Expose memory allocator internal stats and properties.

base/allocator/allocator_shim.cc

Index: base/allocator/allocator_shim.cc
diff --git a/base/allocator/allocator_shim.cc b/base/allocator/allocator_shim.cc
index 9d3d932d59f2e80787a62c4c2af1565bfe43a2f4..bcc84aac984b25ffad8a97e7e3c52a2cdd42cc0a 100644
--- a/base/allocator/allocator_shim.cc
+++ b/base/allocator/allocator_shim.cc
@@ -8,6 +8,7 @@
 #include "base/allocator/allocator_extension_thunks.h"
 #include "base/profiler/alternate_timer.h"
 #include "base/sysinfo.h"
+#include "jemalloc.h"
 
 // When defined, different heap allocators can be used via an environment
 // variable set before running the program.  This may reduce the amount
@@ -231,6 +232,44 @@ extern "C" intptr_t _get_heap_handle() {
   return 0;
 }
 
+static bool get_jemalloc_property_thunk(const char* name, size_t* value) {
+  jemalloc_stats_t stats;
+  jemalloc_stats(&stats);
+#define EXTRACT_JEMALLOC_PROPERTY(property) \
+  if (strcmp(name, "jemalloc." #property) == 0) \
+    return *value = stats.property, true;
+  EXTRACT_JEMALLOC_PROPERTY(narenas);
+  EXTRACT_JEMALLOC_PROPERTY(balance_threshold);
+  EXTRACT_JEMALLOC_PROPERTY(quantum);
+  EXTRACT_JEMALLOC_PROPERTY(small_max);
+  EXTRACT_JEMALLOC_PROPERTY(large_max);
+  EXTRACT_JEMALLOC_PROPERTY(chunksize);
+  EXTRACT_JEMALLOC_PROPERTY(dirty_max);
+  EXTRACT_JEMALLOC_PROPERTY(reserve_min);
+  EXTRACT_JEMALLOC_PROPERTY(reserve_max);
+  EXTRACT_JEMALLOC_PROPERTY(mapped);
+  EXTRACT_JEMALLOC_PROPERTY(committed);
+  EXTRACT_JEMALLOC_PROPERTY(allocated);
+  EXTRACT_JEMALLOC_PROPERTY(dirty);
+  EXTRACT_JEMALLOC_PROPERTY(reserve_cur);
+#undef EXTRACT_JEMALLOC_PROPERTY
+  return false;
+}
+
+static bool get_property_thunk(const char* name, size_t* value) {
+#ifdef ENABLE_DYNAMIC_ALLOCATOR_SWITCHING
+  switch (allocator) {
+    case JEMALLOC:
+      return get_jemalloc_property_thunk(name, value);
+    case WINHEAP:
+    case WINLFH:
+      // TODO(alexeif): Implement for other allocators.
+      return false;
+  }
+#endif
+  return MallocExtension::instance()->GetNumericProperty(name, value);
+}
+
 static void get_stats_thunk(char* buffer, int buffer_length) {
   MallocExtension::instance()->GetStats(buffer, buffer_length);
 }
@@ -284,6 +323,7 @@ extern "C" int _heap_init() {
         tracked_objects::TIME_SOURCE_TYPE_TCMALLOC);
   }
 
+  base::allocator::thunks::SetGetPropertyFunction(get_property_thunk);
   base::allocator::thunks::SetGetStatsFunction(get_stats_thunk);
   base::allocator::thunks::SetReleaseFreeMemoryFunction(
       release_free_memory_thunk);