From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755704AbbHYQcj (ORCPT ); Tue, 25 Aug 2015 12:32:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59886 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751400AbbHYQch (ORCPT ); Tue, 25 Aug 2015 12:32:37 -0400 Message-ID: <55DC98A3.7010601@redhat.com> Date: Tue, 25 Aug 2015 12:32:35 -0400 From: Vlad Yasevich Reply-To: vyasevic@redhat.com Organization: Red Hat User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Jason Wang , "Michael S. Tsirkin" CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Patrick McHardy Subject: Re: [PATCH net-next] macvtap/macvlan: use IFF_NO_QUEUE References: <1440405192-25926-1-git-send-email-jasowang@redhat.com> <20150825131608-mutt-send-email-mst@redhat.com> <55DC51C1.5090201@redhat.com> In-Reply-To: <55DC51C1.5090201@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/25/2015 07:30 AM, Jason Wang wrote: > > > On 08/25/2015 06:17 PM, Michael S. Tsirkin wrote: >> On Mon, Aug 24, 2015 at 04:33:12PM +0800, Jason Wang wrote: >>>> For macvlan, switch to use IFF_NO_QUEUE instead of tx_queue_len = 0. >>>> >>>> For macvtap, after commit 6acf54f1cf0a6747bac9fea26f34cfc5a9029523 >>>> ("macvtap: Add support of packet capture on macvtap >>>> device."). Multiqueue macvtap suffers from single qdisc lock >>>> contention. This is because macvtap claims a non zero tx_queue_len and >>>> it reuses this value as it socket receive queue size.Thanks to >>>> IFF_NO_QUEUE, we can remove the lock contention without breaking >>>> existing socket receive queue length logic. >>>> >>>> Cc: Patrick McHardy >>>> Cc: Vladislav Yasevich >>>> Cc: Michael S. Tsirkin >>>> Signed-off-by: Jason Wang >> Seems to make sense. Give me a day or two to get over the jet lag >> (and get out from under the pile of mail accumulated while I was traveling), >> I'll review properly and ack. >> > > A note on this patch: only default qdisc were removed but we don't lose > the ability to attach a qdisc to macvtap (though it may cause lock > contention on multiqueue case). > Wouldn't that lock contention be solved if we really had multiple queues for multi-queue macvtaps? -vlad