Try fixing virtual memory regression from new tcmalloc: use old kPageShift and kMaxSize w/ kNumClas…

third_party/tcmalloc/chromium/src/common.cc

 // Copyright (c) 2008, Google Inc.
 // 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
@@ skipping 40 matching lines @@
       n = x;
       log += shift;
     }
   }
   ASSERT(n == 1);
   return log;
 }
 
 int AlignmentForSize(size_t size) {
   int alignment = kAlignment;
-  if (size > kMaxSize) {
-    // Cap alignment at kPageSize for large sizes.
-    alignment = kPageSize;
+  if (size > 2048) {
+    // Cap alignment at 256 for large sizes.
+    alignment = 256;
   } else if (size >= 128) {
     // Space wasted due to alignment is at most 1/8, i.e., 12.5%.
     alignment = (1 << LgFloor(size)) / 8;
   } else if (size >= 16) {
     // We need an alignment of at least 16 bytes to satisfy
     // requirements for some SSE types.
     alignment = 16;
   }
-  // Maximum alignment allowed is page size alignment.
-  if (alignment > kPageSize) {
-    alignment = kPageSize;
-  }
   CHECK_CONDITION(size < 16 || alignment >= 16);
   CHECK_CONDITION((alignment & (alignment - 1)) == 0);
   return alignment;
 }
 
 int SizeMap::NumMoveSize(size_t size) {
   if (size == 0) return 0;
   // Use approx 64k transfers between thread and central caches.
   int num = static_cast<int>(64.0 * 1024.0 / size);
   if (num < 2) num = 2;
@@ skipping 121 matching lines @@
   return result;
 }
 
 uint64_t metadata_system_bytes() { return metadata_system_bytes_; }
 
 void increment_metadata_system_bytes(size_t bytes) {
   metadata_system_bytes_ += bytes;
 }
 
 }  // namespace tcmalloc