mbox series

[0/3] iolatency bug fix

Message ID 20190124001655.92508-1-bo.liu@linux.alibaba.com (mailing list archive)
Headers show
Series iolatency bug fix | expand

Message

Liu Bo Jan. 24, 2019, 12:16 a.m. UTC 
This set is to fix a hang case if blk-iolatency is in use.

The 1st patch adds a warning for unexpected inflight counter.
The 2nd patch explains the hang problem with more details.
The 3nd patch is a cleanup of blk_mq_freeze_queue.

Liu Bo (3):
  Blk-iolatency: warn on negative inflight IO counter
  blk-iolatency: fix IO hang due to negative inflight counter
  blk-mq: remove duplicated definition of blk_mq_freeze_queue

 block/blk-iolatency.c | 56 ++++++++++++++++++++++++++++++++++++-------
 block/blk-mq.h        |  1 -
 2 files changed, 48 insertions(+), 9 deletions(-)

Comments

Jens Axboe Jan. 24, 2019, 6:11 p.m. UTC | #1 
On 1/23/19 5:16 PM, Liu Bo wrote:
> This set is to fix a hang case if blk-iolatency is in use.
> 
> The 1st patch adds a warning for unexpected inflight counter.
> The 2nd patch explains the hang problem with more details.
> The 3nd patch is a cleanup of blk_mq_freeze_queue.

This is much better. You'll want to reorder 1 and 2 though, it's a known
issue that we can hit the underflow condition before you fix the issue.
Liu Bo Jan. 24, 2019, 6:24 p.m. UTC | #2 
On Thu, Jan 24, 2019 at 10:11 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> On 1/23/19 5:16 PM, Liu Bo wrote:
> > This set is to fix a hang case if blk-iolatency is in use.
> >
> > The 1st patch adds a warning for unexpected inflight counter.
> > The 2nd patch explains the hang problem with more details.
> > The 3nd patch is a cleanup of blk_mq_freeze_queue.
>
> This is much better. You'll want to reorder 1 and 2 though, it's a known
> issue that we can hit the underflow condition before you fix the issue.
>

Oh sure, I'll send a v2.

thanks,
liubo