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      1 // Copyright 2017 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/memory/shared_memory_tracker.h"
      6 
      7 #include "base/memory/shared_memory.h"
      8 #include "base/strings/stringprintf.h"
      9 #include "base/trace_event/memory_dump_manager.h"
     10 #include "base/trace_event/process_memory_dump.h"
     11 
     12 namespace base {
     13 
     14 SharedMemoryTracker::Usage::Usage() = default;
     15 
     16 SharedMemoryTracker::Usage::Usage(const Usage& rhs) = default;
     17 
     18 SharedMemoryTracker::Usage::~Usage() = default;
     19 
     20 // static
     21 SharedMemoryTracker* SharedMemoryTracker::GetInstance() {
     22   static SharedMemoryTracker* instance = new SharedMemoryTracker;
     23   return instance;
     24 }
     25 
     26 void SharedMemoryTracker::IncrementMemoryUsage(
     27     const SharedMemory& shared_memory) {
     28   Usage usage;
     29   // |shared_memory|'s unique ID must be generated here and it'd be too late at
     30   // OnMemoryDump. An ID is generated with a SharedMemoryHandle, but the handle
     31   // might already be closed at that time. Now IncrementMemoryUsage is called
     32   // just after mmap and the handle must live then. See the discussion at
     33   // crbug.com/604726#c30.
     34   SharedMemory::UniqueId id;
     35   if (!shared_memory.GetUniqueId(&id))
     36     return;
     37   usage.unique_id = id;
     38   usage.size = shared_memory.mapped_size();
     39   AutoLock hold(usages_lock_);
     40   usages_[&shared_memory] = usage;
     41 }
     42 
     43 void SharedMemoryTracker::DecrementMemoryUsage(
     44     const SharedMemory& shared_memory) {
     45   AutoLock hold(usages_lock_);
     46   usages_.erase(&shared_memory);
     47 }
     48 
     49 bool SharedMemoryTracker::OnMemoryDump(const trace_event::MemoryDumpArgs& args,
     50                                        trace_event::ProcessMemoryDump* pmd) {
     51   std::unordered_map<SharedMemory::UniqueId, size_t, SharedMemory::UniqueIdHash>
     52       sizes;
     53   {
     54     AutoLock hold(usages_lock_);
     55     for (const auto& usage : usages_)
     56       sizes[usage.second.unique_id] += usage.second.size;
     57   }
     58   for (auto& size : sizes) {
     59     const SharedMemory::UniqueId& id = size.first;
     60     std::string dump_name = StringPrintf("%s/%lld.%lld", "shared_memory",
     61                                          static_cast<long long>(id.first),
     62                                          static_cast<long long>(id.second));
     63     auto guid = trace_event::MemoryAllocatorDumpGuid(dump_name);
     64     trace_event::MemoryAllocatorDump* local_dump =
     65         pmd->CreateAllocatorDump(dump_name);
     66     // TODO(hajimehoshi): The size is not resident size but virtual size so far.
     67     // Fix this to record resident size.
     68     local_dump->AddScalar(trace_event::MemoryAllocatorDump::kNameSize,
     69                           trace_event::MemoryAllocatorDump::kUnitsBytes,
     70                           size.second);
     71     trace_event::MemoryAllocatorDump* global_dump =
     72         pmd->CreateSharedGlobalAllocatorDump(guid);
     73     global_dump->AddScalar(trace_event::MemoryAllocatorDump::kNameSize,
     74                            trace_event::MemoryAllocatorDump::kUnitsBytes,
     75                            size.second);
     76     // TOOD(hajimehoshi): Detect which the shared memory comes from browser,
     77     // renderer or GPU process.
     78     // TODO(hajimehoshi): Shared memory reported by GPU and discardable is
     79     // currently double-counted. Add ownership edges to avoid this.
     80     pmd->AddOwnershipEdge(local_dump->guid(), global_dump->guid());
     81   }
     82   return true;
     83 }
     84 
     85 SharedMemoryTracker::SharedMemoryTracker() {
     86   trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
     87       this, "SharedMemoryTracker", nullptr);
     88 }
     89 
     90 SharedMemoryTracker::~SharedMemoryTracker() = default;
     91 
     92 }  // namespace
     93