From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net-next V4 0/6] switch to use tx skb array in tun Date: Fri, 8 Jul 2016 17:14:19 +0800 Message-ID: <577F6EEB.9080908@redhat.com> References: <20160708091855-mutt-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20160708091855-mutt-send-email-mst@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" , Craig Gallek Cc: kvm@vger.kernel.org, Eric Dumazet , netdev , LKML , virtualization@lists.linux-foundation.org, brouer@redhat.com, David Miller List-Id: virtualization@lists.linuxfoundation.org CgpPbiAyMDE25bm0MDfmnIgwOOaXpSAxNDoxOSwgTWljaGFlbCBTLiBUc2lya2luIHdyb3RlOgo+ IE9uIFdlZCwgSnVsIDA2LCAyMDE2IGF0IDAxOjQ1OjU4UE0gLTA0MDAsIENyYWlnIEdhbGxlayB3 cm90ZToKPj4gPk9uIFRodSwgSnVuIDMwLCAyMDE2IGF0IDI6NDUgQU0sIEphc29uIFdhbmc8amFz b3dhbmdAcmVkaGF0LmNvbT4gIHdyb3RlOgo+Pj4gPiA+SGkgYWxsOgo+Pj4gPiA+Cj4+PiA+ID5U aGlzIHNlcmllcyB0cmllcyB0byBzd2l0Y2ggdG8gdXNlIHNrYiBhcnJheSBpbiB0dW4uIFRoaXMg aXMgdXNlZCB0bwo+Pj4gPiA+ZWxpbWluYXRlIHRoZSBzcGlubG9jayBjb250ZW50aW9uIGJldHdl ZW4gcHJvZHVjZXIgYW5kIGNvbnN1bWVyLiBUaGUKPj4+ID4gPmNvbnZlcnNpb24gd2FzIHN0cmFp Z2h0Zm9yd2FyZDoganVzdCBpbnRyb2RjZSBhIHR4IHNrYiBhcnJheSBhbmQgdXNlCj4+PiA+ID5p dCBpbnN0ZWFkIG9mIHNrX3JlY2VpdmVfcXVldWUuCj4+ID4KPj4gPkknbSBzZWVpbmcgdGhlIHNw bGF0IGJlbG93IGFmdGVyIHRoaXMgc2VyaWVzLiAgSSdtIHN0aWxsIHdyYXBwaW5nIG15Cj4+ID5o ZWFkIGFyb3VuZCB0aGlzIGNvZGUsIGJ1dCBpdCBhcHBlYXJzIHRvIGJlIGhhcHBlbmluZyBiZWNh dXNlIHRoZQo+PiA+dHVuX3N0cnVjdCBwYXNzZWQgaW50byB0dW5fcXVldWVfcmVzaXplIGlzIHVu aW5pdGlhbGl6ZWQuCj4+ID5TcGVjaWZpY2FsbHksIGl0ZXJhdGlvbiBvdmVyIHRoZSBkaXNhYmxl ZCBsaXN0X2hlYWQgZmFpbHMgYmVjYXVzZSBwcmV2Cj4+ID49IG5leHQgPSBOVUxMLiAgVGhpcyBz ZWVtcyB0byBoYXBwZW4gd2hlbiBhIHN0YXJ0dXAgc2NyaXB0IG9uIG15IHRlc3QKPj4gPm1hY2hp bmUgY2hhbmdlcyB0aGUgcXVldWUgbGVuZ3RoLiAgSSdsbCB0cnkgdG8gZmlndXJlIG91dCB3aGF0 J3MKPj4gPmhhcHBlbmluZywgYnV0IGlmIGl0J3Mgb2J2aW91cyB0byBzb21lb25lIGVsc2UgZnJv bSB0aGUgc3RhY2ssIHBsZWFzZQo+PiA+bGV0IG1lIGtub3cuCj4gRG9uJ3Qgc2VlIGFueXRoaW5n IG9idmlvdXMuIEknbSB0cmF2ZWxpbmcsIHdpbGwgbG9vayBhdCBpdCB3aGVuIEknbSBiYWNrCj4g dW5sZXNzIGl0J3MgZml4ZWQgYnkgdGhlbi4gSmFzb24sIGFueSBpZGVhPwo+CgpMb29rcyBsaWtl IENyYWlnIGhhcyBwb3N0ZWQgYSBmaXggdG8gdGhpczoKCmh0dHA6Ly9wYXRjaHdvcmsub3psYWJz Lm9yZy9wYXRjaC82NDU2NDUvCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fClZpcnR1YWxpemF0aW9uIG1haWxpbmcgbGlzdApWaXJ0dWFsaXphdGlvbkBsaXN0 cy5saW51eC1mb3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91bmRhdGlvbi5vcmcv bWFpbG1hbi9saXN0aW5mby92aXJ0dWFsaXphdGlvbg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754499AbcGHJOf (ORCPT ); Fri, 8 Jul 2016 05:14:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41847 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754069AbcGHJO1 (ORCPT ); Fri, 8 Jul 2016 05:14:27 -0400 Subject: Re: [PATCH net-next V4 0/6] switch to use tx skb array in tun To: "Michael S. Tsirkin" , Craig Gallek References: <20160708091855-mutt-send-email-mst@redhat.com> Cc: netdev , LKML , David Miller , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Eric Dumazet , brouer@redhat.com From: Jason Wang Message-ID: <577F6EEB.9080908@redhat.com> Date: Fri, 8 Jul 2016 17:14:19 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160708091855-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 08 Jul 2016 09:14:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016年07月08日 14:19, Michael S. Tsirkin wrote: > On Wed, Jul 06, 2016 at 01:45:58PM -0400, Craig Gallek wrote: >> >On Thu, Jun 30, 2016 at 2:45 AM, Jason Wang wrote: >>> > >Hi all: >>> > > >>> > >This series tries to switch to use skb array in tun. This is used to >>> > >eliminate the spinlock contention between producer and consumer. The >>> > >conversion was straightforward: just introdce a tx skb array and use >>> > >it instead of sk_receive_queue. >> > >> >I'm seeing the splat below after this series. I'm still wrapping my >> >head around this code, but it appears to be happening because the >> >tun_struct passed into tun_queue_resize is uninitialized. >> >Specifically, iteration over the disabled list_head fails because prev >> >= next = NULL. This seems to happen when a startup script on my test >> >machine changes the queue length. I'll try to figure out what's >> >happening, but if it's obvious to someone else from the stack, please >> >let me know. > Don't see anything obvious. I'm traveling, will look at it when I'm back > unless it's fixed by then. Jason, any idea? > Looks like Craig has posted a fix to this: http://patchwork.ozlabs.org/patch/645645/