)]}'
{
  "commit": "2036d94a7b61ca5032ce90f2bda06afec0fe713e",
  "tree": "fc9f4b5ba1058e5a2fdf9ccd187766c90f5ae036",
  "parents": [
    "c5fdcec927ee31fc96e92339c3a83ac6e0725289"
  ],
  "author": {
    "name": "Paul E. McKenney",
    "email": "paul.mckenney@linaro.org",
    "time": "Mon Jan 30 17:02:47 2012 -0800"
  },
  "committer": {
    "name": "Paul E. McKenney",
    "email": "paulmck@linux.vnet.ibm.com",
    "time": "Tue Feb 21 09:06:07 2012 -0800"
  },
  "message": "rcu: Rework detection of use of RCU by offline CPUs\n\nBecause newly offlined CPUs continue executing after completing the\nCPU_DYING notifiers, they legitimately enter the scheduler and use\nRCU while appearing to be offline.  This calls for a more sophisticated\napproach as follows:\n\n1.\tRCU marks the CPU online during the CPU_UP_PREPARE phase.\n\n2.\tRCU marks the CPU offline during the CPU_DEAD phase.\n\n3.\tDiagnostics regarding use of read-side RCU by offline CPUs use\n\tRCU\u0027s accounting rather than the cpu_online_map.  (Note that\n\t__call_rcu() still uses cpu_online_map to detect illegal\n\tinvocations within CPU_DYING notifiers.)\n\n4.\tOffline CPUs are prevented from hanging the system by\n\tforce_quiescent_state(), which pays attention to cpu_online_map.\n\tSome additional work (in a later commit) will be needed to\n\tguarantee that force_quiescent_state() waits a full jiffy before\n\tassuming that a CPU is offline, for example, when called from\n\tidle entry.  (This commit also makes the one-jiffy wait\n\texplicit, since the old-style implicit wait can now be defeated\n\tby RCU_FAST_NO_HZ and by rcutorture.)\n\nThis approach avoids the false positives encountered when attempting to\nuse more exact classification of CPU online/offline state.\n\nSigned-off-by: Paul E. McKenney \u003cpaul.mckenney@linaro.org\u003e\nSigned-off-by: Paul E. McKenney \u003cpaulmck@linux.vnet.ibm.com\u003e\n",
  "tree_diff": [
    {
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      "old_path": "Documentation/RCU/trace.txt",
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      "new_path": "Documentation/RCU/trace.txt"
    },
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      "old_path": "kernel/rcutree.c",
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      "old_path": "kernel/rcutree_plugin.h",
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    },
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}