Re: [Qemu-devel] [PATCH for-2.11] throttle-groups: forget timer and schedule next TGM on detach

[Alberto Garcia]

On Thu 16 Nov 2017 12:21:50 PM CET, Stefan Hajnoczi wrote:
> tg->any_timer_armed[] must be cleared when detaching pending timers from
> the AioContext.  Failure to do so leads to hung I/O because it looks
> like there are still timers pending when in fact they have been removed.
>
> Other ThrottleGroupMembers might have requests pending too so it's
> necessary to schedule the next TGM so it can set a timer.
>
> This patch fixes hung I/O when QEMU is launched with drives that are in
> the same throttling group:
>
>   (guest)$ dd if=/dev/zero of=/dev/vdb oflag=direct bs=512 &
>   (guest)$ dd if=/dev/zero of=/dev/vdc oflag=direct bs=512 &
>   (qemu) stop
>   (qemu) cont
>   ...I/O is stuck...
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>

Reviewed-by: Alberto Garcia <address@hidden>

Berto