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Re: [Qemu-devel] [RFC PATCH 00/11] aio: Introduce handler type to fix ne
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [RFC PATCH 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane |
Date: |
Thu, 23 Jul 2015 10:15:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 |
On 23/07/2015 08:32, Fam Zheng wrote:
>
> What is realized in this series is similar except the "disable, poll, enable"
> method, instead the bit mask of interesting client types is passed to
> aio_poll() (to be exact, passed to aio_poll_clients()). That is because,
> aio_poll may release the AioContext lock around ppoll, avoiding state will
> make
> the interface clearer.
However, this means that you must keep the AioContext lock during all
the long-running operations. Is this actually necessary? The original
purpose of keeping the lock (which didn't quite work) was to block out
dataplane operations.
Also, this requirements means you really need the AioContext lock to be
recursive. This is not a huge deal, but I'd prefer that requirement not
to be too ingrained.
Paolo
> After this series, block layer aio_poll() will only process those "protocol"
> fds that are used in block I/O, plus the ctx->notifier for aio_notify();
> other
> aio_poll()'s keep unchanged.
>
> The biggest advantage over approaches [1] and [2] is, no change is needed in
> virtio-{blk,scsi}-dataplane code, also this doesn't depend on converting QMP
> to
> coroutines.
- [Qemu-devel] [RFC PATCH 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane, Fam Zheng, 2015/07/23
- [Qemu-devel] [RFC PATCH 02/11] aio: Save type to AioHandler, Fam Zheng, 2015/07/23
- [Qemu-devel] [RFC PATCH 01/11] aio: Introduce "type" in aio_set_fd_handler and aio_set_event_notifier, Fam Zheng, 2015/07/23
- [Qemu-devel] [RFC PATCH 04/11] aio-win32: Implement aio_poll_clients, Fam Zheng, 2015/07/23
- [Qemu-devel] [RFC PATCH 08/11] dataplane: Mark host notifiers' client type as "dataplane", Fam Zheng, 2015/07/23
- [Qemu-devel] [RFC PATCH 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/23
- Re: [Qemu-devel] [RFC PATCH 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane,
Paolo Bonzini <=
[Qemu-devel] [RFC PATCH 06/11] nbd: Mark fd handlers client type as "nbd server", Fam Zheng, 2015/07/23
[Qemu-devel] [RFC PATCH 10/11] block: Replace nested aio_poll with bdrv_aio_poll, Fam Zheng, 2015/07/23
[Qemu-devel] [RFC PATCH 09/11] block: Introduce bdrv_aio_poll, Fam Zheng, 2015/07/23
[Qemu-devel] [RFC PATCH 05/11] block: Mark fd handlers as "protocol", Fam Zheng, 2015/07/23
[Qemu-devel] [RFC PATCH 07/11] aio: Mark ctx->notifier's client type as "context", Fam Zheng, 2015/07/23
[Qemu-devel] [RFC PATCH 03/11] aio-posix: Introduce aio_poll_clients, Fam Zheng, 2015/07/23