Track how many pages trigger fallback strategies in GC

src/heap/store-buffer.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 
 #include "src/v8.h"
 
 #include "src/counters.h"
 #include "src/heap/store-buffer-inl.h"
@@ skipping 179 matching lines @@
     int old_counter = containing_chunk->store_buffer_counter();
     if (old_counter >= threshold) {
       containing_chunk->set_scan_on_scavenge(true);
       created_new_scan_on_scavenge_pages = true;
     }
     containing_chunk->set_store_buffer_counter(old_counter + 1);
     previous_chunk = containing_chunk;
   }
   if (created_new_scan_on_scavenge_pages) {
     Filter(MemoryChunk::SCAN_ON_SCAVENGE);
+    heap_->isolate()->CountUsage(
+        v8::Isolate::UseCounterFeature::kStoreBufferOverflow);
   }
   old_buffer_is_filtered_ = true;
 }
 
 
 void StoreBuffer::Filter(int flag) {
   Address* new_top = old_start_;
   MemoryChunk* previous_chunk = NULL;
   for (Address* p = old_start_; p < old_top_; p++) {
     Address addr = *p;
@@ skipping 352 matching lines @@
     }
     old_buffer_is_sorted_ = false;
     old_buffer_is_filtered_ = false;
     *old_top_++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
     DCHECK(old_top_ <= old_limit_);
   }
   heap_->isolate()->counters()->store_buffer_compactions()->Increment();
 }
 }
 }  // namespace v8::internal