From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754145AbdA3TGx (ORCPT ); Mon, 30 Jan 2017 14:06:53 -0500 Received: from mail-pf0-f194.google.com ([209.85.192.194]:35613 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047AbdA3TGv (ORCPT ); Mon, 30 Jan 2017 14:06:51 -0500 Message-ID: <1485803209.6360.111.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [PATCH] xen-netfront: Delete rx_refill_timer in xennet_disconnect_backend() From: Eric Dumazet To: Boris Ostrovsky Cc: jgross@suse.com, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, vineethp@amazon.com, wei.liu2@citrix.com, paul.durrant@citrix.com, stable@vger.kernel.org Date: Mon, 30 Jan 2017 11:06:49 -0800 In-Reply-To: <40057d9d-c615-1a2b-63a2-ab717c29d659@oracle.com> References: <1485798346-4425-1-git-send-email-boris.ostrovsky@oracle.com> <1485799651.6360.101.camel@edumazet-glaptop3.roam.corp.google.com> <40057d9d-c615-1a2b-63a2-ab717c29d659@oracle.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2017-01-30 at 13:23 -0500, Boris Ostrovsky wrote: > We do netif_carrier_off() first thing in xennet_disconnect_backend() and > the only place where the timer is rearmed is xennet_alloc_rx_buffers(), > which is guarded by netif_carrier_ok() check. Oh well, testing netif_carrier_ok() in packet processing fast path looks unusual and a waste of cpu cycles. I've never seen that pattern before. If one day, we remove this netif_carrier_ok() test during a cleanup, then the race window will open again.