[tracing] Add sqlite memory statistics to tracing.

sql/sql_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 "sql/sql_memory_dump_provider.h"
+
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "third_party/sqlite/sqlite3.h"
+
+namespace sql {
+
+// static
+SqlMemoryDumpProvider* SqlMemoryDumpProvider::GetInstance() {
+  return base::Singleton<
+      SqlMemoryDumpProvider,
+      base::LeakySingletonTraits<SqlMemoryDumpProvider>>::get();
+}
+
+SqlMemoryDumpProvider::SqlMemoryDumpProvider() {}
+
+SqlMemoryDumpProvider::~SqlMemoryDumpProvider() {}
+
+bool SqlMemoryDumpProvider::OnMemoryDump(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  base::trace_event::MemoryAllocatorDump* dump =
+      pmd->CreateAllocatorDump("sqlite");
+  dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  sqlite3_memory_used());
+  dump->AddScalar("malloc_high_wmark_size",
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  sqlite3_memory_highwater(1 /*resetFlag */));

[Scott Hess - ex-Googler, 2015/10/07 23:08:57]

sqlite3_memory_used() is literally sqlite3_status(SQLITE_STATUS_MEMORY_USED,
...) discarding the highwater mark, and vice versau for _highwater().  Since
you're already doing sqlite3_status() for malloc count below, for consistency
this could/should probably use sqlite3_status also.

[ssid, 2015/10/08 16:53:59]

I see. I thought getting them separately was faster for some reason. Changed it.

+
+  int status;
+  int dummy_high_water = -1;
+  int malloc_count = -1;
+  status = sqlite3_status(SQLITE_STATUS_MALLOC_COUNT, &malloc_count,
+                          &dummy_high_water, 0 /* resetFlag */);
+  if (status == SQLITE_OK) {
+    dump->AddScalar("malloc_count",
+                    base::trace_event::MemoryAllocatorDump::kUnitsObjects,
+                    malloc_count);
+  }
+
+  const char* system_allocator_name =
+      base::trace_event::MemoryDumpManager::GetInstance()
+          ->system_allocator_pool_name();
+  if (system_allocator_name) {
+    pmd->AddSuballocation(dump->guid(), system_allocator_name);
+  }
+  return true;
+}
+
+}  // namespace sql