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

[Xen-devel] Re: mthca use of dma_sync_single is bogus

To: Lukas Hejtmanek <xhejtman@xxxxxxxxxxx>
Subject: [Xen-devel] Re: mthca use of dma_sync_single is bogus
From: Roland Dreier <rdreier@xxxxxxxxx>
Date: Tue, 10 Jul 2007 12:08:43 -0700
Authentication-results: sj-dkim-1; header.From=rdreier@xxxxxxxxx; dkim=pass ( sig from cisco.com/sjdkim1004 verified; );
Cc: Keir Fraser <keir@xxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, "Michael S. Tsirkin" <mst@xxxxxxxxxxxxxxxxxx>, general@xxxxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 17 Jul 2007 05:02:30 -0700
Dkim-signature: v=0.5; a=rsa-sha256; q=dns/txt; l=677; t=1184094525; x=1184958525; c=relaxed/simple; s=sjdkim1004; h=Content-Type:From:Subject:Content-Transfer-Encoding:MIME-Version; d=cisco.com; i=rdreier@xxxxxxxxx; z=From:=20Roland=20Dreier=20<rdreier@xxxxxxxxx> |Subject:=20Re=3A=20mthca=20use=20of=20dma_sync_single=20is=20bogus |Sender:=20; bh=qwnYyVVuQPYv/jm7JK75winwrGqjBo/n33u/23KquA0=; b=nV6wrMehtSZXRVK6ybdB+DGZV1QjBlbFMy0r0Q6KU830G6gVnXN71dWuYyhs9hXk5YePBR4i sKwN1iGUWt3W02YVOVa3bxjjxvizGbAaeAzc1lyGWGXHU9FmbRWqggUqUv4bcdItlD3G1CGTDR iQV4TNA9iKXIlr8PM4QH04qRM=;
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20070710190018.GK3885@xxxxxxxxxxx> (Lukas Hejtmanek's message of "Tue, 10 Jul 2007 21:00:19 +0200")
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>
References: <adalkdpxopo.fsf@xxxxxxxxx> <20070709213913.GB20052@xxxxxxxxxxxxxx> <adamyy4vjo9.fsf@xxxxxxxxx> <20070710141409.GH3885@xxxxxxxxxxx> <ada7ip8b0be.fsf@xxxxxxxxx> <20070710190018.GK3885@xxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Gnus/5.1007 (Gnus v5.10.7) XEmacs/21.4.20 (linux)
 > I think he spoke about coherent, didn't he? On i386/x86_64, the consistent 
 > and
 > coherent are the same but on some architectures they are not and I think that
 > using consistent (in particular pci_alloc_consistent) is exactly what should
 > be used. Keir also recommended to use this one.

coherent and consistent are synonyms.  It's confusing because there is
pci_alloc_consistent(), which is in general just a wrapper for
dma_alloc_coherent().

 > And moreover, it avoids using swiotlb and bounce buffers, I think. Am I 
 > right,
 > Keir?

Yes, but I'm not really willing to make things worse for standard i386
just to make Xen work a little better.

 - R.

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

<Prev in Thread] Current Thread [Next in Thread>