Simplifying GC heuristics, deleted old generation limit factor.

src/heap.cc

 // Copyright 2012 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 102 matching lines @@
       remembered_unmapped_pages_index_(0),
       unflattened_strings_length_(0),
 #ifdef DEBUG
       allocation_allowed_(true),
       allocation_timeout_(0),
       disallow_allocation_failure_(false),
 #endif  // DEBUG
       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),
       amount_of_external_allocated_memory_at_last_global_gc_(0),
       old_gen_exhausted_(false),
       store_buffer_rebuilder_(store_buffer()),
       hidden_string_(NULL),
       global_gc_prologue_callback_(NULL),
       global_gc_epilogue_callback_(NULL),
       gc_safe_size_of_old_object_(NULL),
@@ skipping 771 matching lines @@
     // We speed up the incremental marker if it is running so that it
     // does not fall behind the rate of promotion, which would cause a
     // constantly growing old space.
     incremental_marking()->NotifyOfHighPromotionRate();
   }
 
   if (collector == MARK_COMPACTOR) {
     // 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_ =
         OldGenAllocationLimit(size_of_old_gen_at_last_old_space_gc_);
 
     old_gen_exhausted_ = false;
   } else {
     tracer_ = tracer;
     Scavenge();
     tracer_ = NULL;
@@ skipping 4943 matching lines @@
 // populated (via a call to CollectStatistics or else as a side effect of a
 // just-completed scavenge collection).
 void Heap::ReportHeapStatistics(const char* title) {
   USE(title);
   PrintF(">>>>>> =============== %s (%d) =============== >>>>>>\n",
          title, gc_count_);
   PrintF("old_gen_promotion_limit_ %" V8_PTR_PREFIX "d\n",
          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_));
   isolate_->global_handles()->PrintStats();
   PrintF("\n");
 
   PrintF("Heap statistics : ");
   isolate_->memory_allocator()->ReportStatistics();
   PrintF("To space : ");
   new_space_.ReportStatistics();
@@ skipping 1967 matching lines @@
   if (FLAG_parallel_recompilation) {
     heap_->relocation_mutex_->Lock();
 #ifdef DEBUG
     heap_->relocation_mutex_locked_by_optimizer_thread_ =
         heap_->isolate()->optimizing_compiler_thread()->IsOptimizerThread();
 #endif  // DEBUG
   }
 }
 
 } }  // namespace v8::internal