Adding v8_isolate_memory_dump_provider.

gin/v8_isolate_memory_dump_provider.cc

+// Copyright 2015 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 "gin/v8_isolate_memory_dump_provider.h"
+
+#include "base/message_loop/message_loop.h"
+#include "base/strings/stringprintf.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "gin/public/isolate_holder.h"
+#include "v8/include/v8.h"
+
+namespace gin {
+
+namespace {
+const char kRootDumpName[] = "v8";
+const char kIsolateDumpName[] = "isolate";
+const char kAvailableSizeAttribute[] = "available_size_in_bytes";
+}  // namespace
+
+V8IsolateMemoryDumpProvider::V8IsolateMemoryDumpProvider(
+    IsolateHolder* isolate_holder)
+    : isolate_holder_(isolate_holder) {
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      this, base::ThreadTaskRunnerHandle::Get());
+}
+
+V8IsolateMemoryDumpProvider::~V8IsolateMemoryDumpProvider() {
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);
+}
+
+// Called at trace dump point time. Creates a snapshot with the memory counters
+// for the current isolate.
+bool V8IsolateMemoryDumpProvider::OnMemoryDump(
+    base::trace_event::ProcessMemoryDump* pmd) {
+  if (isolate_holder_->access_mode() == IsolateHolder::kUseLocker) {
+    v8::Locker locked(isolate_holder_->isolate());
+    DumpMemoryStatistics(pmd);
+  } else {
+    DumpMemoryStatistics(pmd);
+  }
+  return true;
+}
+
+void V8IsolateMemoryDumpProvider::DumpMemoryStatistics(
+    base::trace_event::ProcessMemoryDump* pmd) {
+  v8::HeapStatistics heap_statistics;
+  isolate_holder_->isolate()->GetHeapStatistics(&heap_statistics);
+
+  size_t known_spaces_used_size = 0;
+  size_t known_spaces_size = 0;
+  size_t number_of_spaces = isolate_holder_->isolate()->NumberOfHeapSpaces();
+  for (size_t space = 0; space < number_of_spaces; space++) {
+    v8::HeapSpaceStatistics space_statistics;
+    isolate_holder_->isolate()->GetHeapSpaceStatistics(&space_statistics,
+                                                       space);
+    const size_t space_size = space_statistics.space_size();
+    const size_t space_used_size = space_statistics.space_used_size();
+
+    known_spaces_size += space_size;
+    known_spaces_used_size += space_used_size;
+
+    std::string allocator_name = base::StringPrintf(
+        "%s/%s_%p/%s", kRootDumpName, kIsolateDumpName,

[Primiano Tucci (use gerrit), 2015/05/08 08:50:34]

I just realized that, in light of our offline conversations, this should be 
"%s/%s_%p/heap/%s", i.e. "v8/isolate_0x1234/heaps/xxx_space"?
So that this is going to be future-proof with the extended objects stats you are
going to introduce.

[ssid, 2015/05/08 09:46:54]

Done.

+        isolate_holder_->isolate(), space_statistics.space_name());
+    base::trace_event::MemoryAllocatorDump* space_dump =
+        pmd->CreateAllocatorDump(allocator_name);
+    space_dump->AddScalar(
+        base::trace_event::MemoryAllocatorDump::kNameOuterSize,
+        base::trace_event::MemoryAllocatorDump::kUnitsBytes, space_size);
+
+    // TODO(ssid): Fix crbug.com/481504 to get the objects count of live objects
+    // after the last GC.
+    space_dump->AddScalar(
+        base::trace_event::MemoryAllocatorDump::kNameInnerSize,
+        base::trace_event::MemoryAllocatorDump::kUnitsBytes, space_used_size);
+    space_dump->AddScalar(kAvailableSizeAttribute,
+                          base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                          space_statistics.space_available_size());
+  }
+  // Compute the rest of the memory, not accounted by the spaces above.
+  std::string allocator_name =
+      base::StringPrintf("%s/%s_%p/%s", kRootDumpName, kIsolateDumpName,
+                         isolate_holder_->isolate(), "other_spaces");
+  base::trace_event::MemoryAllocatorDump* other_spaces_dump =
+      pmd->CreateAllocatorDump(allocator_name);
+  other_spaces_dump->AddScalar(
+      base::trace_event::MemoryAllocatorDump::kNameOuterSize,
+      base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+      heap_statistics.total_heap_size() - known_spaces_size);
+  other_spaces_dump->AddScalar(
+      base::trace_event::MemoryAllocatorDump::kNameInnerSize,
+      base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+      heap_statistics.used_heap_size() - known_spaces_used_size);
+
+  // TODO(ssid): Fix crbug.com/481504 to get the total available size of the
+  // heap.
+  other_spaces_dump->AddScalar(
+      kAvailableSizeAttribute,
+      base::trace_event::MemoryAllocatorDump::kUnitsBytes, 0);
+}
+
+}  // namespace gin