Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932763AbaBDTzq (ORCPT ); Tue, 4 Feb 2014 14:55:46 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:9538 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755039AbaBDTzo (ORCPT ); Tue, 4 Feb 2014 14:55:44 -0500 X-IronPort-AV: E=Sophos;i="4.95,781,1384300800"; d="scan'208";a="97927001" Message-ID: <52F145BE.3090606@citrix.com> Date: Tue, 4 Feb 2014 19:55:42 +0000 From: Zoltan Kiss User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Wei Liu CC: , , , , , David Miller Subject: Re: [PATCH net-next v2] xen-netback: Rework rx_work_todo References: <1389805867-22409-1-git-send-email-zoltan.kiss@citrix.com> <20140120163814.GE11681@zion.uk.xensource.com> <52F13D24.5090405@citrix.com> In-Reply-To: <52F13D24.5090405@citrix.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.133] X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/14 19:19, Zoltan Kiss wrote: > On 20/01/14 16:38, Wei Liu wrote: >> On Wed, Jan 15, 2014 at 05:11:07PM +0000, Zoltan Kiss wrote: >>> The recent patch to fix receive side flow control (11b57f) solved the >>> spinning >>> thread problem, however caused an another one. The receive side can >>> stall, if: >>> - [THREAD] xenvif_rx_action sets rx_queue_stopped to true >>> - [INTERRUPT] interrupt happens, and sets rx_event to true >>> - [THREAD] then xenvif_kthread sets rx_event to false >>> - [THREAD] rx_work_todo doesn't return true anymore >>> >>> Also, if interrupt sent but there is still no room in the ring, it >>> take quite a >>> long time until xenvif_rx_action realize it. This patch ditch that >>> two variable, >>> and rework rx_work_todo. If the thread finds it can't fit more skb's >>> into the >>> ring, it saves the last slot estimation into rx_last_skb_slots, >>> otherwise it's >>> kept as 0. Then rx_work_todo will check if: >>> - there is something to send to the ring (like before) >>> - there is space for the topmost packet in the queue >>> >>> I think that's more natural and optimal thing to test than two bool >>> which are >>> set somewhere else. >>> >>> Signed-off-by: Zoltan Kiss >> >> Sorry for the delay. >> >> Paul, thanks for reviewing. >> >> Acked-by: Wei Liu > > Hi, > > This patch haven't made it to net-next yet, maybe because the subject > doesn't suggest that this is a bugfix. I suggest to apply it as soon as > possible, otherwise netback will be quite broken. I've reposted it with clearer subject, sorry for being too vague Zoli -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/