Make AdjustAmountOfExternalAllocatedMemory() more robust.

Do not crash if called from a thread without V8 isolate, reset the external
memory counters in case of overflow, bump the external allocation limit.

This will allow us to track typed array allocation and deallocation in WebKit.

BUG=v8:2022,122097,42342
R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10837122

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12262 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/api.cc

@@ -5275,8 +5275,9 @@ void V8::AddImplicitReferences(Persistent<Object> parent,
 
 
 intptr_t V8::AdjustAmountOfExternalAllocatedMemory(intptr_t change_in_bytes) {
-  i::Isolate* isolate = i::Isolate::Current();
-  if (IsDeadCheck(isolate, "v8::V8::AdjustAmountOfExternalAllocatedMemory()")) {
+  i::Isolate* isolate = i::Isolate::UncheckedCurrent();
+  if (isolate == NULL || !isolate->IsInitialized() ||
+      IsDeadCheck(isolate, "v8::V8::AdjustAmountOfExternalAllocatedMemory()")) {
     return 0;
   }
   return isolate->heap()->AdjustAmountOfExternalAllocatedMemory(

src/heap-inl.h

@@ -468,10 +468,12 @@ intptr_t Heap::AdjustAmountOfExternalAllocatedMemory(
     // Avoid overflow.
     if (amount > amount_of_external_allocated_memory_) {
       amount_of_external_allocated_memory_ = amount;
+    } else {
+      // Give up and reset the counters in case of an overflow.
+      amount_of_external_allocated_memory_ = 0;
+      amount_of_external_allocated_memory_at_last_global_gc_ = 0;
     }
-    intptr_t amount_since_last_global_gc =
-        amount_of_external_allocated_memory_ -
-        amount_of_external_allocated_memory_at_last_global_gc_;
+    intptr_t amount_since_last_global_gc = PromotedExternalMemorySize();
     if (amount_since_last_global_gc > external_allocation_limit_) {
       CollectAllGarbage(kNoGCFlags, "external memory allocation limit reached");
     }
@@ -479,6 +481,10 @@ intptr_t Heap::AdjustAmountOfExternalAllocatedMemory(
     // Avoid underflow.
     if (amount >= 0) {
       amount_of_external_allocated_memory_ = amount;
+    } else {
+      // Give up and reset the counters in case of an overflow.
+      amount_of_external_allocated_memory_ = 0;
+      amount_of_external_allocated_memory_at_last_global_gc_ = 0;
     }
   }
   ASSERT(amount_of_external_allocated_memory_ >= 0);

src/heap.cc

@@ -5793,7 +5793,7 @@ bool Heap::ConfigureHeap(int max_semispace_size,
   max_semispace_size_ = RoundUpToPowerOf2(max_semispace_size_);
   reserved_semispace_size_ = RoundUpToPowerOf2(reserved_semispace_size_);
   initial_semispace_size_ = Min(initial_semispace_size_, max_semispace_size_);
-  external_allocation_limit_ = 10 * max_semispace_size_;
+  external_allocation_limit_ = 16 * max_semispace_size_;
 
   // The old generation is paged and needs at least one page for each space.
   int paged_space_count = LAST_PAGED_SPACE - FIRST_PAGED_SPACE + 1;