoryPressure()) {
+        gcController().garbageCollectSoon();
+    } else {
+        // If we're not under memory pressure, that means we're here due to impending process suspension.
+        // Do a full GC since this is our last chance to run any code.
         ReliefLogger log("Collecting JavaScript garbage");
         gcController().garbageCollectNow();