[tracing] Add SkResourceCache as suballocation to avoid double counting.

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"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/memory_dump_manager.h"
 
 namespace content {
 namespace {
 
 bool IsPowerOfTwo(size_t x) {
   return (x & (x - 1)) == 0;
 }
 
 bool IsInFreeList(DiscardableSharedMemoryHeap::Span* span) {
   return span->previous() || span->next();
 }
 
+const char kDiscardableSegmentsDumpName[] = "discardable/segments";
+
 }  // namespace
 
 DiscardableSharedMemoryHeap::Span::Span(
     base::DiscardableSharedMemory* shared_memory,
     size_t start,
     size_t length)
     : shared_memory_(shared_memory), start_(start), length_(length) {
 }
 
 DiscardableSharedMemoryHeap::Span::~Span() {
@@ skipping 183 matching lines @@
 size_t DiscardableSharedMemoryHeap::GetSize() const {
   return num_blocks_ * block_size_;
 }
 
 size_t DiscardableSharedMemoryHeap::GetSizeOfFreeLists() const {
   return num_free_blocks_ * block_size_;
 }
 
 bool DiscardableSharedMemoryHeap::OnMemoryDump(
     base::trace_event::ProcessMemoryDump* pmd) {
+  CreateAllocatedObjectsDump(pmd);
   std::for_each(
       memory_segments_.begin(), memory_segments_.end(),
       [pmd](const ScopedMemorySegment* segment) {
         segment->OnMemoryDump(pmd);
       });
   return true;
 }
 
 void DiscardableSharedMemoryHeap::InsertIntoFreeList(
     scoped_ptr<DiscardableSharedMemoryHeap::Span> span) {
@@ skipping 111 matching lines @@
   size_t end = offset + size / block_size_;
   while (offset < end) {
     Span* span = spans_[offset];
     if (!IsInFreeList(span)) {
       allocated_objects_count++;
       allocated_objects_size_in_bytes += span->length_ * block_size_;
     }
     offset += span->length_;
   }
 
-  std::string segment_dump_name =
-      base::StringPrintf("discardable/segment_%d", segment_id);
+  std::string segment_dump_name = base::StringPrintf(
+      "%s/segment_%d", kDiscardableSegmentsDumpName, segment_id);
   base::trace_event::MemoryAllocatorDump* segment_dump =
       pmd->CreateAllocatorDump(segment_dump_name);
   segment_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                           base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                           static_cast<uint64_t>(size));
 
   base::trace_event::MemoryAllocatorDump* obj_dump =
       pmd->CreateAllocatorDump(segment_dump_name + "/allocated_objects");
   obj_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameObjectsCount,
                       base::trace_event::MemoryAllocatorDump::kUnitsObjects,
@@ skipping 12 matching lines @@
   base::trace_event::MemoryAllocatorDumpGuid shared_segment_guid =
       GetSegmentGUIDForTracing(tracing_process_id, segment_id);
   pmd->CreateSharedGlobalAllocatorDump(shared_segment_guid);
 
   // By creating an edge with a higher |importance| (w.r.t. browser-side dumps)
   // the tracing UI will account the effective size of the segment to the child.
   const int kImportance = 2;
   pmd->AddOwnershipEdge(segment_dump->guid(), shared_segment_guid, kImportance);
 }
 
+void DiscardableSharedMemoryHeap::CreateAllocatedObjectsDump(

[petrcermak, 2015/07/29 16:38:59]

nit: I think you should say "// static" above the function definition.

[ssid, 2015/07/29 16:57:37]

Done.

+    base::trace_event::ProcessMemoryDump* pmd) {
+  base::trace_event::MemoryAllocatorDump* objects_dump =
+      pmd->CreateAllocatorDump(
+          base::DiscardableSharedMemory::kAllocatedObjectsDumpName);
+  base::trace_event::MemoryAllocatorDump* discardable_segments_dump =
+      pmd->CreateAllocatorDump(kDiscardableSegmentsDumpName);
+
+  // The discardable memory segments will contain kDiscardableSegmentsDumpName

[petrcermak, 2015/07/29 16:38:59]

This is reversed. The dump called kDiscardableSegmentsDumpName will contain
discardable memory segments.

[ssid, 2015/07/29 16:57:37]

Done.

+  // as the root and will own any sub-allocations with kAllocatedObjectsDumpName

[petrcermak, 2015/07/29 16:38:59]

Probably "parent" or "ancestor" instead of "root" ("discardable/" is the root)
(twice).

[petrcermak, 2015/07/29 16:38:59]

s/own/be owned by/

[ssid, 2015/07/29 16:57:37]

Done.

+  // as the root.
+  pmd->AddOwnershipEdge(objects_dump->guid(),
+                        discardable_segments_dump->guid());
+}
+
 // static
 base::trace_event::MemoryAllocatorDumpGuid
 DiscardableSharedMemoryHeap::GetSegmentGUIDForTracing(uint64 tracing_process_id,
                                                       int32 segment_id) {
   return base::trace_event::MemoryAllocatorDumpGuid(base::StringPrintf(
       "discardable-x-process/%" PRIx64 "/%d", tracing_process_id, segment_id));
 }
 
 }  // namespace content