[heap] Sort sweep pages list by free memory.

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 90d252abb592a46a051864883c30c6bd44b436b3..5b76243da3e408584616d62ac4380318acc018bd 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -952,9 +952,7 @@ STATIC_ASSERT(static_cast<ObjectSpace>(1 << AllocationSpace::MAP_SPACE) ==
 
 PagedSpace::PagedSpace(Heap* heap, AllocationSpace space,
                        Executability executable)
-    : Space(heap, space, executable),
-      free_list_(this),
-      end_of_unswept_pages_(NULL) {
+    : Space(heap, space, executable), free_list_(this) {
   area_size_ = MemoryAllocator::PageAreaSize(space);
   accounting_stats_.Clear();
 
@@ -1109,8 +1107,6 @@ void PagedSpace::MergeCompactionSpace(CompactionSpace* other) {
   DCHECK(other->top() == nullptr);
   DCHECK(other->limit() == nullptr);
 
-  DCHECK(other->end_of_unswept_pages_ == nullptr);
-
   AccountCommitted(other->CommittedMemory());
 
   // Move over pages.
@@ -2851,10 +2847,13 @@ HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
     if (object != NULL) return object;
 
     // If sweeping is still in progress try to sweep pages on the main thread.
-    collector->SweepInParallel(heap()->paged_space(identity()), size_in_bytes);
-    RefillFreeList();
-    object = free_list_.Allocate(size_in_bytes);
-    if (object != nullptr) return object;
+    int max_freed = collector->SweepInParallel(heap()->paged_space(identity()),
+                                               size_in_bytes, 1);

[Hannes Payer (out of office), 2016/01/20 09:25:03]

1 should be a constant.

[Michael Lippautz, 2016/01/20 11:11:16]

Done: kMaxPagesSweptDuringSlowAllocation

+    if (max_freed >= size_in_bytes) {

[Hannes Payer (out of office), 2016/01/20 09:25:03]

If you add this case, you want to call RefillFreeList(); after SweepInParallel.

[Michael Lippautz, 2016/01/20 11:11:16]

Done. (ftr: this is to move over already freed memory, in case we need them in
following allocations)

+      RefillFreeList();
+      object = free_list_.Allocate(size_in_bytes);
+      if (object != nullptr) return object;
+    }
   }
 
   // Free list allocation failed and there is no next page.  Fail if we have