On Thu, Sep 01 2016 at 1:59pm -0400, Bart Van Assche <bart.vanassche@xxxxxxxxxxx> wrote: > On 09/01/2016 09:12 AM, Mike Snitzer wrote: > >On Thu, Sep 01 2016 at 11:50am -0400, > >Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > >>On Thu, Sep 01 2016 at 11:31am -0400, > >>Bart Van Assche <bart.vanassche@xxxxxxxxxxx> wrote: > >> > >>>On 09/01/2016 08:05 AM, Mike Snitzer wrote: > >>>>I've staged most of your changes (with slight tweaks), see: > >>>>https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-4.9 > >>>> > >>>>Only remaining issue is the queue dying race(s) in dm-multipath. > >>> > >>>Thanks Mike! Two minor comments though: > >>>* In dm_start_queue(), I think that the queue_flag_clear_unlocked() > >>> call should be converted into queue_flag_clear() and that it should > >>> be protected by the block layer queue lock. Every call of > >>> queue_flag_clear_unlocked() after block device initialization has > >>> finished is wrong if blk_cleanup_queue() can be called concurrently. > >> > >>OK, I'll have a look. > > > >Please see/test the dm-4.8 and dm-4.9 branches (dm-4.9 being rebased > >ontop of dm-4.8): > >https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-4.8 > >https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-4.9 > > Hello Mike, > > The result of my tests of the dm-4.9 branch is as follows: > * With patch "dm mpath: check if path's request_queue is dying in > activate_path()" I still see every now and then that CPU usage of > one of the kworker threads jumps to 100%. So you're saying that the dying queue check is still needed in the path selector? Would be useful to know why the 100% is occuring. Can you get a stack trace during this time? > * A "if (!blk_queue_stopped(q))" test needs to be added in > dm_stop_queue() to avoid the following hang (that test was present > in my version of the patch that adds the > blk_mq_{freeze,unfreeze}_queue() calls): > > sysrq: SysRq : Show Blocked State > task PC stack pid father > multipathd D ffff8803c8d37b80 0 3242 1 0x00000000 > Call Trace: > [<ffffffff81627087>] schedule+0x37/0x90 > [<ffffffff813097e1>] blk_mq_freeze_queue_wait+0x51/0xb0 > [<ffffffff8130be05>] blk_mq_freeze_queue+0x15/0x20 > [<ffffffffa034d882>] dm_stop_queue+0x62/0xc0 [dm_mod] > [<ffffffffa0342a1b>] dm_swap_table+0x2fb/0x370 [dm_mod] > [<ffffffffa0347875>] dev_suspend+0x95/0x220 [dm_mod] > [<ffffffffa03480fc>] ctl_ioctl+0x1fc/0x550 [dm_mod] > [<ffffffffa034845e>] dm_ctl_ioctl+0xe/0x20 [dm_mod] > [<ffffffff811ee27f>] do_vfs_ioctl+0x8f/0x690 > [<ffffffff811ee8bc>] SyS_ioctl+0x3c/0x70 > [<ffffffff8162d125>] entry_SYSCALL_64_fastpath+0x18/0xa8 OK, I've adjusted accordingly and pushed dm-4.8 and dm-4.9 again (with force, sorry about that). -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
