)]}'
{
  "commit": "19a78d110d7a8045aeb90d38ee8fe9743ce88c2d",
  "tree": "722c68fda81970196b84e23126739d9fe00ca0b6",
  "parents": [
    "a1a46184e34cfd0764f06a54870defa052b0a094"
  ],
  "author": {
    "name": "Peter Zijlstra",
    "email": "peterz@infradead.org",
    "time": "Mon Oct 07 11:28:51 2013 +0100"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@kernel.org",
    "time": "Wed Oct 09 12:39:56 2013 +0200"
  },
  "message": "sched/numa: Mitigate chance that same task always updates PTEs\n\nWith a trace_printk(\"working\\n\"); right after the cmpxchg in\ntask_numa_work() we can see that of a 4 thread process, its always the\nsame task winning the race and doing the protection change.\n\nThis is a problem since the task doing the protection change has a\npenalty for taking faults -- it is busy when marking the PTEs. If its\nalways the same task the -\u003enuma_faults[] get severely skewed.\n\nAvoid this by delaying the task doing the protection change such that\nit is unlikely to win the privilege again.\n\nBefore:\n\nroot@interlagos:~# grep \"thread 0/.*working\" /debug/tracing/trace | tail -15\n      thread 0/0-3232  [022] ....   212.787402: task_numa_work: working\n      thread 0/0-3232  [022] ....   212.888473: task_numa_work: working\n      thread 0/0-3232  [022] ....   212.989538: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.090602: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.191667: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.292734: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.393804: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.494869: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.596937: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.699000: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.801067: task_numa_work: working\n      thread 0/0-3232  [022] ....   213.903155: task_numa_work: working\n      thread 0/0-3232  [022] ....   214.005201: task_numa_work: working\n      thread 0/0-3232  [022] ....   214.107266: task_numa_work: working\n      thread 0/0-3232  [022] ....   214.209342: task_numa_work: working\n\nAfter:\n\nroot@interlagos:~# grep \"thread 0/.*working\" /debug/tracing/trace | tail -15\n      thread 0/0-3253  [005] ....   136.865051: task_numa_work: working\n      thread 0/2-3255  [026] ....   136.965134: task_numa_work: working\n      thread 0/3-3256  [024] ....   137.065217: task_numa_work: working\n      thread 0/3-3256  [024] ....   137.165302: task_numa_work: working\n      thread 0/3-3256  [024] ....   137.265382: task_numa_work: working\n      thread 0/0-3253  [004] ....   137.366465: task_numa_work: working\n      thread 0/2-3255  [026] ....   137.466549: task_numa_work: working\n      thread 0/0-3253  [004] ....   137.566629: task_numa_work: working\n      thread 0/0-3253  [004] ....   137.666711: task_numa_work: working\n      thread 0/1-3254  [028] ....   137.766799: task_numa_work: working\n      thread 0/0-3253  [004] ....   137.866876: task_numa_work: working\n      thread 0/2-3255  [026] ....   137.966960: task_numa_work: working\n      thread 0/1-3254  [028] ....   138.067041: task_numa_work: working\n      thread 0/2-3255  [026] ....   138.167123: task_numa_work: working\n      thread 0/3-3256  [024] ....   138.267207: task_numa_work: working\n\nSigned-off-by: Peter Zijlstra \u003cpeterz@infradead.org\u003e\nSigned-off-by: Mel Gorman \u003cmgorman@suse.de\u003e\nReviewed-by: Rik van Riel \u003criel@redhat.com\u003e\nCc: Andrea Arcangeli \u003caarcange@redhat.com\u003e\nCc: Johannes Weiner \u003channes@cmpxchg.org\u003e\nCc: Srikar Dronamraju \u003csrikar@linux.vnet.ibm.com\u003e\nLink: http://lkml.kernel.org/r/1381141781-10992-14-git-send-email-mgorman@suse.de\nSigned-off-by: Ingo Molnar \u003cmingo@kernel.org\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "817cd7bfd517a250bffe55af9a1c9b8451f66e8d",
      "old_mode": 33188,
      "old_path": "kernel/sched/fair.c",
      "new_id": "573d815e80afaa391054352496aba6d3ce68ca87",
      "new_mode": 33188,
      "new_path": "kernel/sched/fair.c"
    }
  ]
}