1. 21 Dec, 2009 4 commits
  2. 15 Dec, 2009 1 commit
  3. 10 Dec, 2009 2 commits
    • Vivek Goyal's avatar
      Fix a CFQ crash in "for-2.6.33" branch of block tree · 82bbbf28
      Vivek Goyal authored
      I think my previous patch introduced a bug which can lead to CFQ hitting
      BUG_ON().
      
      The offending commit in for-2.6.33 branch is.
      
      commit 7667aa06
      Author: Vivek Goyal <vgoyal@redhat.com>
      Date:   Tue Dec 8 17:52:58 2009 -0500
      
          cfq-iosched: Take care of corner cases of group losing share due to deletion
      
      While doing some stress testing on my box, I enountered following.
      
      login: [ 3165.148841] BUG: scheduling while
      atomic: swapper/0/0x10000100
      [ 3165.149821] Modules linked in: cfq_iosched dm_multipath qla2xxx igb
      scsi_transport_fc dm_snapshot [last unloaded: scsi_wait_scan]
      [ 3165.149821] Pid: 0, comm: swapper Not tainted
      2.6.32-block-for-33-merged-new #3
      [ 3165.149821] Call Trace:
      [ 3165.149821]  <IRQ>  [<ffffffff8103fab8>] __schedule_bug+0x5c/0x60
      [ 3165.149821]  [<ffffffff8103afd7>] ? __wake_up+0x44/0x4d
      [ 3165.149821]  [<ffffffff8153a979>] schedule+0xe3/0x7bc
      [ 3165.149821]  [<ffffffff8103a796>] ? cpumask_next+0x1d/0x1f
      [ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
      [cfq_iosched]
      [ 3165.149821]  [<ffffffff810422d8>] __cond_resched+0x2a/0x35
      [ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
      [cfq_iosched]
      [ 3165.149821]  [<ffffffff8153b1ee>] _cond_resched+0x2c/0x37
      [ 3165.149821]  [<ffffffff8100e2db>] is_valid_bugaddr+0x16/0x2f
      [ 3165.149821]  [<ffffffff811e4161>] report_bug+0x18/0xac
      [ 3165.149821]  [<ffffffff8100f1fc>] die+0x39/0x63
      [ 3165.149821]  [<ffffffff8153cde1>] do_trap+0x11a/0x129
      [ 3165.149821]  [<ffffffff8100d470>] do_invalid_op+0x96/0x9f
      [ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
      [cfq_iosched]
      [ 3165.149821]  [<ffffffff81034b4d>] ? enqueue_task+0x5c/0x67
      [ 3165.149821]  [<ffffffff8103ae83>] ? task_rq_unlock+0x11/0x13
      [ 3165.149821]  [<ffffffff81041aae>] ? try_to_wake_up+0x292/0x2a4
      [ 3165.149821]  [<ffffffff8100c935>] invalid_op+0x15/0x20
      [ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
      [cfq_iosched]
      [ 3165.149821]  [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f
      [ 3165.149821]  [<ffffffff811d8c2a>] blk_peek_request+0x191/0x1a7
      [ 3165.149821]  [<ffffffff811e5b8d>] ? kobject_get+0x1a/0x21
      [ 3165.149821]  [<ffffffff812c8d4c>] scsi_request_fn+0x82/0x3df
      [ 3165.149821]  [<ffffffff8110b2de>] ? bio_fs_destructor+0x15/0x17
      [ 3165.149821]  [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f
      [ 3165.149821]  [<ffffffff811d931f>] __blk_run_queue+0x42/0x71
      [ 3165.149821]  [<ffffffff811d9403>] blk_run_queue+0x26/0x3a
      [ 3165.149821]  [<ffffffff812c8761>] scsi_run_queue+0x2de/0x375
      [ 3165.149821]  [<ffffffff812b60ac>] ? put_device+0x17/0x19
      [ 3165.149821]  [<ffffffff812c92d7>] scsi_next_command+0x3b/0x4b
      [ 3165.149821]  [<ffffffff812c9b9f>] scsi_io_completion+0x1c9/0x3f5
      [ 3165.149821]  [<ffffffff812c3c36>] scsi_finish_command+0xb5/0xbe
      
      I think I have hit following BUG_ON() in cfq_dispatch_request().
      
      BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
      
      Please find attached the patch to fix it. I have done some stress testing
      with it and have not seen it happening again.
      
      o We should wait on a queue even after slice expiry only if it is empty. If
        queue is not empty then continue to expire it.
      
      o If we decide to keep the queue then make cfqq=NULL. Otherwise select_queue()
        will return a valid cfqq and cfq_dispatch_request() can hit following
        BUG_ON().
      
        BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list))
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      82bbbf28
    • Gui Jianfeng's avatar
      cfq: Remove wait_request flag when idle time is being deleted · 554554f6
      Gui Jianfeng authored
      Remove wait_request flag when idle time is being deleted, otherwise
      it'll hit this path every time when a request is enqueued.
      Signed-off-by: default avatarGui Jianfeng <guijianfeng@cn.fujitsu.com>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      554554f6
  4. 09 Dec, 2009 11 commits
  5. 08 Dec, 2009 22 commits