ios/chrome/browser/memory/memory_wedge.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ios/chrome/browser/memory/memory_wedge.h"
   6
   7 #include <stdlib.h>
   8
   9 #include "base/logging.h"
  10
  11 namespace {
  12
  13 // Reference to the memory wedge. It is useful to:
  14 // - make sure the compiler optimizations in Release don't skip |memset| and
  15 //   really end up putting the wedge in resident memory;
  16 // - free it in tests.
  17 static void* gMemoryWedge;
  18
  19 // The number of bytes in a megabyte.
  20 const size_t kNumBytesInMB = 1024 * 1024;
  21
  22 }  // namespace
  23
  24 namespace memory_wedge {
  25
  26 void AddWedge(size_t wedge_size_in_mb) {
  27   DCHECK(!gMemoryWedge);
  28   if (wedge_size_in_mb == 0)
  29     return;
  30
  31   // Allocate a wedge and write to it to have it in resident memory.
  32   const size_t wedge_size = wedge_size_in_mb * kNumBytesInMB;
  33   gMemoryWedge = malloc(wedge_size);
  34   memset(gMemoryWedge, -1, wedge_size);
  35 }
  36
  37 void RemoveWedgeForTesting() {
  38   DCHECK(gMemoryWedge);
  39   free(gMemoryWedge);
  40   gMemoryWedge = nullptr;
  41 }
  42
  43 }  // namespace memory_wedge