Simplifying GC heuristics, deleted old generation limit factor.

Review URL: https://codereview.chromium.org/15114003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14680 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -120,7 +120,6 @@ Heap::Heap()
       new_space_high_promotion_mode_active_(false),
       old_gen_promotion_limit_(kMinimumPromotionLimit),
       old_gen_allocation_limit_(kMinimumAllocationLimit),
-      old_gen_limit_factor_(1),
       size_of_old_gen_at_last_old_space_gc_(0),
       external_allocation_limit_(0),
       amount_of_external_allocated_memory_(0),
@@ -912,26 +911,11 @@ bool Heap::PerformGarbageCollection(GarbageCollector collector,
     // Perform mark-sweep with optional compaction.
     MarkCompact(tracer);
     sweep_generation_++;
-    bool high_survival_rate_during_scavenges = IsHighSurvivalRate() &&
-        IsStableOrIncreasingSurvivalTrend();
 
     UpdateSurvivalRateTrend(start_new_space_size);
 
     size_of_old_gen_at_last_old_space_gc_ = PromotedSpaceSizeOfObjects();
 
-    if (high_survival_rate_during_scavenges &&
-        IsStableOrIncreasingSurvivalTrend()) {
-      // Stable high survival rates of young objects both during partial and
-      // full collection indicate that mutator is either building or modifying
-      // a structure with a long lifetime.
-      // In this case we aggressively raise old generation memory limits to
-      // postpone subsequent mark-sweep collection and thus trade memory
-      // space for the mutation speed.
-      old_gen_limit_factor_ = 2;
-    } else {
-      old_gen_limit_factor_ = 1;
-    }
-
     old_gen_promotion_limit_ =
         OldGenPromotionLimit(size_of_old_gen_at_last_old_space_gc_);
     old_gen_allocation_limit_ =
@@ -5895,7 +5879,6 @@ void Heap::ReportHeapStatistics(const char* title) {
          old_gen_promotion_limit_);
   PrintF("old_gen_allocation_limit_ %" V8_PTR_PREFIX "d\n",
          old_gen_allocation_limit_);
-  PrintF("old_gen_limit_factor_ %d\n", old_gen_limit_factor_);
 
   PrintF("\n");
   PrintF("Number of handles : %d\n", HandleScope::NumberOfHandles(isolate_));

src/heap.h

@@ -1571,7 +1571,6 @@ class Heap {
     intptr_t limit =
         Max(old_gen_size + old_gen_size / divisor, kMinimumPromotionLimit);
     limit += new_space_.Capacity();
-    limit *= old_gen_limit_factor_;
     intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
     return Min(limit, halfway_to_the_max);
   }
@@ -1582,7 +1581,6 @@ class Heap {
     intptr_t limit =
         Max(old_gen_size + old_gen_size / divisor, kMinimumAllocationLimit);
     limit += new_space_.Capacity();
-    limit *= old_gen_limit_factor_;
     intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
     return Min(limit, halfway_to_the_max);
   }
@@ -2002,10 +2000,6 @@ class Heap {
   // every allocation in large object space.
   intptr_t old_gen_allocation_limit_;
 
-  // Sometimes the heuristics dictate that those limits are increased.  This
-  // variable records that fact.
-  int old_gen_limit_factor_;
-
   // Used to adjust the limits that control the timing of the next GC.
   intptr_t size_of_old_gen_at_last_old_space_gc_;