Reserve a dedicated arena for every construction of mmap_address_map.

third_party/tcmalloc/chromium/src/heap-profile-table.cc

Index: third_party/tcmalloc/chromium/src/heap-profile-table.cc
diff --git a/third_party/tcmalloc/chromium/src/heap-profile-table.cc b/third_party/tcmalloc/chromium/src/heap-profile-table.cc
index 1ef18586e4d050e6e0d1ded2b5ca2df256c058be..83ae150f255d3bddf9a7b4e589bbd78777ee649f 100644
--- a/third_party/tcmalloc/chromium/src/heap-profile-table.cc
+++ b/third_party/tcmalloc/chromium/src/heap-profile-table.cc
@@ -66,6 +66,7 @@
 #include "memory_region_map.h"
 #include "base/commandlineflags.h"
 #include "base/logging.h"    // for the RawFD I/O commands
+#include "base/low_level_alloc.h"
 #include "base/sysinfo.h"
 
 using std::sort;
@@ -355,7 +356,8 @@ HeapProfileTable::MakeSortedBucketList() const {
   return list;
 }
 
-void HeapProfileTable::RefreshMMapData() {
+void HeapProfileTable::RefreshMMapData(Allocator mmap_alloc,
+                                       DeAllocator mmap_dealloc) {
   // Make the table
   static const int mmap_table_bytes = kHashTableSize * sizeof(*mmap_table_);
   if (mmap_table_ == NULL) {
@@ -364,9 +366,9 @@ void HeapProfileTable::RefreshMMapData() {
   }
   num_available_mmap_buckets_ = 0;
 
-  ClearMMapData();
-  mmap_address_map_ =
-      new(alloc_(sizeof(AllocationMap))) AllocationMap(alloc_, dealloc_);
+  ClearMMapData(mmap_dealloc);
+  mmap_address_map_ = new(mmap_alloc(sizeof(AllocationMap)))
+      AllocationMap(mmap_alloc, mmap_dealloc);
 
   MemoryRegionMap::LockHolder l;
   for (MemoryRegionMap::RegionIterator r =
@@ -387,11 +389,11 @@ void HeapProfileTable::RefreshMMapData() {
   }
 }
 
-void HeapProfileTable::ClearMMapData() {
+void HeapProfileTable::ClearMMapData(DeAllocator mmap_dealloc) {
   if (mmap_address_map_ != NULL) {

[jar (doing other things), 2012/04/04 17:38:40]

nit: early return on "== NULL" will mean you won't need curlies, and will have
less indent (and won't have to look to see what else happens).

[Dai Mikurube (NOT FULLTIME), 2012/04/05 05:19:26]

Done.

     mmap_address_map_->Iterate(ZeroBucketCountsIterator, this);
     mmap_address_map_->~AllocationMap();
-    dealloc_(mmap_address_map_);
+    mmap_dealloc(mmap_address_map_);
     mmap_address_map_ = NULL;
   }
 }