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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 12:30:12 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 03.07.2014 um 12:24 hat Ming Lei geschrieben:
> On Thu, Jul 3, 2014 at 6:22 PM, Kevin Wolf <address@hidden> wrote:
> > 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);
>
> OK, will do it.
>
> >> 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?
>
> I mean it is easy to detect bug with negative value, :-)
Ah, I see. That makes some sense then. :-)
Kevin
- Re: [Qemu-devel] [PATCH v4 1/3] block: block: introduce APIs for submitting IO as, (continued)
- [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, 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, 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
Re: [Qemu-devel] [PATCH v4 3/3] dataplane: submit I/O as a batch, Stefan Hajnoczi, 2014/07/03