WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] [PATCH] Reduce overhead in find_domain_by_id() [0/2]

To: "Keir Fraser" <keir@xxxxxxxxxxxxx>, "Apparao, Padmashree K" <padmashree.k.apparao@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] Reduce overhead in find_domain_by_id() [0/2]
From: "Santos, Jose Renato G" <joserenato.santos@xxxxxx>
Date: Thu, 7 Dec 2006 22:17:54 -0600
Cc: "Turner, Yoshio" <yoshio_turner@xxxxxx>, Jose Renato Santos <jsantos@xxxxxxxxxx>, G John Janakiraman <john@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 07 Dec 2006 20:18:27 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C19DB32A.5AAE%keir@xxxxxxxxxxxxx>
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AccY1tScspQxhfmoTr62Wf8QIRwz8wAO8dbrAAZN7LAAAQAGywAfw6ewABIlWWoAIgAvcA==
Thread-topic: [Xen-devel] [PATCH] Reduce overhead in find_domain_by_id() [0/2]
 

> -----Original Message-----
> From: Keir Fraser [mailto:keir@xxxxxxxxxxxxx] 
> Sent: Thursday, December 07, 2006 4:02 AM
> To: Santos, Jose Renato G; Keir Fraser; Apparao, Padmashree 
> K; xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Turner, Yoshio; Jose Renato Santos; G John Janakiraman
> Subject: Re: [Xen-devel] [PATCH] Reduce overhead in 
> find_domain_by_id() [0/2]
> 
> On 7/12/06 03:49, "Santos, Jose Renato G" 
> <joserenato.santos@xxxxxx> wrote:
> 
> > Can't think of anything else. If you want I can remove these and 
> > submit a revised patch.
> > It seems that there is not much more we could remove. Not 
> sure if you 
> > have something else in mind...
> 
> I suppose the patch isn't actually as big as I first 
> imagined. I'll review it and probably apply it pretty much as 
> is. It's just that RCU has always seemed rather over 
> complicated to me (lots of different queues, for example) for 
> what should be a rather simple concept to implement. This is 
> possibly just ignorance on my part. :-)
> 
>

Yes, the multiple queues seems somewhat complicated, but
I think we need them to be able to handle multiple callbacks.
Maybe we can get rid of of of them ("done")...

> As for per-cpu refcounts, I suspect a better scheme would be 
> find_domain_by_id_noref(). Idea being that often we take a 
> reference for a short period of time (in particular, scope of 
> one function) and with delayed destruction we can now safely 
> use a found domain pointer with no refcnt increment.
> 

Good point. This is indeed a much better scheme. I will 
work out a patch for find_domain_by_id_noref().

Thanks

Renato

>  -- Keir
> 
> 

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