Implement committed physical memory stats for Linux.

src/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 193 matching lines @@
 
   return new_space_.CommittedMemory() +
       old_pointer_space_->CommittedMemory() +
       old_data_space_->CommittedMemory() +
       code_space_->CommittedMemory() +
       map_space_->CommittedMemory() +
       cell_space_->CommittedMemory() +
       lo_space_->Size();
 }
 
+
+size_t Heap::CommittedPhysicalMemory() {

[Vyacheslav Egorov (Google), 2012/09/21 14:29:07]

This function might still return a number that is not accurate. Because when you
iterate over spaces to discover V8 Pages you touch memory and thus affect its
state. You might also end up asking OS to "unswap" OS-pages (ones that back
V8-Page headers that you access) that might have been swapped out and thus end
up with a bigger RSS than RSS before you called this function.

Also consider the following case:

1) you compute CommittedPhysicalMemory for new space
2) start computing CommittedPhysicalMemory, touch some swapped pages -> OS
un-swap's them and swaps pages backing new space this makes results computed for
new space obsolete.

+  if (!HasBeenSetUp()) return 0;
+
+  return new_space_.CommittedPhysicalMemory() +
+      old_pointer_space_->CommittedPhysicalMemory() +
+      old_data_space_->CommittedPhysicalMemory() +
+      code_space_->CommittedPhysicalMemory() +
+      map_space_->CommittedPhysicalMemory() +
+      cell_space_->CommittedPhysicalMemory() +
+      lo_space_->CommittedPhysicalMemory();
+}
+
+
 intptr_t Heap::CommittedMemoryExecutable() {
   if (!HasBeenSetUp()) return 0;
 
   return isolate()->memory_allocator()->SizeExecutable();
 }
 
 
 intptr_t Heap::Available() {
   if (!HasBeenSetUp()) return 0;
 
@@ skipping 7096 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   memcpy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   memcpy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal