Simplify old space allocation strategy.

src/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2569 matching lines @@
     int remaining =
         static_cast<int>(allocation_info_.limit() - allocation_info_.top());
     heap()->CreateFillerObjectAt(allocation_info_.top(), remaining);
 
     allocation_info_.set_top(NULL);
     allocation_info_.set_limit(NULL);
   }
 }
 
 
-bool PagedSpace::EnsureSweeperProgress(intptr_t size_in_bytes) {
-  MarkCompactCollector* collector = heap()->mark_compact_collector();
-  if (collector->AreSweeperThreadsActivated()) {
-    if (collector->IsConcurrentSweepingInProgress()) {
-      if (collector->RefillFreeLists(this) < size_in_bytes) {
-        if (!collector->sequential_sweeping()) {
-          collector->WaitUntilSweepingCompleted();
-          return true;
-        }
-      }
-      return false;
-    }
-  }
-  return true;
-}
-
-
 HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
   // Allocation in this space has failed.
 
-  // If there are unswept pages advance sweeping a bounded number of times
-  // until we find a size_in_bytes contiguous piece of memory
-  const int kMaxSweepingTries = 5;
-  bool sweeping_complete = false;
-
-  for (int i = 0; i < kMaxSweepingTries && !sweeping_complete; i++) {
-    sweeping_complete = EnsureSweeperProgress(size_in_bytes);
+  // If sweeper threads are active, try to re-fill the free-lists.
+  MarkCompactCollector* collector = heap()->mark_compact_collector();
+  if (collector->IsConcurrentSweepingInProgress()) {
+    collector->RefillFreeList(this);
 
     // Retry the free list allocation.
     HeapObject* object = free_list_.Allocate(size_in_bytes);
     if (object != NULL) 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()) {
     return NULL;
   }
 
   // Try to expand the space and allocate in the new next page.
   if (Expand()) {
     ASSERT(CountTotalPages() > 1 || size_in_bytes <= free_list_.available());
     return free_list_.Allocate(size_in_bytes);
   }
 
-  // Last ditch, sweep all the remaining pages to try to find space.
-  if (heap()->mark_compact_collector()->IsConcurrentSweepingInProgress()) {
-    heap()->mark_compact_collector()->WaitUntilSweepingCompleted();
+  // If sweeper threads are active, wait for them at that point.
+  if (collector->IsConcurrentSweepingInProgress()) {
+    collector->WaitUntilSweepingCompleted();
 
-    // Retry the free list allocation.
+    // After waiting for the sweeper threads, there may be new free-list
+    // entries.
     HeapObject* object = free_list_.Allocate(size_in_bytes);
     if (object != NULL) return object;
   }
 
   // Finally, fail.
   return NULL;
 }
 
 
 #ifdef DEBUG
@@ skipping 502 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal