From mboxrd@z Thu Jan 1 00:00:00 1970 From: ANNIE LI Subject: Re: Is: SKB_MAX_LEN bites again. Was: Re: bug disabling guest interface Date: Sun, 10 Mar 2013 12:48:46 +0800 Message-ID: <513C10AE.9090105@oracle.com> References: <5139A56D.30107@crc.id.au> <00bf01ce1c34$395a4f20$ac0eed60$@jacekowski.org> <20130308203636.GA5422@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130308203636.GA5422@phenom.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: Ian Campbell , 'Steven Haigh' , xen-devel@lists.xen.org, Wei.Liu2@citrix.com, Jacek Milewicz List-Id: xen-devel@lists.xenproject.org On 2013-3-9 4:36, Konrad Rzeszutek Wilk wrote: > On Fri, Mar 08, 2013 at 08:36:37PM +0100, Jacek Milewicz wrote: >> Hi All >> >>> Is there any further information on a possible fix for this? Thoughts? >>> Ideas? As it seems to be hitting multiple sites, I'd like to get it >> fixed asap... >> >> There are 3 ways I can see this fixed: >> - update guests so all have same MAX_SKB_FRAGS (that includes windows >> drivers (windows drivers use 19 for MAX_SKB_FRAGS)) >> -add some sort of negotiation between host and guest >> - change MAX_SKB_FRAGS to 19 to accommodate all guests >> >> Unfortunately first one requires changes to the guest and most don't have >> that luxury. So the only way I see it could be fixed without breaking >> compatibility even more is > Ugh. The negotiations between host and guest is probably the best > choice. The issues you are going to hit are that you might need > to redo the skbs to match what the frontend's max is. > > Annie, Wei, Ian - were there some RFC patches floating around > for this? Actually I did plan to do it, but failed to start it because of windows WHQL things. Thanks Annie > >> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h >> index 821c7f4..82de0f5 100644 >> --- a/include/linux/skbuff.h >> +++ b/include/linux/skbuff.h >> @@ -143,8 +143,8 @@ struct sk_buff; >> * Since GRO uses frags we allocate at least 16 regardless of page >> * size. >> */ >> -#if (65536/PAGE_SIZE + 1)< 16 >> -#define MAX_SKB_FRAGS 16UL >> +#if (65536/PAGE_SIZE + 1)< 19 >> +#define MAX_SKB_FRAGS 19UL >> #else >> #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1) >> #endif >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xen.org >> http://lists.xen.org/xen-devel >>