[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context |
Date: |
Wed, 16 Mar 2016 18:51:17 +0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, 03/16 11:27, Paolo Bonzini wrote:
>
>
> On 16/03/2016 11:10, Fam Zheng wrote:
> > An empty begin/end pair is almost the same as a bare bdrv_drain except
> > the aio_poll inside is wrapped by
> > aio_disable_external/aio_enable_external.
> >
> > This is safer, and is the only way to achieve quiescence in this
> > aio_poll(), because bdrv_drained_begin/end pair cannot span across
> > context detach/attach options, so it's not possible to do by the caller.
>
> I'm still not sure about this patch.
>
> When starting dataplane, the ioeventfd is registered with iohandler.c so
> bdrv_drained_begin/end is not necessary.
You are right, and looks like the k->set_host_notifier() above
blk_set_aio_context would disable the fd anyway.
>
> Likewise when stopping dataplane bdrv_set_aio_context is called after
> the thread has been stopped and thus the ioeventfd is not registered
> anymore as an external client.
Right.
Fam
- [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Fam Zheng, 2016/03/16
- [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context, Fam Zheng, 2016/03/16
- [Qemu-devel] [PATCH 2/4] block-backend: Introduce blk_drained_begin/end, Fam Zheng, 2016/03/16
- [Qemu-devel] [PATCH 3/4] virtio-blk: Use blk_drained_begin/end around dataplane stop, Fam Zheng, 2016/03/16
- [Qemu-devel] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Fam Zheng, 2016/03/16
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Stefan Hajnoczi, 2016/03/17
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Paolo Bonzini, 2016/03/17
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Fam Zheng, 2016/03/22
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Paolo Bonzini, 2016/03/22
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Cornelia Huck, 2016/03/23
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Paolo Bonzini, 2016/03/23
- Re: [Qemu-devel] [Qemu-block] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Christian Borntraeger, 2016/03/23