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Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev,
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk} |
Date: |
Tue, 8 Oct 2013 14:39:08 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 08.10.2013 um 14:35 hat Paolo Bonzini geschrieben:
> Il 08/10/2013 14:33, Kevin Wolf ha scritto:
> >>> > > this converts read, write and flush functions from aio to coroutines.
> >> >
> >> > I'm not sure it's already the time for this... Cancellation sucks in
> >> > QEMU, and this is going to make things even worse.
> > Not sure what you're referring to. If you mean iscsi_aio_cancel(), isn't
> > it dead code anyway since we changed block.c to use coroutines for
> > everything? bdrv_co_io_em() even throws the acb away, so even if you
> > wanted, there's no way to cancel the request even today.
>
> SCSI tries to use cancellation, and this results in VCPU threads
> starving all other threads. So I would like to introduce cancellation
> points for coroutines.
Sounds like a nice thing to have, but it's unrelated to this patch.
Cancellation means waiting for request completion before and after the
patch.
Kevin
- [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}, Peter Lieven, 2013/10/02
- Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}, Paolo Bonzini, 2013/10/02
- Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}, Kevin Wolf, 2013/10/08
- Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}, Paolo Bonzini, 2013/10/08
- Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk},
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}, Peter Lieven, 2013/10/11