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Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bd
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll |
Date: |
Wed, 29 Jul 2015 18:57:25 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, 07/29 09:37, Paolo Bonzini wrote:
>
>
> On 29/07/2015 06:42, Fam Zheng wrote:
> > @@ -2613,6 +2613,8 @@ bool bdrv_aio_poll(AioContext *ctx, bool blocking)
> > {
> > bool ret;
> >
> > + aio_disable_clients(ctx, AIO_CLIENT_DATAPLANE | AIO_CLIENT_NBD_SERVER);
> > ret = aio_poll(ctx, blocking);
> > + aio_enable_clients(ctx, AIO_CLIENT_DATAPLANE | AIO_CLIENT_NBD_SERVER);
> > return ret;
>
> This is not enough, because another thread's aio_poll can sneak in
> between calls to bdrv_aio_poll if the AioContext lock is released, and
> they will use the full set of clients.
>
> Similar to your v1, it works with the large critical sections we
> currently have, but it has the same problem in the longer term.
Can we add more disable/enable pairs around bdrv_drain on top?
Fam
>
> The clients have to be disabled around calls to bdrv_drain, as you were
> doing when you had pause/resume notifiers. Patches 1-8 however are ok.
>
> Paolo
>
- [Qemu-devel] [PATCH v2 03/11] block: Mark fd handlers as "protocol", (continued)
- [Qemu-devel] [PATCH v2 03/11] block: Mark fd handlers as "protocol", Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 05/11] aio: Mark ctx->notifier's client type as "context", Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 06/11] dataplane: Mark host notifiers' client type as "dataplane", Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 07/11] aio-posix: introduce aio_{disable, enable}_clients, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 08/11] aio-win32: Implement aio_{disable, enable}_clients, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 09/11] block: Introduce bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 10/11] block: Replace nested aio_poll with bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll,
Fam Zheng <=
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/30
Re: [Qemu-devel] [PATCH v2 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane, Paolo Bonzini, 2015/07/29