From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] net: bcmgenet: rewrite bcmgenet_rx_refill() Date: Fri, 13 Mar 2015 15:48:44 -0400 (EDT) Message-ID: <20150313.154844.1460460664757494447.davem@davemloft.net> References: <20150312224800.AE7A7220365@puck.mtv.corp.google.com> <55032C64.3010706@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: pgynther@google.com, netdev@vger.kernel.org, jaedon.shin@gmail.com To: f.fainelli@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:53369 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752043AbbCMTsq (ORCPT ); Fri, 13 Mar 2015 15:48:46 -0400 In-Reply-To: <55032C64.3010706@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Florian Fainelli Date: Fri, 13 Mar 2015 11:28:52 -0700 > On 12/03/15 15:48, Petri Gynther wrote: >> Currently, bcmgenet_desc_rx() calls bcmgenet_rx_refill() at the end of >> Rx packet processing loop, after the current Rx packet has already been >> passed to napi_gro_receive(). However, bcmgenet_rx_refill() might fail >> to allocate a new Rx skb, thus leaving a hole on the Rx queue where no >> valid Rx buffer exists. >> >> To eliminate this situation: >> 1. Rewrite bcmgenet_rx_refill() to retain the current Rx skb on the Rx >> queue if a new replacement Rx skb can't be allocated and DMA-mapped. >> In this case, the data on the current Rx skb is effectively dropped. >> 2. Modify bcmgenet_desc_rx() to call bcmgenet_rx_refill() at the top of >> Rx packet processing loop, so that the new replacement Rx skb is >> already in place before the current Rx skb is processed. > > Reviewed-by: Florian Fainelli > Tested-by: Florian Fainelli > > Thanks! Have not noticed any performance impact doing 64B/1500B testing. Applied, thanks everyone.