Date: Thu, 2 Feb 2006 13:29:01 -0600
From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>, serue@us.ibm.com, arjan@infradead.org,
       frankeh@watson.ibm.com, clg@fr.ibm.com, mrmacman_g4@mac.com,
       alan@lxorguk.ukuu.org.uk,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>, devel@openvz.org
Subject: Re: [RFC][PATCH 5/7] VPIDs: vpid/pid conversion in VPID enabled case
Message-ID: <20060202192901.GC10920@sergelap.austin.ibm.com>
References: <43E22B2D.1040607@openvz.org> <43E23398.7090608@openvz.org> <1138899951.29030.30.camel@localhost.localdomain>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1138899951.29030.30.camel@localhost.localdomain>
User-Agent: Mutt/1.5.11
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1510
Lines: 33

Quoting Dave Hansen (haveblue@us.ibm.com):
> On Thu, 2006-02-02 at 19:30 +0300, Kirill Korotaev wrote:
> > This is the main patch which contains all vpid-to-pid conversions
> > and auxilliary stuff. Virtual pids are distinguished from real ones
> > by the VPID_BIT bit set. Conversion from vpid to pid and vice versa
> > is performed in two ways: fast way, when vpid and it's according pid
> > differ only in VPID_BIT bit set ("linear" case), and more complex way,
> > when pid may correspond to any vpid ("sparse" case) - in this case we
> > use a hash-table based mapping. 
> 
> This is an interesting approach.  Could you elaborate a bit on on why
> you need the two different approaches?  What conditions cause the switch
> to the sparse approach?
> 
> Also, if you could separate those two approaches out into two different
> patches, it would be much easier to get a grasp about what's going on.
> One of them is just an optimization, right?
> 
> Did you happen to catch Linus's mail about his preferred approach?  
> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=113874154731279&w=2

And in particular, is there any functionality which you could not
implement by using this approach, which you can implement with the
pid_to_vpid approach?

thanks,
-serge
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/