On Tue 31-01-12 11:14:15, Dave Chinner wrote:
> I also found this oddity on both XFS and ext4:
>
> flush-253:32-3400 [001] 1936151.384563: writeback_start: bdi 253:32: sb_dev 0:0 nr_pages=-898403 sync_mode=0 kupdate=0 range_cyclic=1 background=1 reason=background
> flush-253:32-3400 [005] 1936151.455845: writeback_start: bdi 253:32: sb_dev 0:0 nr_pages=-911663 sync_mode=0 kupdate=0 range_cyclic=1 background=1 reason=background
> flush-253:32-3400 [006] 1936151.596298: writeback_start: bdi 253:32: sb_dev 0:0 nr_pages=-931332 sync_mode=0 kupdate=0 range_cyclic=1 background=1 reason=background
> flush-253:32-3400 [006] 1936151.719074: writeback_start: bdi 253:32: sb_dev 0:0 nr_pages=-951001 sync_mode=0 kupdate=0 range_cyclic=1 background=1 reason=background
>
> That's indicating the work->nr_pages is starting extremely negative,
> which should not be the case. The highest I saw was around -2m.
> Something is not working right there, as writeback is supposed to
> terminate if work->nr_pages < 0....
Ugh, what kernel is this? The tracepoint is just a couple of lines after
if (work->nr_pages <= 0)
break;
so I really don't see how that could happen.
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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