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 56 matching lines @@
 
 base::trace_event::MemoryAllocatorDump*
 DiscardableSharedMemoryHeap::ScopedMemorySegment::CreateMemoryAllocatorDump(
     Span* span,
     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->shared_memory()->mapped_size()));

[reveman, 2015/08/26 15:56:18]

hm, mapped_size is the total size of the segment but we're creating a dump just
for the span, right? Should this not be "span->length() * block_size" ?

[ssid, 2015/08/26 16:00:35]

Ah yes, I got confused here because of the host side. Thanks

 
-  pmd->AddSuballocation(dump->guid(),
-                        base::StringPrintf("discardable/segment_%d", id_));
+  pmd->AddSuballocation(
+      dump->guid(),
+      base::StringPrintf("discardable/segment_%d/allocated_objects", id_));
   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 344 matching lines @@
   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);
 }
 
 }  // namespace content