Re: [Qemu-devel] [PATCH v4 0/5] blockjob: AioContext change support for mirror and backup

["Jason J. Herne" <jjherne@linux.vnet.ibm.com>]

On 06/14/2016 02:17 PM, Stefan Hajnoczi wrote:
> v4:
>   * Add .pause()/.resume() callbacks to really quiesce during
>     block_job_pause_point() [Paolo]
>   * Add AioContext change support for backup block job
>   * Tested drive_mirror + migration and drive_backup + reboot
>
> v3:
>   * Push infrastructure down into blockjob.c so other jobs can reuse it [Stefan]
>   * Tested with drive_mirror + migration [Stefan]
>
> v2:
>   * Fam introduced the concept of a synchronous aio_poll() loop to quiesce the
>     block job during detach
>
> When dataplane is enabled or disabled the drive switches to a new AioContext.
> The mirror and backup block jobs must also move to the new AioContext so that
> drive accesses are always made within its AioContext.
>
> This series extends the block job pause functionality so that detaching from an
> AioContext pauses the job and attaching to the new AioContext resumes the job.
>
> Pause points are added to the mirror job so that long I/O loops can yield for
> an AioContext switch.  Other block jobs need pause points too but this can be
> done as a follow-up series.

I just tested v4 on s390. It appears to fix our original problem without 
any hiccups.
Thank you Stefan! :) Let me know if you need any more testing.

-- 
-- Jason J. Herne (jjherne@linux.vnet.ibm.com)