[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block la
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll |
Date: |
Wed, 29 Jul 2015 13:02:27 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 |
On 29/07/2015 12:57, Fam Zheng wrote:
> 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?
Yes, though I think you'd end up reverting patches 10 and 11 in the end.
All 11 patches are okay, though it would be great if you could post the
full series before this is applied.
Paolo
- [Qemu-block] [PATCH v2 05/11] aio: Mark ctx->notifier's client type as "context", (continued)
- [Qemu-block] [PATCH v2 05/11] aio: Mark ctx->notifier's client type as "context", Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 06/11] dataplane: Mark host notifiers' client type as "dataplane", Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 07/11] aio-posix: introduce aio_{disable, enable}_clients, Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 08/11] aio-win32: Implement aio_{disable, enable}_clients, Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 09/11] block: Introduce bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 10/11] block: Replace nested aio_poll with bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll,
Paolo Bonzini <=
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-block] [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/30
Re: [Qemu-block] [PATCH v2 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane, Paolo Bonzini, 2015/07/29