From: Paolo Bonzini <pbonzini@redhat.com>
To: Ming Lei <ming.lei@canonical.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>,
Fam Zheng <famz@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v1 2/3] linux-aio: implement io plug and unplug
Date: Tue, 01 Jul 2014 08:16:09 +0200 [thread overview]
Message-ID: <53B25229.6050105@redhat.com> (raw)
In-Reply-To: <CACVXFVNE1qH30FM63OFU1taVx6Z4T_Ki5_Rr1Wa527bVhQoCaA@mail.gmail.com>
Il 01/07/2014 03:05, Ming Lei ha scritto:
>> > Busy waiting is not acceptable here (it can be unbounded if, for example, an
>> > NFS server is on the other side of a network partition). You have to add a
>> > bottom half to qemu_laio_state that calls ioq_submit, and schedule it after
>> > calling io_getevents.
>> >
>> > If the bottom half is already scheduled and the queue is full, I guess
>> > there's no other choice than returning -EAGAIN from ioq_enqueue and
>> > ultimately to the guest.
> That is a bit complicated, as you mentioned it is close to
> 2.1 release, could we just keep it simple to return failure to guest
> after retrying several times? Actually, previous dataplane handles
> it by exit(-1), which is unfriendly absolutely.
Indeed, I'd say do not even bother retrying several times. :)
Paolo
next prev parent reply other threads:[~2014-07-01 6:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-30 15:47 [Qemu-devel] [PATCH v1 0/3] linux-aio: introduce submit I/O at batch Ming Lei
2014-06-30 15:47 ` [Qemu-devel] [PATCH v1 1/3] block: block: introduce bdrv_io_plug() and bdrv_io_unplug() Ming Lei
2014-06-30 16:10 ` Paolo Bonzini
2014-06-30 16:15 ` Ming Lei
2014-06-30 16:18 ` Paolo Bonzini
2014-06-30 16:29 ` Ming Lei
2014-06-30 15:47 ` [Qemu-devel] [PATCH v1 2/3] linux-aio: implement io plug and unplug Ming Lei
2014-06-30 17:31 ` Paolo Bonzini
2014-07-01 1:05 ` Ming Lei
2014-07-01 6:16 ` Paolo Bonzini [this message]
2014-06-30 15:47 ` [Qemu-devel] [PATCH v1 3/3] dataplane: submit I/O at batch Ming Lei
2014-06-30 16:11 ` Paolo Bonzini
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