Messages in this thread Patch in this message | | | Date | Tue, 19 Aug 2008 14:00:24 -0400 | From | "Michael Madore" <> | Subject | Re: INFO: task blocked for more than 120 seconds |
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> On Tue, Aug 12, 2008 at 11:47:35PM +0530, Aneesh Kumar K.V wrote: >> On Mon, Aug 11, 2008 at 11:27:12AM -0700, Randy Dunlap wrote: >> > On 2.6.27-rc2-git4 and several previous kernels, I see several >> > of these messages. E.g.: >> > >> > INFO: task kjournald:665 blocked for more than 120 seconds. >> > INFO: task stress:17797 blocked for more than 120 seconds. >> > INFO: task stress:17805 blocked for more than 120 seconds. >> > >> > >> > Has anyone tracked this down? Should I attempt to bisect it? >> > (on x86_64, SMP, 8 GB RAM) >> > >> > >> > >> > INFO: task kjournald:665 blocked for more than 120 seconds. >> > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> > kjournald D ffff88027e04be30 4592 665 2 >> > ffff88027e04bdd0 0000000000000046 ffff88027e04bd90 ffffffff8022b5f8 >> > ffff88027e703090 ffff880178c91bc0 ffff88027e7033d0 0000000178c91c08 >> > ffff88027e04bdb0 ffff88027e04be30 ffff88017eaf80f0 0000000000000246 >> > Call Trace: >> > [<ffffffff8022b5f8>] ? __wake_up_common+0x41/0x74 >> > [<ffffffff802f6eef>] journal_commit_transaction+0xe9/0xd7e >> > [<ffffffff8023db06>] ? lock_timer_base+0x26/0x4a >> > [<ffffffff80247240>] ? autoremove_wake_function+0x0/0x38 >> > [<ffffffff8023db80>] ? try_to_del_timer_sync+0x56/0x62 >> > [<ffffffff802fa388>] kjournald+0xc3/0x1fb >> > [<ffffffff80247240>] ? autoremove_wake_function+0x0/0x38 >> > [<ffffffff802fa2c5>] ? kjournald+0x0/0x1fb >> > [<ffffffff80247107>] kthread+0x49/0x76 >> > [<ffffffff8020ce39>] child_rip+0xa/0x11 >> > [<ffffffff802470be>] ? kthread+0x0/0x76 >> > [<ffffffff8020ce2f>] ? child_rip+0x0/0x11 >> > >> > INFO: task stress:17797 blocked for more than 120 seconds. >> > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> > stress D ffff88017eaf8024 5088 17797 17795 >> > ffff8801f4055cd8 0000000000000082 0000000000000086 ffff88027e04bec0 >> > ffff880178c93090 ffff88017faf75f0 ffff880178c933d0 0000000300000001 >> > 0000000000000292 ffff8801f4055ce8 ffff88017eaf80a8 0000000000000246 >> > Call Trace: >> > [<ffffffff802f9c04>] log_wait_commit+0xa4/0xf4 >> > [<ffffffff80247240>] ? autoremove_wake_function+0x0/0x38 >> > [<ffffffff802f5798>] journal_stop+0x17c/0x1a9 >> > [<ffffffff802f5fe6>] journal_force_commit+0x23/0x25 >> > [<ffffffff802eee53>] ext3_force_commit+0x26/0x28 >> > [<ffffffff802e91d2>] ext3_write_inode+0x39/0x3f >> > [<ffffffff802b58cf>] __writeback_single_inode+0x180/0x284 >> > [<ffffffff80247278>] ? wake_bit_function+0x0/0x2a >> > [<ffffffff802b5db1>] generic_sync_sb_inodes+0x1c3/0x29e >> > [<ffffffff802b5e95>] sync_sb_inodes+0x9/0xb >> > [<ffffffff802b5f2c>] sync_inodes_sb+0x95/0x9c >> > [<ffffffff802b5f95>] __sync_inodes+0x62/0xaf >> > [<ffffffff802b6010>] sync_inodes+0x2e/0x33 >> > [<ffffffff802b8908>] do_sync+0x34/0x59 >> > [<ffffffff802b893b>] sys_sync+0xe/0x13 >> > [<ffffffff8020beeb>] system_call_fastpath+0x16/0x1b >> > >> >> Committing a transaction would means writing rest of the meta-data in >> the transaction. And that would imply forcing most of the buffer_heads >> to disk in ordered mode. This can result a lot of seeks and make take >> more thatn 120 seconds. > > > Both Randy and Greg reported getting this for 2.6.27-rc but not > for 2.6.26. > > Why are people getting such messages for 2.6.27-rc but not for 2.6.26?
Hi,
I have reported getting these messages on 2.6.26:
http://marc.info/?l=linux-kernel&m=121796211813099&w=2
In addition to the system mentioned in that posting, I have just reproduced it by stress testing a system with 2 Opteron processors, 2GB of RAM and 2 SATA disks.
Backing out this patch seems to help:
commit cc19747977824ece6aa1c56a29e974fef5ec2b32 Author: Jens Axboe <jens.axboe@oracle.com> Date: Fri Apr 20 20:45:39 2007 +0200
cfq-iosched: tighten queue request overlap condition
For tagged devices, allow overlap of requests if the idle window isn't enabled on the current active queue.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index a8237be..e859b49 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -989,7 +989,8 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) * flight or is idling for a new request, allow either of these * conditions to happen (or time out) before selecting a new queue. */ - if (cfqq->dispatched || timer_pending(&cfqd->idle_slice_timer)) { + if (timer_pending(&cfqd->idle_slice_timer) || + (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { cfqq = NULL; goto keep_queue; }
Mike Madore
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