)]}'
{
  "commit": "240c879f20a605346705be24253bc9fc6fa8a106",
  "tree": "85c38509483aa5f69d3dea5daa21412dd2e6aced",
  "parents": [
    "ecb256f815232b35ae8382cff36ca8ce0bbd077e"
  ],
  "author": {
    "name": "Minchan Kim",
    "email": "minchan.kim@gmail.com",
    "time": "Thu Jan 13 15:46:27 2011 -0800"
  },
  "committer": {
    "name": "Linus Torvalds",
    "email": "torvalds@linux-foundation.org",
    "time": "Thu Jan 13 17:32:38 2011 -0800"
  },
  "message": "writeback: avoid unnecessary determine_dirtyable_memory call\n\nI think determine_dirtyable_memory() is a rather costly function since it\nneed many atomic reads for gathering zone/global page state.  But when we\nuse vm_dirty_bytes \u0026\u0026 dirty_background_bytes, we don\u0027t need that costly\ncalculation.\n\nThis patch eliminates such unnecessary overhead.\n\nNOTE : newly added if condition might add overhead in normal path.\n       But it should be _really_ small because anyway we need the\n       access both vm_dirty_bytes and dirty_background_bytes so it is\n       likely to hit the cache.\n\n[akpm@linux-foundation.org: fix used-uninitialised warning]\nSigned-off-by: Minchan Kim \u003cminchan.kim@gmail.com\u003e\nCc: Wu Fengguang \u003cfengguang.wu@intel.com\u003e\nCc: Peter Zijlstra \u003ca.p.zijlstra@chello.nl\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "28763b8bdbddd9caba1478cc9e8aa205a02cf397",
      "old_mode": 33188,
      "old_path": "mm/page-writeback.c",
      "new_id": "2cb01f6ec5d019e7e431d9f18cdba6f3bde573e4",
      "new_mode": 33188,
      "new_path": "mm/page-writeback.c"
    }
  ]
}