[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_

From: Fam Zheng
Subject: Re: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context
Date: Wed, 16 Mar 2016 18:51:17 +0800
User-agent: Mutt/1.5.21 (2010-09-15)

On Wed, 03/16 11:27, Paolo Bonzini wrote:
> 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.

You are right, and looks like the k->set_host_notifier() above
blk_set_aio_context would disable the fd anyway.

> 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.



reply via email to

[Prev in Thread] Current Thread [Next in Thread]