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/
Home Products Support Community News


Re: [Xen-ia64-devel] flush_tlb_mask and grant_table on ia64

To: "Xu, Anthony" <anthony.xu@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>, <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-ia64-devel] flush_tlb_mask and grant_table on ia64
From: Tristan Gingold <Tristan.Gingold@xxxxxxxx>
Date: Fri, 21 Apr 2006 09:42:34 +0200
Delivery-date: Fri, 21 Apr 2006 00:39:17 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <2BF508F394C196468CCBEC031320DCDF3809F4@pdsmsx405>
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
References: <2BF508F394C196468CCBEC031320DCDF3809F4@pdsmsx405>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.5
Le Vendredi 21 Avril 2006 09:27, Xu, Anthony a écrit :
> From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
> >[mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Tristan
> >Gingold
> >Sent: 2006?4?21? 15:24
> >To: xen-devel@xxxxxxxxxxxxxxxxxxx; xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> >Subject: [Xen-ia64-devel] flush_tlb_mask and grant_table on ia64
> >
> >Hi,
> >
> >on IA64 flushing the whole TLB is very expensive: this is a cpu tlb flush
> > and clearing 16MB of memory (virtual tlb).
> >However, flushing an address range is rather cheap.  Flushing an address
> > range on every processors is also cheap (no IPI).
> >
> >Unfortunatly Xen common code flushes the whole TLB after unmapping grant
> >reference.
> Agreed
> >Currently, this is not done on IA64 because domain_dirty_cpumask is never
> > set (bug!).
> >
> >We can flush TLB by range within destroy_grant_host_mapping.  But then we
> > need to disable the flush_tlb_mask call.
> >
> >What is the best solution?
> It depends on the coverage of VHPT and coverage of purged page.
From my point of view, the problem is not the number of frames to be purge.  I 
suppose only a few pages are unmapped per unmap_grant_ref call (although I 
may be wrong here).

From my point of view the problem is how to make Xen common code more arch 


Xen-ia64-devel mailing list