From: Paolo Bonzini <pbonzini@redhat.com>
To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org, armbru@redhat.com, jcody@redhat.com,
qemu-devel@nongnu.org, mreitz@redhat.com,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 11/11] block: Block "device IO" during bdrv_drain and bdrv_drain_all
Date: Wed, 13 May 2015 17:25:10 +0200 [thread overview]
Message-ID: <55536CD6.5040008@redhat.com> (raw)
In-Reply-To: <20150513151715.GH30644@ad.nay.redhat.com>
On 13/05/2015 17:17, Fam Zheng wrote:
>> >
>> > It can be the topic of a separate series. But this patch brings a
>> > false sense of security (either the blocker is unnecessary, or it
>> > needs to last after bdrv_drain returns), so I think it should be
>> > dropped.
> Doesn't this let bdrv_drain_all return when virtio-blk-dataplane is having high
> workload, in places where you say "the blocker is unnecessary"?
Yes, you're right. Please document it in the commit message and the
code, it's tricky.
Paolo
next prev parent reply other threads:[~2015-05-13 15:25 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 17:28 [Qemu-devel] [PATCH v2 00/11] Fix transactional snapshot with virtio-blk dataplane and NBD export Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 01/11] block: Add op blocker type "device IO" Fam Zheng
2015-05-13 11:32 ` Wen Congyang
2015-05-13 12:04 ` Paolo Bonzini
2015-05-13 15:02 ` Fam Zheng
2015-05-13 15:09 ` Paolo Bonzini
2015-05-14 2:40 ` Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 02/11] block: Add op blocker notifier list Fam Zheng
2015-05-14 5:32 ` Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 03/11] block-backend: Add blk_op_blocker_add_notifier Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 04/11] virtio-blk: Move complete_request to 'ops' structure Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 05/11] virtio-blk: Don't handle output when there is "device IO" op blocker Fam Zheng
2015-05-13 10:26 ` Paolo Bonzini
2015-05-13 11:09 ` Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 06/11] nbd-server: Clear "can_read" when "device io" blocker is set Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 07/11] blockdev: Block device IO during internal snapshot transaction Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 08/11] blockdev: Block device IO during external " Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 09/11] blockdev: Block device IO during drive-backup transaction Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 10/11] blockdev: Block device IO during blockdev-backup transaction Fam Zheng
2015-05-13 11:22 ` Wen Congyang
2015-05-13 12:55 ` Fam Zheng
2015-05-14 1:12 ` Wen Congyang
2015-05-14 1:53 ` Fam Zheng
2015-05-13 12:21 ` Paolo Bonzini
2015-05-13 15:08 ` Paolo Bonzini
2015-05-13 15:34 ` Fam Zheng
2015-05-13 17:28 ` [Qemu-devel] [PATCH v2 11/11] block: Block "device IO" during bdrv_drain and bdrv_drain_all Fam Zheng
2015-05-13 10:26 ` Paolo Bonzini
2015-05-13 11:08 ` Fam Zheng
2015-05-13 11:33 ` Paolo Bonzini
2015-05-13 15:17 ` Fam Zheng
2015-05-13 15:25 ` Paolo Bonzini [this message]
2015-05-14 3:02 ` Fam Zheng
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