From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754234AbaCMKnL (ORCPT ); Thu, 13 Mar 2014 06:43:11 -0400 Received: from smtp.citrix.com ([66.165.176.89]:9010 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754186AbaCMKnG (ORCPT ); Thu, 13 Mar 2014 06:43:06 -0400 X-IronPort-AV: E=Sophos;i="4.97,646,1389744000"; d="scan'208";a="110955921" Message-ID: <1394707350.25873.34.camel@kazak.uk.xensource.com> Subject: Re: [PATCH net-next] xen-netback: Schedule NAPI from dealloc thread instead of callback From: Ian Campbell To: Wei Liu CC: Zoltan Kiss , , , , Date: Thu, 13 Mar 2014 10:42:30 +0000 In-Reply-To: <20140313101720.GA16807@zion.uk.xensource.com> References: <1394658281-2488-1-git-send-email-zoltan.kiss@citrix.com> <20140313101720.GA16807@zion.uk.xensource.com> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.80] X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-03-13 at 10:17 +0000, Wei Liu wrote: > On Wed, Mar 12, 2014 at 09:04:41PM +0000, Zoltan Kiss wrote: > > If there are unconsumed requests in the ring, but there isn't enough free > > pending slots, the NAPI instance deschedule itself. As the frontend won't send > > any more interrupts in this case, it is the task of whoever release the pending > > slots to schedule the NAPI instance in this case. Originally it was done in the > > callback, but it's better at the end of the dealloc thread, otherwise there is > > a risk that the NAPI instance just deschedule itself as the dealloc thread > > couldn't release any used slot yet. However, as there are a lot of pending > > packets, NAPI will be scheduled again, and it is very unlikely that the dealloc > > thread can't release enough slots in the meantime. > > > > So this patch restores the property that "only two parties access the > ring", right? I think so, and therefore: Acked-by: Ian Campbell Ian.