)]}'
{
  "commit": "f0bdc8cdd9a2bcc2c84ae2a1fdbff4188b354d8d",
  "tree": "6d34ecec4cfc29c6032a7b6ce1acbb61088d1787",
  "parents": [
    "575969a0dd3fe65c6556bcb8f87c42303326ea55"
  ],
  "author": {
    "name": "Vivek Goyal",
    "email": "vgoyal@redhat.com",
    "time": "Thu May 19 15:38:30 2011 -0400"
  },
  "committer": {
    "name": "Jens Axboe",
    "email": "jaxboe@fusionio.com",
    "time": "Fri May 20 20:34:53 2011 +0200"
  },
  "message": "blk-cgroup: Make cgroup stat reset path blkg-\u003elock free for dispatch stats\n\nNow dispatch stats update is lock free. But reset of these stats still\ntakes blkg-\u003estats_lock and is dependent on that. As stats are per cpu,\nwe should be able to just reset the stats on each cpu without any locks.\n(Atleast for 64bit arch).\n\nOn 32bit arch there is a small race where 64bit updates are not atomic.\nThe result of this race can be that in the presence of other writers,\none might not get 0 value after reset of a stat and might see something\nintermediate\n\nOne can write more complicated code to cover this race like sending IPI\nto other cpus to reset stats and for offline cpus, reset these directly.\n\nRight not I am not taking that path because reset_update is more of a\ndebug feature and it can happen only on 32bit arch and possibility of\nit happening is small. Will fix it if it becomes a real problem. For\nthe time being going for code simplicity.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "3622518e1c23d998e97685480951b74a5af1778c",
      "old_mode": 33188,
      "old_path": "block/blk-cgroup.c",
      "new_id": "e41cc6f2ccc1536d637b7971537d339144fb6777",
      "new_mode": 33188,
      "new_path": "block/blk-cgroup.c"
    }
  ]
}