)]}'
{
  "commit": "baaca49f415b25fdbe2a8f3c22b39929e450fbfd",
  "tree": "b152b4235fc07fe56619bd3a2e975e5ca90b8c5b",
  "parents": [
    "6f7cc11aa6c7d5002e16096c7590944daece70ed"
  ],
  "author": {
    "name": "Gautham R Shenoy",
    "email": "ego@in.ibm.com",
    "time": "Wed May 09 02:34:03 2007 -0700"
  },
  "committer": {
    "name": "Linus Torvalds",
    "email": "torvalds@woody.linux-foundation.org",
    "time": "Wed May 09 12:30:51 2007 -0700"
  },
  "message": "Define and use new events,CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE\n\nThis is an attempt to provide an alternate mechanism for postponing\na hotplug event instead of using a global mechanism like lock_cpu_hotplug.\n\nThe proposal is to add two new events namely CPU_LOCK_ACQUIRE and\nCPU_LOCK_RELEASE. The notification for these two events would be sent\nout before and after a cpu_hotplug event respectively.\n\nDuring the CPU_LOCK_ACQUIRE event, a cpu-hotplug-aware subsystem is\nsupposed to acquire any per-subsystem hotcpu mutex ( Eg. workqueue_mutex\nin kernel/workqueue.c ).\n\nDuring the CPU_LOCK_RELEASE release event the cpu-hotplug-aware subsystem\nis supposed to release the per-subsystem hotcpu mutex.\n\nThe reasons for defining new events as opposed to reusing the existing events\nlike CPU_UP_PREPARE/CPU_UP_FAILED/CPU_ONLINE for locking/unlocking of\nper-subsystem hotcpu mutexes are as follow:\n\n\t- CPU_LOCK_ACQUIRE: All hotcpu mutexes are taken before subsystems\n\tstart handling pre-hotplug events like CPU_UP_PREPARE/CPU_DOWN_PREPARE\n\tetc, thus ensuring a clean handling of these events.\n\n\t- CPU_LOCK_RELEASE: The hotcpu mutexes will be released only after\n\tall subsystems have handled post-hotplug events like CPU_DOWN_FAILED,\n\tCPU_DEAD,CPU_ONLINE etc thereby ensuring that there are no subsequent\n\tclashes amongst the interdependent subsystems after a cpu hotplugs.\n\nThis patch also uses __raw_notifier_call chain in _cpu_up to take care\nof the dependency between the two consequetive calls to\nraw_notifier_call_chain.\n\n[akpm@linux-foundation.org: fix a bug]\nSigned-off-by: Gautham R Shenoy \u003cego@in.ibm.com\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": "e34221bf8946264be061c16ee56bd57ecbb4f7f6",
      "old_mode": 33188,
      "old_path": "include/linux/notifier.h",
      "new_id": "1903e5490c04c2f7b1c818511d5264bd0f526fa3",
      "new_mode": 33188,
      "new_path": "include/linux/notifier.h"
    },
    {
      "type": "modify",
      "old_id": "36e70845cfc3b40a4cfa98b06365df480caac6f3",
      "old_mode": 33188,
      "old_path": "kernel/cpu.c",
      "new_id": "48810498b355e6e09f4751847dda77c1981929a7",
      "new_mode": 33188,
      "new_path": "kernel/cpu.c"
    }
  ]
}