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Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue |
Date: |
Thu, 3 Jul 2014 12:22:04 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 03.07.2014 um 11:51 hat Ming Lei geschrieben:
> Hi Kevin,
>
> On Thu, Jul 3, 2014 at 5:40 PM, Kevin Wolf <address@hidden> wrote:
> > Am 02.07.2014 um 14:18 hat Ming Lei geschrieben:
> >> This patch implements .bdrv_io_plug, .bdrv_io_unplug and
> >> .bdrv_flush_io_queue callbacks for linux-aio Block Drivers,
> >> so that submitting I/O as a batch can be supported on linux-aio.
> >>
> >> Signed-off-by: Ming Lei <address@hidden>
> >
> > Just a couple of minor comments, see inline.
>
> Thanks for your review.
>
> >> +void laio_io_plug(BlockDriverState *bs, void *aio_ctx)
> >> +{
> >> + struct qemu_laio_state *s = aio_ctx;
> >> +
> >> + s->io_q.plugged++;
> >> +}
> >> +
> >> +int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug)
> >> +{
> >> + struct qemu_laio_state *s = aio_ctx;
> >> + int ret = 0;
> >> +
> >
> > How about an assert(s->io_q.plugged > 0); here?
>
> how about just adding a warning because flush io queue uses
> the function too?
Good point, this is what the assertion should look like then:
assert(s->io_q.plugged > 0 || !unplug);
> Also that is why 'plugged' is defined as signed.
I don't understand. The flush function leaves s->io_q.plugged alone
(otherwise it would be buggy), so how can it ever become negative? And
if you say that a negative value is valid, what would it even mean?
> >
> >> + if (unplug && --s->io_q.plugged > 0)
> >> + return 0;
> >
> > Missing braces.
> >
> >> +
> >> + if (s->io_q.idx > 0) {
> >> + ret = ioq_submit(s);
> >> + }
> >> +
> >> + return ret;
> >> +}
Kevin
- [Qemu-devel] [PATCH v4 1/3] block: block: introduce APIs for submitting IO as, (continued)
- [Qemu-devel] [PATCH v4 1/3] block: block: introduce APIs for submitting IO as, Ming Lei, 2014/07/02
- [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Ming Lei, 2014/07/02
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Kevin Wolf, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Ming Lei, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Paolo Bonzini, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Ming Lei, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Paolo Bonzini, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Ming Lei, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue,
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Ming Lei, 2014/07/03
- Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Kevin Wolf, 2014/07/03
Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue, Stefan Hajnoczi, 2014/07/03
[Qemu-devel] [PATCH v4 3/3] dataplane: submit I/O as a batch, Ming Lei, 2014/07/02
Re: [Qemu-devel] [PATCH v4 3/3] dataplane: submit I/O as a batch, Stefan Hajnoczi, 2014/07/03