Revert r11835 'Unify promotion and allocation limit computation' due to V8 Splay performance regres…

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 100 matching lines @@
       gc_count_(0),
       remembered_unmapped_pages_index_(0),
       unflattened_strings_length_(0),
 #ifdef DEBUG
       allocation_allowed_(true),
       allocation_timeout_(0),
       disallow_allocation_failure_(false),
       debug_utils_(NULL),
 #endif  // DEBUG
       new_space_high_promotion_mode_active_(false),
-      old_gen_promotion_limit_(kMinPromotionLimit),
-      old_gen_allocation_limit_(kMinAllocationLimit),
+      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_symbol_(NULL),
       global_gc_prologue_callback_(NULL),
       global_gc_epilogue_callback_(NULL),
@@ skipping 689 matching lines @@
       // 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_ =
-        OldGenLimit(size_of_old_gen_at_last_old_space_gc_, kMinPromotionLimit);
+        OldGenPromotionLimit(size_of_old_gen_at_last_old_space_gc_);
     old_gen_allocation_limit_ =
-        OldGenLimit(size_of_old_gen_at_last_old_space_gc_, kMinAllocationLimit);
+        OldGenAllocationLimit(size_of_old_gen_at_last_old_space_gc_);
 
     old_gen_exhausted_ = false;
   } else {
     tracer_ = tracer;
     Scavenge();
     tracer_ = NULL;
 
     UpdateSurvivalRateTrend(start_new_space_size);
   }
 
@@ skipping 6322 matching lines @@
   } else {
     p ^= 0x1d1ed & (Page::kPageSize - 1);  // I died.
   }
   remembered_unmapped_pages_[remembered_unmapped_pages_index_] =
       reinterpret_cast<Address>(p);
   remembered_unmapped_pages_index_++;
   remembered_unmapped_pages_index_ %= kRememberedUnmappedPages;
 }
 
 } }  // namespace v8::internal