1 files changed, 90 insertions, 0 deletions
diff --git a/base/memory/shared_memory_tracker.h b/base/memory/shared_memory_tracker.h
new file mode 100644
index 0000000000..499b1728cb
--- /dev/null
+++ b/base/memory/shared_memory_tracker.h
@@ -0,0 +1,90 @@
+// Copyright 2017 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.
+
+#ifndef BASE_MEMORY_SHARED_MEMORY_TRACKER_H_
+#define BASE_MEMORY_SHARED_MEMORY_TRACKER_H_
+
+#include <map>
+#include <string>
+
+#include "base/memory/shared_memory.h"
+#include "base/memory/shared_memory_mapping.h"
+#include "base/synchronization/lock.h"
+#include "base/trace_event/memory_dump_provider.h"
+
+namespace base {
+
+namespace trace_event {
+class MemoryAllocatorDump;
+class MemoryAllocatorDumpGuid;
+class ProcessMemoryDump;
+}
+
+// SharedMemoryTracker tracks shared memory usage.
+class BASE_EXPORT SharedMemoryTracker : public trace_event::MemoryDumpProvider {
+ public:
+  // Returns a singleton instance.
+  static SharedMemoryTracker* GetInstance();
+
+  static std::string GetDumpNameForTracing(const UnguessableToken& id);
+
+  static trace_event::MemoryAllocatorDumpGuid GetGlobalDumpIdForTracing(
+      const UnguessableToken& id);
+
+  // Gets or creates if non-existant, a memory dump for the |shared_memory|
+  // inside the given |pmd|. Also adds the necessary edges for the dump when
+  // creating the dump.
+  static const trace_event::MemoryAllocatorDump* GetOrCreateSharedMemoryDump(
+      const SharedMemory* shared_memory,
+      trace_event::ProcessMemoryDump* pmd);
+  // We're in the middle of a refactor https://crbug.com/795291. Eventually, the
+  // first call will go away.
+  static const trace_event::MemoryAllocatorDump* GetOrCreateSharedMemoryDump(
+      const SharedMemoryMapping& shared_memory,
+      trace_event::ProcessMemoryDump* pmd);
+
+  // Records shared memory usage on valid mapping.
+  void IncrementMemoryUsage(const SharedMemory& shared_memory);
+  void IncrementMemoryUsage(const SharedMemoryMapping& mapping);
+
+  // Records shared memory usage on unmapping.
+  void DecrementMemoryUsage(const SharedMemory& shared_memory);
+  void DecrementMemoryUsage(const SharedMemoryMapping& mapping);
+
+  // Root dump name for all shared memory dumps.
+  static const char kDumpRootName[];
+
+ private:
+  SharedMemoryTracker();
+  ~SharedMemoryTracker() override;
+
+  // trace_event::MemoryDumpProvider implementation.
+  bool OnMemoryDump(const trace_event::MemoryDumpArgs& args,
+                    trace_event::ProcessMemoryDump* pmd) override;
+
+  static const trace_event::MemoryAllocatorDump*
+  GetOrCreateSharedMemoryDumpInternal(void* mapped_memory,
+                                      size_t mapped_size,
+                                      const UnguessableToken& mapped_id,
+                                      trace_event::ProcessMemoryDump* pmd);
+
+  // Information associated with each mapped address.
+  struct UsageInfo {
+    UsageInfo(size_t size, const UnguessableToken& id)
+        : mapped_size(size), mapped_id(id) {}
+
+    size_t mapped_size;
+    UnguessableToken mapped_id;
+  };
+
+  // Used to lock when |usages_| is modified or read.
+  Lock usages_lock_;
+  std::map<void*, UsageInfo> usages_;
+
+  DISALLOW_COPY_AND_ASSIGN(SharedMemoryTracker);
+};
+
+}  // namespace base
+
+#endif  // BASE_MEMORY_SHARED_MEMORY_TRACKER_H_