From: Andi Kleen <andi@firstfloor.org>
To: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: Satoshi Uchida <s-uchida@ap.jp.nec.com>,
Andi Kleen <andi@firstfloor.org>,
xen-devel@lists.xensource.com
Subject: Re: Is QoS of virtual disk not necessary?
Date: Fri, 24 Aug 2007 22:53:50 +0200 [thread overview]
Message-ID: <20070824205350.GA23558@one.firstfloor.org> (raw)
In-Reply-To: <C2F4D6B6.148D3%Keir.Fraser@cl.cam.ac.uk>
On Fri, Aug 24, 2007 at 06:40:54PM +0100, Keir Fraser wrote:
> On 24/8/07 18:26, "Andi Kleen" <andi@firstfloor.org> wrote:
>
> >> Another nice thing would be that if we do not use CFQ then we do not need a
> >> kernel thread per VBD.
> >
> > It would be probably easy to extend CFQ2 to use an user passed identifier
> > instead of per task for sharing if that's your goal. For a kernel driver
> > like blkback you could just switch around multiple current->io_contexts.
>
> Does current->io_context get latched before submit_bh() (or whatever similar
> function it is we use) returns? Is this true even in older 2.6 kernels with
> old CFQ?
It obviously has to because you could exit in the next call.
The context is reference counted and lazily freed.
-Andi
next prev parent reply other threads:[~2007-08-24 20:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-22 9:32 Is QoS of virtual disk not necessary? Satoshi Uchida
2007-08-22 12:39 ` Keir Fraser
2007-08-24 8:27 ` Satoshi Uchida
2007-08-24 15:36 ` Keir Fraser
2007-08-24 17:26 ` Andi Kleen
2007-08-24 17:40 ` Keir Fraser
2007-08-24 20:53 ` Andi Kleen [this message]
[not found] ` <006101c7e953$15afd230$4c87380a@ad.spf.cl.nec.co.jp>
2007-08-28 11:24 ` Andi Kleen
2007-08-24 9:48 ` how many processors does xen support in hardware ? tgh
2007-08-24 10:06 ` pradeep singh rautela
2007-08-24 11:31 ` tgh
2007-08-24 13:34 ` how many processors does xen support in hardware? Puthiyaparambil, Aravindh
2007-08-24 14:32 ` pradeep singh rautela
2007-08-24 14:49 ` Keir Fraser
2007-08-24 18:00 ` pradeep singh
2007-08-24 18:04 ` Keir Fraser
2007-08-24 18:15 ` pradeep singh
2007-08-25 7:29 ` tgh
[not found] ` <46d0121a.0589300a.5f14.061c@mx.google.com>
2007-08-26 13:26 ` tgh
2007-08-24 15:02 ` Puthiyaparambil, Aravindh
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