)]}'
{
  "commit": "bcff25fc8aa47a13faff8b4b992589813f7b450a",
  "tree": "ae93e2b8ba1417bf6327f79154c69b9afc8328bb",
  "parents": [
    "fcc5c22218a18509a7412bf074fc9a7a5d874a8a"
  ],
  "author": {
    "name": "Jan Kara",
    "email": "jack@suse.cz",
    "time": "Fri Jul 01 13:31:25 2011 -0600"
  },
  "committer": {
    "name": "Wu Fengguang",
    "email": "fengguang.wu@intel.com",
    "time": "Sun Jul 24 10:51:52 2011 +0800"
  },
  "message": "mm: properly reflect task dirty limits in dirty_exceeded logic\n\nWe set bdi-\u003edirty_exceeded (and thus ratelimiting code starts to\ncall balance_dirty_pages() every 8 pages) when a per-bdi limit is\nexceeded or global limit is exceeded. But per-bdi limit also depends\non the task. Thus different tasks reach the limit on that bdi at\ndifferent levels of dirty pages. The result is that with current code\nbdi-\u003edirty_exceeded ping-ponged between 1 and 0 depending on which task\njust got into balance_dirty_pages().\n\nWe fix the issue by clearing bdi-\u003edirty_exceeded only when per-bdi amount\nof dirty pages drops below the threshold (7/8 * bdi_dirty_limit) where task\nlimits already do not have any influence.\n\nImpact:  The end result is, the dirty pages are kept more tightly under\ncontrol, with the average number slightly lowered than before.  This\nreduces the risk to throttle light dirtiers and hence more responsive.\nHowever it may add overheads by enforcing balance_dirty_pages() calls\non every 8 pages when there are 2+ heavy dirtiers.\n\nCC: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nCC: Christoph Hellwig \u003chch@infradead.org\u003e\nCC: Dave Chinner \u003cdavid@fromorbit.com\u003e\nCC: Peter Zijlstra \u003ca.p.zijlstra@chello.nl\u003e\nSigned-off-by: Jan Kara \u003cjack@suse.cz\u003e\nSigned-off-by: Wu Fengguang \u003cfengguang.wu@intel.com\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "f9d9f5476d58abf28176d922a65534caaf369689",
      "old_mode": 33188,
      "old_path": "mm/page-writeback.c",
      "new_id": "1d781803e629a6050c4f96231feacc182be9e5d0",
      "new_mode": 33188,
      "new_path": "mm/page-writeback.c"
    }
  ]
}