[heap] Parallel newspace evacuation, semispace copy, and compaction \o/

src/heap/spaces.cc

 // Copyright 2011 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/spaces.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/heap/slots-buffer.h"
@@ skipping 2819 matching lines @@
   MarkCompactCollector* collector = heap()->mark_compact_collector();
   if (collector->sweeping_in_progress()) {
     collector->SweepAndRefill(this);
     return free_list_.Allocate(size_in_bytes);
   }
   return nullptr;
 }
 
 
 HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
+  const int kMaxPagesToSweep = 10;
   // Allocation in this space has failed.
-
+  HeapObject* object = nullptr;
   MarkCompactCollector* collector = heap()->mark_compact_collector();
   // Sweeping is still in progress.
   if (collector->sweeping_in_progress()) {
     // First try to refill the free-list, concurrent sweeper threads
     // may have freed some objects in the meantime.
     RefillFreeList();
+    // Retry the free list allocation.
+    object = free_list_.Allocate(size_in_bytes);
+    if (object != nullptr) return object;
 
-    // Retry the free list allocation.
-    HeapObject* object = free_list_.Allocate(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);
+    // If sweeping is still in progress and we are currently not compacting
+    // try to sweep pages on the main thread.
+    collector->SweepInParallel(heap()->paged_space(identity()), size_in_bytes,
+                               kMaxPagesToSweep);
     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
   // hit the old generation size limit that should cause a garbage
   // collection.
   if (!heap()->always_allocate() &&
       heap()->OldGenerationAllocationLimitReached()) {
     // If sweeper threads are active, wait for them at that point and steal
     // elements form their free-lists.
-    HeapObject* object = SweepAndRetryAllocation(size_in_bytes);
-    return object;
+    return SweepAndRetryAllocation(size_in_bytes);
   }
 
   // Try to expand the space and allocate in the new next page.
   if (Expand()) {
     DCHECK((CountTotalPages() > 1) ||
            (size_in_bytes <= free_list_.Available()));
     return free_list_.Allocate(size_in_bytes);
   }
 
   // If sweeper threads are active, wait for them at that point and steal
@@ skipping 484 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8