Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932363Ab2EWNTY (ORCPT ); Wed, 23 May 2012 09:19:24 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:43240 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747Ab2EWNTX (ORCPT ); Wed, 23 May 2012 09:19:23 -0400 Date: Wed, 23 May 2012 09:12:42 -0400 From: Konrad Rzeszutek Wilk To: Simon Graham Cc: Ian Campbell , Ben Hutchings , "xen-devel@lists.xensource.com" , "netdev@vger.kernel.org" , "davem@davemloft.net" , "linux-kernel@vger.kernel.org" , Adnan Misherfi Subject: Re: [PATCH] xen/netback: calculate correctly the SKB slots. Message-ID: <20120523131242.GA15406@phenom.dumpdata.com> References: <1337621793-12486-1-git-send-email-konrad.wilk@oracle.com> <1337627640.2979.33.camel@bwh-desktop.uk.solarflarecom.com> <1337678512.10118.40.camel@zakaz.uk.xensource.com> <20120522180901.GC22488@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1539 Lines: 37 On Tue, May 22, 2012 at 03:01:55PM -0400, Simon Graham wrote: > > > > > > > > int i, copy_off; > > > > > > > > > > count = DIV_ROUND_UP( > > > > > - offset_in_page(skb->data)+skb_headlen(skb), > > PAGE_SIZE); > > > > > + offset_in_page(skb->data + skb_headlen(skb)), > > PAGE_SIZE); > > > > > > > > The new version would be equivalent to: > > > > count = offset_in_page(skb->data + skb_headlen(skb)) != 0; > > > > which is not right, as netbk_gop_skb() will use one slot per page. > > > > > > Just outside the context of this patch we separately count the frag > > > pages. > > > > > > However I think you are right if skb->data covers > 1 page, since the > > > new version can only ever return 0 or 1. I expect this patch papers > > over > > > the underlying issue by not stopping often enough, rather than > > actually > > > fixing the underlying issue. > > > > Ah, any thoughts? Have you guys seen this behavior as well? > > We ran into this same problem and the fix we've been running with for a while now (been meaning to submit it!) is: Where is the patchqueue of the patches? Is it only on the src.rpm or is it in some nice mercurial tree? Asking b/c if we run into other trouble it would be also time-saving for us (and I presume other companies too) to check that. Thanks! -- 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/