Re: [Xen-devel] Re: mem-event interface

To:	Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Subject:	Re: [Xen-devel] Re: mem-event interface
From:	Grzegorz Milos <grzegorz.milos@xxxxxxxxx>
Date:	Sun, 27 Jun 2010 16:45:52 +0100
Cc:	"Xen-Devel \(E-mail\)" <xen-devel@xxxxxxxxxxxxxxxxxxx>, George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "Bryan D. Payne" <bryan@xxxxxxxxxxxx>, Patrick Colp <pjcolp@xxxxxxxxx>, Andrew Peace <Andrew.Peace@xxxxxxxxxxxxx>, Steven Hand <Steven.Hand@xxxxxxxxxxxxx>
Delivery-date:	Sun, 27 Jun 2010 08:46:47 -0700
Dkim-signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type; bh=z8pM2dEJ5DwssKl2NdOYCw916KupvJrvqWYFDSnV8dk=; b=x7ZmxSxP3pnLu/+ysRRBVECm9vuE+uss4kr9ovGdOZ+W1EE3P+I2AX/nrlkMGdg+Oc EOc21W5I8KvngNePIYzLK+HYNFqTUjMDiTDZ4YY9pftchaa7kD8W9fOw8MLSY+mvsR7J oDbTpsmv5e4ltD2M7BtumkoOE9PCOMtj2Pox4=
Domainkey-signature:	a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=qzFc4wMkqQ/EOkJ5gkcv9GD1KVQ0MXWIaMbNCWAxf1A3Ip1T6/0npNc5sDcDehHMB2 VdZgTDZfnOlXGdv9fBxvyoS17aaV0evMa1qXSojBf8jmmxchQ5HdkfXF3iH0GW5cf/DC Hn/uXsqShEQWOJfEjE6KsYQ+oXUXswGldBjUo=
Envelope-to:	www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to:	<20100624091811.GC31695@xxxxxxxxxxxxxxxxxxxxxxx>
List-help:	<mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id:	Xen developer discussion <xen-devel.lists.xensource.com>
List-post:	<mailto:xen-devel@lists.xensource.com>
List-subscribe:	<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe:	<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References:	<AANLkTikydcTHLFmPNx_5kTsSYq7BM_u_l54tB3f3H_iT@xxxxxxxxxxxxxx> <AANLkTilKT2LoowaY_7RB-hKTTUMkhC_lLTohmohozKeH@xxxxxxxxxxxxxx> <AANLkTikTBCAj9gCM-Ksk2f85tGfySKfqcdI7Ojy9LU30@xxxxxxxxxxxxxx> <AANLkTimNnlittGra6kk3VWvDcWIRdw2HRBWnb3b2l3R-@xxxxxxxxxxxxxx> <AANLkTinwajCCxk8LtzfR6CwBqk-FZP4HvmsxMEHWthdn@xxxxxxxxxxxxxx> <AANLkTilJp4OPyG07RFpqYjIVclkaqXIWEG-ZUU_CNJTU@xxxxxxxxxxxxxx> <AANLkTinJ736hCNDhYDeZBZTTuMwKH8x265NoWVPYoco9@xxxxxxxxxxxxxx> <AANLkTim5L3NleKd71V_rihMXwYQnTIDdgBSpCIuJRXnW@xxxxxxxxxxxxxx> <AANLkTik0dlCjyh4nk7goM4V7uTv6j5yLwzF6OdhVI4-h@xxxxxxxxxxxxxx> <AANLkTikgLaQA95ocrMcSOCBWQbPfrRLPua0sS6F9mL44@xxxxxxxxxxxxxx> <20100624091811.GC31695@xxxxxxxxxxxxxxxxxxxxxxx>
Sender:	xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

> I agree that multiple rings are a good idea here - especially if we want
> to disaggregate and have event handlers in multiple domains.
>
> Maybe the ring-registering interface could take a type and a rangeset -
> that would reduce the amount of extra chatter at the cost of some more
> overhead in Xen.
>

Well, the trouble is what do units you express the ranges in. In pfns
belonging to a given guest, or in mfns? Either way memory sharing
would use <0 - max_{p,m}fn> rangeset most of the time. Similarly for
teh pager (I believe). Bryan, could you comment on XenAccess? I guess
rangesets would be useful there the most.

I certainly agree that we will have to swallow some complexity in Xen,
to make the interface efficient. Some filters will have to live in
Xen, in order not to generate unnecessarily large rate of no-op
events.

Thanks
Gregor

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

WARNING - OLD ARCHIVES

xen-devel

Re: [Xen-devel] Re: mem-event interface