Changeset 196104 in webkit

Timestamp:

Feb 3, 2016 7:12:23 PM (8 years ago)

Author:

akling@apple.com

Message:

[iOS] Throw away linked code when navigating to a new page.
<​https://webkit.org/b/153851>

Reviewed by Gavin Barraclough.

Source/JavaScriptCore:

Add a VM API for throwing away linked code only.

• runtime/VM.cpp:

(JSC::VM::deleteAllLinkedCode):

• runtime/VM.h:

Source/WebCore:

When navigating to a new page, tell JSC to throw out any linked code it has lying around.
Linked code is tied to a specific global object, and as we're creating a new one for the
new page, none of it is useful to us here.
In the event that the user navigates back, the cost of relinking some code will be far
lower than the memory cost of keeping all of it around.

• bindings/js/GCController.cpp:

(WebCore::GCController::deleteAllLinkedCode):

• bindings/js/GCController.h:
• loader/FrameLoader.cpp:

(WebCore::FrameLoader::commitProvisionalLoad):

Location:

trunk/Source

Files:

• JavaScriptCore/ChangeLog (modified) (1 diff)
• JavaScriptCore/runtime/VM.cpp (modified) (1 diff)
• JavaScriptCore/runtime/VM.h (modified) (1 diff)
• WebCore/ChangeLog (modified) (1 diff)
• WebCore/bindings/js/GCController.cpp (modified) (1 diff)
• WebCore/bindings/js/GCController.h (modified) (1 diff)
• WebCore/loader/FrameLoader.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-02-03  Andreas Kling  <akling@apple.com>
+
+        [iOS] Throw away linked code when navigating to a new page.
+        <https://webkit.org/b/153851>
+
+        Reviewed by Gavin Barraclough.
+
+        Add a VM API for throwing away linked code only.
+
+        * runtime/VM.cpp:
+        (JSC::VM::deleteAllLinkedCode):
+        * runtime/VM.h:
+
 2016-02-03  Michael Catanzaro  <mcatanzaro@igalia.com>
 

trunk/Source/JavaScriptCore/runtime/VM.cpp

@@ -543 +543 @@
 }
 
+void VM::deleteAllLinkedCode()
+{
+    whenIdle([this]() {
+        heap.deleteAllCodeBlocks();
+        heap.reportAbandonedObjectGraph();
+    });
+}
+
 void VM::deleteAllCode()
 {

trunk/Source/JavaScriptCore/runtime/VM.h

@@ -575 +575 @@
 
     JS_EXPORT_PRIVATE void deleteAllCode();
+    JS_EXPORT_PRIVATE void deleteAllLinkedCode();
 
     void registerWatchpointForImpureProperty(const Identifier&, Watchpoint*);

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-02-03  Andreas Kling  <akling@apple.com>
+
+        [iOS] Throw away linked code when navigating to a new page.
+        <https://webkit.org/b/153851>
+
+        Reviewed by Gavin Barraclough.
+
+        When navigating to a new page, tell JSC to throw out any linked code it has lying around.
+        Linked code is tied to a specific global object, and as we're creating a new one for the
+        new page, none of it is useful to us here.
+        In the event that the user navigates back, the cost of relinking some code will be far
+        lower than the memory cost of keeping all of it around.
+
+        * bindings/js/GCController.cpp:
+        (WebCore::GCController::deleteAllLinkedCode):
+        * bindings/js/GCController.h:
+        * loader/FrameLoader.cpp:
+        (WebCore::FrameLoader::commitProvisionalLoad):
+
 2016-02-03  Alex Christensen  <achristensen@webkit.org>
 

trunk/Source/WebCore/bindings/js/GCController.cpp

@@ -123 +123 @@
 }
 
+void GCController::deleteAllLinkedCode()
+{
+    JSLockHolder lock(JSDOMWindow::commonVM());
+    JSDOMWindow::commonVM().deleteAllLinkedCode();
+}
+
 } // namespace WebCore

trunk/Source/WebCore/bindings/js/GCController.h

@@ -47 +47 @@
     WEBCORE_EXPORT void setJavaScriptGarbageCollectorTimerEnabled(bool);
     WEBCORE_EXPORT void deleteAllCode();
+    WEBCORE_EXPORT void deleteAllLinkedCode();
 
 private:

trunk/Source/WebCore/loader/FrameLoader.cpp

@@ -67 +67 @@
 #include "FrameTree.h"
 #include "FrameView.h"
+#include "GCController.h"
 #include "HTMLAnchorElement.h"
 #include "HTMLFormElement.h"
@@ -1762 +1763 @@
         PageCache::singleton().addIfCacheable(*history().currentItem(), m_frame.page());
 
+#if PLATFORM(IOS)
+    // For top-level navigations, have JSC throw away linked code. The immediate memory savings far
+    // outweigh the cost of recompiling in the case of a future backwards navigation.
+    if (!m_frame.tree().parent())
+        GCController::singleton().deleteAllLinkedCode();
+#endif
+
     if (m_loadType != FrameLoadType::Replace)
         closeOldDataSources();