Add support to create memory allocator dump in base::DiscardableMemory

content/common/host_discardable_shared_memory_manager.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/host_discardable_shared_memory_manager.h"
 
 #include <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/bind.h"
@@ skipping 13 matching lines @@
 #include "content/common/child_process_host_impl.h"
 #include "content/common/discardable_shared_memory_heap.h"
 #include "content/public/common/child_process_host.h"
 
 namespace content {
 namespace {
 
 class DiscardableMemoryImpl : public base::DiscardableMemory {
  public:
   DiscardableMemoryImpl(scoped_ptr<base::DiscardableSharedMemory> shared_memory,
+                        size_t size,

[reveman, 2015/08/21 18:05:24]

can we use shared_memory->mapped_size() instead?

[ssid, 2015/08/24 14:52:10]

Done.

                         const base::Closure& deleted_callback)
       : shared_memory_(shared_memory.Pass()),
+        size_(size),
         deleted_callback_(deleted_callback),
         is_locked_(true) {}
 
   ~DiscardableMemoryImpl() override {
     if (is_locked_)
       shared_memory_->Unlock(0, 0);
 
     deleted_callback_.Run();
   }
 
@@ skipping 11 matching lines @@
     DCHECK(is_locked_);
 
     shared_memory_->Unlock(0, 0);
     is_locked_ = false;
   }
   void* data() const override {
     DCHECK(is_locked_);
     return shared_memory_->memory();
   }
 
+  base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+      const char* name,
+      base::trace_event::ProcessMemoryDump* pmd) override {
+    // The memory could have been purged by the heap, but we still create a

[reveman, 2015/08/21 18:05:24]

note: there's no heap in this case

[ssid, 2015/08/24 14:52:10]

Done.

+    // dump. So, the size can be inaccurate.
+    base::trace_event::MemoryAllocatorDump* dump =
+        pmd->CreateAllocatorDump(name);
+    dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                    base::trace_event::MemoryAllocatorDump::kUnitsBytes, size_);
+    return dump;
+  }
+
  private:
   scoped_ptr<base::DiscardableSharedMemory> shared_memory_;
+  size_t size_;
   const base::Closure deleted_callback_;
   bool is_locked_;
 
   DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryImpl);
 };
 
 base::LazyInstance<HostDiscardableSharedMemoryManager>
     g_discardable_shared_memory_manager = LAZY_INSTANCE_INITIALIZER;
 
 #if defined(OS_ANDROID)
@@ skipping 61 matching lines @@
   AllocateLockedDiscardableSharedMemory(current_process_handle,
                                         ChildProcessHost::kInvalidUniqueID,
                                         size, new_id, &handle);
   CHECK(base::SharedMemory::IsHandleValid(handle));
   scoped_ptr<base::DiscardableSharedMemory> memory(
       new base::DiscardableSharedMemory(handle));
   CHECK(memory->Map(size));
   // Close file descriptor to avoid running out.
   memory->Close();
   return make_scoped_ptr(new DiscardableMemoryImpl(
-      memory.Pass(),
+      memory.Pass(), size,
       base::Bind(
           &HostDiscardableSharedMemoryManager::DeletedDiscardableSharedMemory,
           base::Unretained(this), new_id, ChildProcessHost::kInvalidUniqueID)));
 }
 
 bool HostDiscardableSharedMemoryManager::OnMemoryDump(
     const base::trace_event::MemoryDumpArgs& args,
     base::trace_event::ProcessMemoryDump* pmd) {
   base::AutoLock lock(lock_);
   for (const auto& process_entry : processes_) {
@@ skipping 295 matching lines @@
 
   enforce_memory_policy_pending_ = true;
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&HostDiscardableSharedMemoryManager::EnforceMemoryPolicy,
                  weak_ptr_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kEnforceMemoryPolicyDelayMs));
 }
 
 }  // namespace content