Fix the size dumped by child discardable manager for tracing.

content/common/discardable_shared_memory_heap.cc

 // Copyright 2014 The Chromium 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 "content/common/discardable_shared_memory_heap.h"
 
 #include <algorithm>
 
 #include "base/format_macros.h"
 #include "base/memory/discardable_shared_memory.h"
@@ skipping 50 matching lines @@
 }
 
 bool DiscardableSharedMemoryHeap::ScopedMemorySegment::ContainsSpan(
     Span* span) const {
   return shared_memory_ == span->shared_memory();
 }
 
 base::trace_event::MemoryAllocatorDump*
 DiscardableSharedMemoryHeap::ScopedMemorySegment::CreateMemoryAllocatorDump(
     Span* span,
+    size_t block_size,
     const char* name,
     base::trace_event::ProcessMemoryDump* pmd) const {
   DCHECK_EQ(shared_memory_, span->shared_memory());
   base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(name);
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                  static_cast<uint64_t>(span->length()));
+                  static_cast<uint64_t>(span->length() * block_size));
 
-  pmd->AddSuballocation(dump->guid(),
-                        base::StringPrintf("discardable/segment_%d", id_));
+  pmd->AddSuballocation(
+      dump->guid(),
+      base::StringPrintf("discardable/segment_%d/allocated_objects", id_));

[reveman, 2015/08/26 16:02:09]

why are you adding /allocated_objects here?

[ssid, 2015/08/26 16:05:57]

The sub-allocations are usually added under "allocated_objects". Like in the
case of malloc.

This is because the children of segment (if any in future) will not be double
counted along with these sub-allocations. But will be represented as "children
is same as allocated_objects" with ownership edge.

[reveman, 2015/08/26 16:21:04]

Ack.

   return dump;
 }
 
 void DiscardableSharedMemoryHeap::ScopedMemorySegment::OnMemoryDump(
     base::trace_event::ProcessMemoryDump* pmd) const {
   heap_->OnMemoryDump(shared_memory_.get(), size_, id_, pmd);
 }
 
 DiscardableSharedMemoryHeap::DiscardableSharedMemoryHeap(size_t block_size)
     : block_size_(block_size), num_blocks_(0), num_free_blocks_(0) {
@@ skipping 340 matching lines @@
                     base::trace_event::MemoryAllocatorDump::kUnitsBytes, 0u);
     return dump;
   }
 
   ScopedVector<ScopedMemorySegment>::const_iterator it =
       std::find_if(memory_segments_.begin(), memory_segments_.end(),
                    [span](const ScopedMemorySegment* segment) {
                      return segment->ContainsSpan(span);
                    });
   DCHECK(it != memory_segments_.end());
-  return (*it)->CreateMemoryAllocatorDump(span, name, pmd);
+  return (*it)->CreateMemoryAllocatorDump(span, block_size_, name, pmd);
 }
 
 }  // namespace content