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Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context |
Date: |
Wed, 16 Mar 2016 11:27:52 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
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.
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.
Paolo
- [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
- Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context,
Paolo Bonzini <=
- [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