Added a special stack guard to deopt marked allocation sites.

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 527 matching lines @@
         dont_tenure_decisions++;
       }
       allocation_sites++;
       if (use_scratchpad) {
         i++;
       } else {
         list_element = site->weak_next();
       }
     }
 
-    if (trigger_deoptimization) isolate_->stack_guard()->DeoptMarkedCode();
+    if (trigger_deoptimization) {
+      isolate_->stack_guard()->DeoptMarkedAllocationSites();
+    }
 
     FlushAllocationSitesScratchpad();
 
     if (FLAG_trace_pretenuring_statistics &&
         (allocation_mementos_found > 0 ||
          tenure_decisions > 0 ||
          dont_tenure_decisions > 0)) {
       PrintF("GC: (mode, #visited allocation sites, #active allocation sites, "
              "#mementos, #tenure decisions, #donttenure decisions) "
              "(%s, %d, %d, %d, %d, %d)\n",
              use_scratchpad ? "use scratchpad" : "use list",
              allocation_sites,
              active_allocation_sites,
              allocation_mementos_found,
              tenure_decisions,
              dont_tenure_decisions);
     }
   }
 }
 
 
+void Heap::DeoptMarkedAllocationSites() {
+  // TODO(hpayer): If iterating over the alloation sites list becomes a

[mvstanton, 2014/02/17 12:10:06]

"allocation"

[Hannes Payer (out of office), 2014/02/17 12:14:43]

Done.

+  // performance issue, use a cache heap data structure instead (similar to the
+  // allocation sites scratchpad).
+  Object* list_element = allocation_sites_list();
+  while (list_element->IsAllocationSite()) {
+    AllocationSite* site = AllocationSite::cast(list_element);
+    if (site->deopt_dependent_code()) {
+      site->dependent_code()->MarkCodeForDeoptimization(
+          isolate_,
+          DependentCode::kAllocationSiteTenuringChangedGroup);
+      site->set_deopt_dependent_code(false);
+    }
+    list_element = site->weak_next();
+  }
+  Deoptimizer::DeoptimizeMarkedCode(isolate_);
+}
+
+
 void Heap::GarbageCollectionEpilogue() {
   store_buffer()->GCEpilogue();
 
   // In release mode, we only zap the from space under heap verification.
   if (Heap::ShouldZapGarbage()) {
     ZapFromSpace();
   }
 
   // Process pretenuring feedback and update allocation sites.
   ProcessPretenuringFeedback();
@@ skipping 1413 matching lines @@
 
 
 void Heap::ResetAllAllocationSitesDependentCode(PretenureFlag flag) {
   DisallowHeapAllocation no_allocation_scope;
   Object* cur = allocation_sites_list();
   bool marked = false;
   while (cur->IsAllocationSite()) {
     AllocationSite* casted = AllocationSite::cast(cur);
     if (casted->GetPretenureMode() == flag) {
       casted->ResetPretenureDecision();
-      bool got_marked = casted->dependent_code()->MarkCodeForDeoptimization(
-          isolate_,
-          DependentCode::kAllocationSiteTenuringChangedGroup);
-      if (got_marked) marked = true;
+      casted->set_deopt_dependent_code(true);
+      marked = true;
     }
     cur = casted->weak_next();
   }
-  if (marked) isolate_->stack_guard()->DeoptMarkedCode();
+  if (marked) isolate_->stack_guard()->DeoptMarkedAllocationSites();
 }
 
 
 void Heap::EvaluateOldSpaceLocalPretenuring(
     uint64_t size_of_objects_before_gc) {
   uint64_t size_of_objects_after_gc = SizeOfObjects();
   double old_generation_survival_rate =
       (static_cast<double>(size_of_objects_after_gc) * 100) /
           static_cast<double>(size_of_objects_before_gc);
 
@@ skipping 5699 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal