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Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode
From: |
Christian Borntraeger |
Subject: |
Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode |
Date: |
Thu, 10 Mar 2016 10:03:05 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 03/10/2016 02:51 AM, Fam Zheng wrote:
[...]
> The aio_poll() inside "blk_set_aio_context(s->conf->conf.blk, s->ctx)" looks
> suspicious:
>
> main thread iothread
> ----------------------------------------------------------------------------
> virtio_blk_handle_output()
> virtio_blk_data_plane_start()
> vblk->dataplane_started = true;
> blk_set_aio_context()
> bdrv_set_aio_context()
> bdrv_drain()
> aio_poll()
> <snip...>
> virtio_blk_handle_output()
> /* s->dataplane_started is true */
> !!! -> virtio_blk_handle_request()
> event_notifier_set(ioeventfd)
> aio_poll()
>
> virtio_blk_handle_request()
>
> Christian, could you try the followed patch? The aio_poll above is replaced
> with a "limited aio_poll" that doesn't disptach ioeventfd.
>
> (Note: perhaps moving "vblk->dataplane_started = true;" after
> blk_set_aio_context() also *works around* this.)
>
> ---
>
> diff --git a/block.c b/block.c
> index ba24b8e..e37e8f7 100644
> --- a/block.c
> +++ b/block.c
> @@ -4093,7 +4093,9 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
>
> void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
> {
> - bdrv_drain(bs); /* ensure there are no in-flight requests */
> + /* ensure there are no in-flight requests */
> + bdrv_drained_begin(bs);
> + bdrv_drained_end(bs);
>
> bdrv_detach_aio_context(bs);
>
That seems to do the trick.
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Christian Borntraeger, 2016/03/09
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Paolo Bonzini, 2016/03/09
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Christian Borntraeger, 2016/03/09
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Paolo Bonzini, 2016/03/09
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Fam Zheng, 2016/03/09
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode,
Christian Borntraeger <=
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Christian Borntraeger, 2016/03/10
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Paolo Bonzini, 2016/03/11
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, tu bo, 2016/03/14
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Fam Zheng, 2016/03/15
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Cornelia Huck, 2016/03/15
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Paolo Bonzini, 2016/03/15
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, Fam Zheng, 2016/03/15
- Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode, tu bo, 2016/03/16