From: Fam Zheng <famz@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, tubo@linux.vnet.ibm.com,
Stefan Hajnoczi <stefanha@redhat.com>,
cornelia.huck@de.ibm.com, borntraeger@de.ibm.com
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 [thread overview]
Message-ID: <20160316105117.GA8038@ad.usersys.redhat.com> (raw)
In-Reply-To: <56E93528.6020002@redhat.com>
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.
Right.
Fam
next prev parent reply other threads:[~2016-03-16 10:51 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 10:10 [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context Fam Zheng
2016-03-16 10:27 ` Paolo Bonzini
2016-03-16 10:51 ` Fam Zheng [this message]
2016-03-16 10:10 ` [Qemu-devel] [PATCH 2/4] block-backend: Introduce blk_drained_begin/end Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 3/4] virtio-blk: Use blk_drained_begin/end around dataplane stop Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH Fam Zheng
2016-03-17 15:00 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2016-03-17 15:07 ` Paolo Bonzini
2016-03-22 12:52 ` Fam Zheng
2016-03-22 18:05 ` Paolo Bonzini
2016-03-23 8:10 ` Cornelia Huck
2016-03-23 9:08 ` Paolo Bonzini
2016-03-23 9:12 ` Christian Borntraeger
2016-03-24 8:19 ` tu bo
2016-03-24 8:32 ` Cornelia Huck
2016-03-24 8:47 ` Cornelia Huck
2016-03-24 9:31 ` Cornelia Huck
2016-03-16 10:28 ` [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop Paolo Bonzini
2016-03-16 10:49 ` Christian Borntraeger
2016-03-16 11:09 ` Paolo Bonzini
2016-03-16 11:24 ` Christian Borntraeger
2016-03-16 12:55 ` Paolo Bonzini
2016-03-16 13:38 ` Christian Borntraeger
2016-03-16 13:45 ` Paolo Bonzini
2016-03-17 0:39 ` Fam Zheng
2016-03-17 11:03 ` tu bo
2016-03-21 10:57 ` Fam Zheng
2016-03-21 11:15 ` Cornelia Huck
2016-03-21 12:45 ` Fam Zheng
2016-03-21 13:02 ` Cornelia Huck
2016-03-21 23:45 ` Fam Zheng
2016-03-22 8:06 ` Cornelia Huck
2016-03-22 7:10 ` tu bo
2016-03-22 7:18 ` Fam Zheng
2016-03-22 9:07 ` Cornelia Huck
2016-03-22 9:46 ` Paolo Bonzini
2016-03-22 11:59 ` Cornelia Huck
2016-03-22 12:11 ` Paolo Bonzini
2016-03-22 12:54 ` Cornelia Huck
2016-03-17 12:22 ` tu bo
2016-03-17 12:39 ` Christian Borntraeger
2016-03-17 13:02 ` Cornelia Huck
2016-03-17 15:02 ` Paolo Bonzini
2016-03-17 15:07 ` Christian Borntraeger
2016-03-17 15:15 ` Christian Borntraeger
2016-03-17 15:16 ` Christian Borntraeger
2016-03-17 16:08 ` Christian Borntraeger
2016-03-18 15:03 ` Paolo Bonzini
2016-03-21 9:42 ` Fam Zheng
2016-03-21 11:10 ` Christian Borntraeger
2016-03-21 12:17 ` Cornelia Huck
2016-03-21 13:47 ` TU BO
2016-03-21 13:54 ` Paolo Bonzini
2016-03-21 14:19 ` Cornelia Huck
2016-03-22 0:31 ` Fam Zheng
2016-03-16 11:32 ` Cornelia Huck
2016-03-16 11:48 ` Paolo Bonzini
2016-03-16 11:56 ` Cornelia Huck
2016-03-16 11:59 ` Paolo Bonzini
2016-03-16 12:22 ` Cornelia Huck
2016-03-16 12:32 ` Paolo Bonzini
2016-03-16 12:42 ` Cornelia Huck
2016-03-16 12:49 ` Paolo Bonzini
2016-03-16 13:04 ` Cornelia Huck
2016-03-16 13:10 ` Paolo Bonzini
2016-03-16 13:14 ` Cornelia Huck
2016-03-16 13:15 ` Paolo Bonzini
2016-03-16 11:52 ` Cornelia Huck
2016-03-16 11:54 ` Paolo Bonzini
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