Messages in this thread |  | | Date | Wed, 5 Nov 2008 10:20:17 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH 1/3] block: add queue flag for paravirt frontend drivers |
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On Tue, Nov 04 2008, Jeremy Fitzhardinge wrote: > 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.
For that specific case, it should just not set the flag.
-- Jens Axboe
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