On Thu, Jun 27, 2013 at 11:21:51AM -0400, Dave Jones wrote:
> On Thu, Jun 27, 2013 at 10:52:18PM +1000, Dave Chinner wrote:
>
>
> > > Yup, that's about three of orders of magnitude faster on this
> > > workload....
> > >
> > > Lightly smoke tested patch below - it passed the first round of
> > > XFS data integrity tests in xfstests, so it's not completely
> > > busted...
> >
> > And now with even less smoke out that the first version. This one
> > gets though a full xfstests run...
>
> :sadface:
>
> [ 567.680836] ======================================================
> [ 567.681582] [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
> [ 567.682389] 3.10.0-rc7+ #9 Not tainted
> [ 567.682862] ------------------------------------------------------
> [ 567.683607] trinity-child2/8665 [HC0[0]:SC0[0]:HE0:SE1] is trying to
> acquire:
> [ 567.684464] (&sb->s_type->i_lock_key#3){+.+...}, at: [<ffffffff811d74e5>]
> sync_inodes_sb+0x225/0x3b0
> [ 567.685632]
> and this task is already holding:
> [ 567.686334] (&(&wb->wb_list_lock)->rlock){..-...}, at:
> [<ffffffff811d7451>] sync_inodes_sb+0x191/0x3b0
> [ 567.687506] which would create a new lock dependency:
> [ 567.688115] (&(&wb->wb_list_lock)->rlock){..-...} ->
> (&sb->s_type->i_lock_key#3){+.+...}
.....
> other info that might help us debug this:
>
> [ 567.750396] Possible interrupt unsafe locking scenario:
>
> [ 567.752062] CPU0 CPU1
> [ 567.753025] ---- ----
> [ 567.753981] lock(&sb->s_type->i_lock_key#3);
> [ 567.754969] local_irq_disable();
> [ 567.756085]
> lock(&(&wb->wb_list_lock)->rlock);
> [ 567.757368] lock(&sb->s_type->i_lock_key#3);
> [ 567.758642] <Interrupt>
> [ 567.759370] lock(&(&wb->wb_list_lock)->rlock);
Oh, that's easy enough to fix. It's just changing the wait_sb_inodes
loop to use a spin_trylock(&inode->i_lock), moving the inode to
the end of the sync list, dropping all locks and starting again...
Cheers,
Dave.
--
Dave Chinner
da...@fromorbit.com
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