[heap] Add concurrency-safe refilling to compaction spaces

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 529 matching lines @@
     if (!page->SweepingCompleted()) {
       // We were not able to sweep that page, i.e., a concurrent
       // sweeper thread currently owns this page. Wait for the sweeper
       // thread to be done with this page.
       page->WaitUntilSweepingCompleted();
     }
   }
 }
 
 
+void MarkCompactCollector::SweepAndRefill(CompactionSpace* space) {
+  if (!heap()->concurrent_sweeping_enabled() || !IsSweepingCompleted()) {

[Hannes Payer (out of office), 2015/10/22 11:05:13]

Let's factor this condition out into a separate function, since it is used
somewhere else as well.

[Michael Lippautz, 2015/10/22 12:50:38]

As discussed offline, the condition we want is actually different.

+    SweepInParallel(heap()->paged_space(space->identity()), 0);
+  }
+  space->RefillFreeList();
+}
+
+
 void MarkCompactCollector::EnsureSweepingCompleted() {
   DCHECK(sweeping_in_progress_ == true);
 
   // If sweeping is not completed or not running at all, we try to complete it
   // here.
   if (!heap()->concurrent_sweeping_enabled() || !IsSweepingCompleted()) {
     SweepInParallel(heap()->paged_space(OLD_SPACE), 0);
     SweepInParallel(heap()->paged_space(CODE_SPACE), 0);
     SweepInParallel(heap()->paged_space(MAP_SPACE), 0);
   }
@@ skipping 4056 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(&rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8