From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: ronniesahlberg@gmail.com, Peter Lieven <pl@kamp.de>,
qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}
Date: Tue, 08 Oct 2013 14:35:29 +0200 [thread overview]
Message-ID: <5253FC11.3010309@redhat.com> (raw)
In-Reply-To: <20131008123315.GE25109@dhcp-200-207.str.redhat.com>
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.
Paolo
next prev parent reply other threads:[~2013-10-08 12:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-02 15:41 [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk} Peter Lieven
2013-10-02 15:46 ` Paolo Bonzini
2013-10-02 15:54 ` Peter Lieven
2013-10-02 15:55 ` Paolo Bonzini
2013-10-02 15:57 ` Peter Lieven
2013-10-08 12:33 ` Kevin Wolf
2013-10-08 12:35 ` Paolo Bonzini [this message]
2013-10-08 12:39 ` Kevin Wolf
2013-10-11 7:35 ` Peter Lieven
2013-11-25 10:47 ` Peter Lieven
2013-11-25 10:54 ` Paolo Bonzini
2013-11-25 10:56 ` Peter Lieven
2013-11-25 10:57 ` Paolo Bonzini
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