)]}'
{
  "commit": "c71a896154119f4ca9e89d6078f5f63ad60ef199",
  "tree": "0018ea80af12d6385fd0aa5295dddefdb284eebe",
  "parents": [
    "9011262a37cb438f0fa9394b5e83840db8f9680a"
  ],
  "author": {
    "name": "Arnaldo Carvalho de Melo",
    "email": "acme@redhat.com",
    "time": "Fri Jan 23 12:06:27 2009 -0200"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@elte.hu",
    "time": "Mon Jan 26 14:40:53 2009 +0100"
  },
  "message": "blktrace: add ftrace plugin\n\nImpact: New way of using the blktrace infrastructure\n\nThis drops the requirement of userspace utilities to use the blktrace\nfacility.\n\nConfiguration is done thru sysfs, adding a \"trace\" directory to the\npartition directory where blktrace can be enabled for the associated\nrequest_queue.\n\nThe same filters present in the IOCTL interface are present as sysfs\ndevice attributes.\n\nThe /sys/block/sdX/sdXN/trace/enable file allows tracing without any\nfilters.\n\nThe other files in this directory: pid, act_mask, start_lba and end_lba\ncan be used with the same meaning as with the IOCTL interface.\n\nUsing the sysfs interface will only setup the request_queue-\u003eblk_trace\nfields, tracing will only take place when the \"blk\" tracer is selected\nvia the ftrace interface, as in the following example:\n\nTo see the trace, one can use the /d/tracing/trace file or the\n/d/tracign/trace_pipe file, with semantics defined in the ftrace\ndocumentation in Documentation/ftrace.txt.\n\n[root@f10-1 ~]# cat /t/trace\n       kjournald-305   [000]  3046.491224:   8,1    A WBS 6367 + 8 \u003c- (8,1) 6304\n       kjournald-305   [000]  3046.491227:   8,1    Q   R 6367 + 8 [kjournald]\n       kjournald-305   [000]  3046.491236:   8,1    G  RB 6367 + 8 [kjournald]\n       kjournald-305   [000]  3046.491239:   8,1    P  NS [kjournald]\n       kjournald-305   [000]  3046.491242:   8,1    I RBS 6367 + 8 [kjournald]\n       kjournald-305   [000]  3046.491251:   8,1    D  WB 6367 + 8 [kjournald]\n       kjournald-305   [000]  3046.491610:   8,1    U  WS [kjournald] 1\n          \u003cidle\u003e-0     [000]  3046.511914:   8,1    C  RS 6367 + 8 [6367]\n[root@f10-1 ~]#\n\nThe default line context (prefix) format is the one described in the ftrace\ndocumentation, with the blktrace specific bits using its existing format,\ndescribed in blkparse(8).\n\nIf one wants to have the classic blktrace formatting, this is possible by\nusing:\n\n[root@f10-1 ~]# echo blk_classic \u003e /t/trace_options\n[root@f10-1 ~]# cat /t/trace\n  8,1    0  3046.491224   305  A WBS 6367 + 8 \u003c- (8,1) 6304\n  8,1    0  3046.491227   305  Q   R 6367 + 8 [kjournald]\n  8,1    0  3046.491236   305  G  RB 6367 + 8 [kjournald]\n  8,1    0  3046.491239   305  P  NS [kjournald]\n  8,1    0  3046.491242   305  I RBS 6367 + 8 [kjournald]\n  8,1    0  3046.491251   305  D  WB 6367 + 8 [kjournald]\n  8,1    0  3046.491610   305  U  WS [kjournald] 1\n  8,1    0  3046.511914     0  C  RS 6367 + 8 [6367]\n[root@f10-1 ~]#\n\nUsing the ftrace standard format allows more flexibility, such\nas the ability of asking for backtraces via trace_options:\n\n[root@f10-1 ~]# echo noblk_classic \u003e /t/trace_options\n[root@f10-1 ~]# echo stacktrace \u003e /t/trace_options\n\n[root@f10-1 ~]# cat /t/trace\n       kjournald-305   [000]  3318.826779:   8,1    A WBS 6375 + 8 \u003c- (8,1) 6312\n       kjournald-305   [000]  3318.826782:\n \u003c\u003d submit_bio\n \u003c\u003d submit_bh\n \u003c\u003d sync_dirty_buffer\n \u003c\u003d journal_commit_transaction\n \u003c\u003d kjournald\n \u003c\u003d kthread\n \u003c\u003d child_rip\n       kjournald-305   [000]  3318.826836:   8,1    Q   R 6375 + 8 [kjournald]\n       kjournald-305   [000]  3318.826837:\n \u003c\u003d generic_make_request\n \u003c\u003d submit_bio\n \u003c\u003d submit_bh\n \u003c\u003d sync_dirty_buffer\n \u003c\u003d journal_commit_transaction\n \u003c\u003d kjournald\n \u003c\u003d kthread\n\nPlease read the ftrace documentation to use aditional, standardized\ntracing filters such as /d/tracing/trace_cpumask, etc.\n\nSee also /d/tracing/trace_mark to add comments in the trace stream,\nthat is equivalent to the /d/block/sdaN/msg interface.\n\nSigned-off-by: Arnaldo Carvalho de Melo \u003cacme@redhat.com\u003e\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "b0a2cae886dbdc4dde9a2efa99345ea2462a54b0",
      "old_mode": 33188,
      "old_path": "block/blktrace.c",
      "new_id": "630f167f82405bc5d4a5c38c2e2c6e9e2158dc8f",
      "new_mode": 33188,
      "new_path": "block/blktrace.c"
    },
    {
      "type": "modify",
      "old_id": "6d720243f5f4a29a43a7b50dd005bbff32a7b0aa",
      "old_mode": 33188,
      "old_path": "fs/partitions/check.c",
      "new_id": "01714efdc65af8bf16cf0ebbb875fcf9edc6c4a8",
      "new_mode": 33188,
      "new_path": "fs/partitions/check.c"
    },
    {
      "type": "modify",
      "old_id": "b96037d970dfcd238997f2ec2ad6440760057596",
      "old_mode": 33188,
      "old_path": "kernel/trace/trace.h",
      "new_id": "e603a291134bdbff476bac1bb2c3713662a1b99b",
      "new_mode": 33188,
      "new_path": "kernel/trace/trace.h"
    }
  ]
}