On Wed 29-03-17 13:14:42, Ilya Dryomov wrote: > On Wed, Mar 29, 2017 at 1:05 PM, Brian Foster <bfoster@xxxxxxxxxx> wrote: > > On Wed, Mar 29, 2017 at 12:41:26PM +0200, Michal Hocko wrote: > >> [CC xfs guys] > >> > >> On Wed 29-03-17 11:21:44, Ilya Dryomov wrote: > >> [...] > >> > This is a set of stack traces from http://tracker.ceph.com/issues/19309 > >> > (linked in the changelog): > >> > > >> > Workqueue: ceph-msgr con_work [libceph] > >> > ffff8810871cb018 0000000000000046 0000000000000000 ffff881085d40000 > >> > 0000000000012b00 ffff881025cad428 ffff8810871cbfd8 0000000000012b00 > >> > ffff880102fc1000 ffff881085d40000 ffff8810871cb038 ffff8810871cb148 > >> > Call Trace: > >> > [<ffffffff816dd629>] schedule+0x29/0x70 > >> > [<ffffffff816e066d>] schedule_timeout+0x1bd/0x200 > >> > [<ffffffff81093ffc>] ? ttwu_do_wakeup+0x2c/0x120 > >> > [<ffffffff81094266>] ? ttwu_do_activate.constprop.135+0x66/0x70 > >> > [<ffffffff816deb5f>] wait_for_completion+0xbf/0x180 > >> > [<ffffffff81097cd0>] ? try_to_wake_up+0x390/0x390 > >> > [<ffffffff81086335>] flush_work+0x165/0x250 > >> > >> I suspect this is xlog_cil_push_now -> flush_work(&cil->xc_push_work) > >> right? I kind of got lost where this waits on an IO. > >> > > > > Yep. That means a CIL push is already in progress. We wait on that to > > complete here. After that, the resulting task queues execution of > > xlog_cil_push_work()->xlog_cil_push() on m_cil_workqueue. That task may > > submit I/O to the log. > > > > I don't see any reference to xlog_cil_push() anywhere in the traces here > > or in the bug referenced above, however..? > > Well, it's prefaced with "Interesting is:"... Sergey (the original > reporter, CCed here) might still have the rest of them. JFTR http://tracker.ceph.com/attachments/download/2769/full_kern_trace.txt [288420.754637] Workqueue: xfs-cil/rbd1 xlog_cil_push_work [xfs] [288420.754638] ffff880130c1fb38 0000000000000046 ffff880130c1fac8 ffff880130d72180 [288420.754640] 0000000000012b00 ffff880130c1fad8 ffff880130c1ffd8 0000000000012b00 [288420.754641] ffff8810297b6480 ffff880130d72180 ffffffffa03b1264 ffff8820263d6800 [288420.754643] Call Trace: [288420.754652] [<ffffffffa03b1264>] ? xlog_bdstrat+0x34/0x70 [xfs] [288420.754653] [<ffffffff816dd629>] schedule+0x29/0x70 [288420.754661] [<ffffffffa03b3b9c>] xlog_state_get_iclog_space+0xdc/0x2e0 [xfs] [288420.754669] [<ffffffffa03b1264>] ? xlog_bdstrat+0x34/0x70 [xfs] [288420.754670] [<ffffffff81097cd0>] ? try_to_wake_up+0x390/0x390 [288420.754678] [<ffffffffa03b4090>] xlog_write+0x190/0x730 [xfs] [288420.754686] [<ffffffffa03b5d9e>] xlog_cil_push+0x24e/0x3e0 [xfs] [288420.754693] [<ffffffffa03b5f45>] xlog_cil_push_work+0x15/0x20 [xfs] [288420.754695] [<ffffffff81084c19>] process_one_work+0x159/0x4f0 [288420.754697] [<ffffffff81084fdc>] process_scheduled_works+0x2c/0x40 [288420.754698] [<ffffffff8108579b>] worker_thread+0x29b/0x530 [288420.754699] [<ffffffff81085500>] ? create_worker+0x1d0/0x1d0 [288420.754701] [<ffffffff8108b6f9>] kthread+0xc9/0xe0 [288420.754703] [<ffffffff8108b630>] ? flush_kthread_worker+0x90/0x90 [288420.754705] [<ffffffff816e1b98>] ret_from_fork+0x58/0x90 [288420.754707] [<ffffffff8108b630>] ? flush_kthread_worker+0x90/0x90 -- Michal Hocko SUSE Labs