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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: "Fernando Luis Vázquez Cao" <fernando@oss.ntt.co.jp>,
	rusty@rustcorp.com.au, linux-kernel@vger.kernel.org,
	jeremy@xensource.com
Subject: Re: [PATCH 1/3] block: add queue flag for paravirt frontend drivers
Date: Tue, 04 Nov 2008 15:23:42 -0800	[thread overview]
Message-ID: <4910D97E.2030203@goop.org> (raw)
In-Reply-To: <20081027125624.GA22217@kernel.dk>

Jens Axboe wrote:
> On Mon, Oct 27 2008, Fernando Luis Vázquez Cao wrote:
>   
>> As is the case with SSD devices, we do not want to idle in AS/CFQ when
>> the block device is a paravirt front-end driver. This patch adds a flag
>> (QUEUE_FLAG_VIRT) which should be used by front-end drivers such as
>> virtio_blk and xen-blkfront to indicate a paravirtualized device.
>>     
>
> All three patches look fine, although we could just reuse
> QUEUE_FLAG_NONROT directly. But I agree it makes sense to make the
> distinction, so I've just applied 1-3.
>   

I guess in theory you could imagine that the virtual device is mapped 
directly onto a physical device, and the host OS does no scheduling, in 
which case it would be appropriate for the guest do the work.  But I 
think otherwise this makes sense.

    J

  reply	other threads:[~2008-11-04 23:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-26 12:48 [PATCH] virtio_blk: use noop elevator by default Fernando Luis Vázquez Cao
2008-08-26 14:39 ` Jens Axboe
2008-08-27  5:14   ` Fernando Luis Vázquez Cao
2008-10-27  9:44     ` [PATCH 1/3] block: add queue flag for paravirt frontend drivers Fernando Luis Vázquez Cao
2008-10-27 12:56       ` Jens Axboe
2008-11-04 23:23         ` Jeremy Fitzhardinge [this message]
2008-11-05  9:20           ` Jens Axboe
2008-11-05 10:49             ` Fernando Luis Vázquez Cao
2008-10-27  9:45     ` [PATCH 2/3] virtio_blk: set queue paravirt flag Fernando Luis Vázquez Cao
2008-10-27  9:45     ` [PATCH 3/3] xen-blkfront: " Fernando Luis Vázquez Cao
2008-10-27  9:43   ` [PATCH] virtio_blk: use noop elevator by default Fernando Luis Vázquez Cao

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