Oilpan: Split completeSweep() in idle tasks into chunks

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index 88496aa7058904784e7c463207761b7c1c73e9d0..3ce579b39a7b66120abd3b81235ef8e3516cf6f9 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -609,31 +609,49 @@ Address BaseHeap::lazySweep(size_t allocationSize, size_t gcInfoIndex)
     return result;
 }
 
-void BaseHeap::completeSweep()
+void BaseHeap::sweepUnsweptPage()
+{
+    BasePage* page = m_firstUnsweptPage;
+    if (page->isEmpty()) {
+        page->unlink(&m_firstUnsweptPage);
+        page->removeFromHeap();
+    } else {
+        // Sweep a page and move the page from m_firstUnsweptPages to
+        // m_firstPages.
+        page->sweep();
+        page->unlink(&m_firstUnsweptPage);
+        page->link(&m_firstPage);
+        page->markAsSwept();
+    }
+}
+
+bool BaseHeap::lazySweepWithDeadline(double deadlineSeconds)
 {
     RELEASE_ASSERT(threadState()->isSweepingInProgress());
     ASSERT(threadState()->sweepForbidden());
 
-    if (threadState()->isMainThread())
-        ScriptForbiddenScope::enter();
-
+    int pageCount = 1;
     while (m_firstUnsweptPage) {
-        BasePage* page = m_firstUnsweptPage;
-        if (page->isEmpty()) {
-            page->unlink(&m_firstUnsweptPage);
-            page->removeFromHeap();
-        } else {
-            // Sweep a page and move the page from m_firstUnsweptPages to
-            // m_firstPages.
-            page->sweep();
-            page->unlink(&m_firstUnsweptPage);
-            page->link(&m_firstPage);
-            page->markAsSwept();
+        sweepUnsweptPage();
+        // Check the deadline every time we sweep 10 page.
+        if (pageCount % 10 == 0) {

[kouhei (in TOK), 2015/03/31 11:42:07]

Why 10?

[haraken, 2015/03/31 12:46:58]

I thought it might be heavy to call
Platform::current()->monotonicallyIncreasingTime() at every page sweep (i.e.,
128 KB sweep or one LargeObject sweep). If the performance is OK, we can just
call it per page. Actually I'm not sure.

[Sami, 2015/03/31 12:52:00]

Might want to make this a named constant too. Also, maybe it won't happen in
practice but you could also check m_firstUnsweptPage != nullptr before
scheduling the next sweep (i.e., we ran out of time but also out of pages to
sweep).

[rmcilroy, 2015/03/31 13:01:30]

+1

[haraken, 2015/03/31 13:07:45]

Will fix.

+            if (deadlineSeconds <= Platform::current()->monotonicallyIncreasingTime()) {
+                return false;
+            }
         }
+        pageCount++;
     }
+    return true;
+}
 
-    if (threadState()->isMainThread())
-        ScriptForbiddenScope::exit();
+void BaseHeap::completeSweep()
+{
+    RELEASE_ASSERT(threadState()->isSweepingInProgress());
+    ASSERT(threadState()->sweepForbidden());
+
+    while (m_firstUnsweptPage) {

[kouhei (in TOK), 2015/03/31 11:42:07]

Nit: Unneeded {}

[haraken, 2015/03/31 12:46:58]

Nit: The coding style guide is updated and it's up to us.

+        sweepUnsweptPage();
+    }
 }
 
 NormalPageHeap::NormalPageHeap(ThreadState* state, int index)