From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: TUN problems (regression?) Date: Fri, 21 Dec 2012 11:32:43 +0800 Message-ID: <50D3D85B.1070605@redhat.com> References: <4151394.nMo40zlg68@sifl> <1356046697.21834.3606.camel@edumazet-glaptop> <20121220155001.538bbdb0@nehalam.linuxnetplumber.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , Paul Moore , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63591 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750875Ab2LUDcs (ORCPT ); Thu, 20 Dec 2012 22:32:48 -0500 In-Reply-To: <20121220155001.538bbdb0@nehalam.linuxnetplumber.net> Sender: netdev-owner@vger.kernel.org List-ID: On 12/21/2012 07:50 AM, Stephen Hemminger wrote: > On Thu, 20 Dec 2012 15:38:17 -0800 > Eric Dumazet wrote: > >> On Thu, 2012-12-20 at 18:16 -0500, Paul Moore wrote: >>> [CC'ing netdev in case this is a known problem I just missed ...] >>> >>> Hi Jason, >>> >>> I started doing some more testing with the multiqueue TUN changes and I ran >>> into a problem when running tunctl: running it once w/o arguments works as >>> expected, but running it a second time results in failure and a >>> kmem_cache_sanity_check() failure. The problem appears to be very repeatable >>> on my test VM and happens independent of the LSM/SELinux fixup patches. >>> >>> Have you seen this before? >>> >> Obviously code in tun_flow_init() is wrong... >> >> static int tun_flow_init(struct tun_struct *tun) >> { >> int i; >> >> tun->flow_cache = kmem_cache_create("tun_flow_cache", >> sizeof(struct tun_flow_entry), 0, 0, >> NULL); >> if (!tun->flow_cache) >> return -ENOMEM; >> ... >> } >> >> >> I have no idea why we would need a kmem_cache per tun_struct, >> and why we even need a kmem_cache. > Normally flow malloc/free should be good enough. > It might make sense to use private kmem_cache if doing hlist_nulls. > > > Acked-by: Stephen Hemminger Should be at least a global cache, I thought I can get some speed-up by using kmem_cache. Acked-by: Jason Wang > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html