netdev - Re: [PATCH 09/18] virtio: use avail

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110519072734.GB31253@redhat.com>
Date:	Thu, 19 May 2011 10:27:34 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	linux-kernel@...r.kernel.org, Carsten Otte <cotte@...ibm.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	linux390@...ibm.com, Martin Schwidefsky <schwidefsky@...ibm.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Shirley Ma <xma@...ibm.com>, lguest@...ts.ozlabs.org,
	virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
	linux-s390@...r.kernel.org, kvm@...r.kernel.org,
	Krishna Kumar <krkumar2@...ibm.com>,
	Tom Lendacky <tahm@...ux.vnet.ibm.com>, steved@...ibm.com,
	habanero@...ux.vnet.ibm.com
Subject: Re: [PATCH 09/18] virtio: use avail_event index

On Wed, May 18, 2011 at 09:49:42AM +0930, Rusty Russell wrote:
> On Tue, 17 May 2011 09:10:31 +0300, "Michael S. Tsirkin" <mst@...hat.com> wrote:
> > Well one can imagine a driver doing:
> > 
> > 	while (virtqueue_get_buf()) {
> > 		virtqueue_add_buf()
> > 	}
> > 	virtqueue_kick()
> > 
> > which looks sensible (batch kicks) but might
> > process any number of bufs between kicks.
> 
> No, we currently only expose the buffers in the kick, so it can only
> fill the ring doing that.
> 
> We could change that (and maybe that's worth looking at)...

That's actually what one of the early patches in the series did.
I guess I can try and reorder the patches, I do believe
it makes sense to publish immediately as this way
host can work in parallel with the guest.

> > If we look at drivers closely enough, I think none
> > of them do the equivalent of the above, but not 100% sure.
> 
> I'm pretty sure we don't have this kind of 'echo' driver yet.  Drivers
> tend to take OS requests and queue them.  The only one which does
> anything even partially sophisticated is the net driver...
> 
> Thanks,
> Rusty.

I guess I'll just need to do the legwork and check then.

-- 
MST
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html