Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424234AbWKIXCK (ORCPT ); Thu, 9 Nov 2006 18:02:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1424233AbWKIXCJ (ORCPT ); Thu, 9 Nov 2006 18:02:09 -0500 Received: from rwcrmhc15.comcast.net ([216.148.227.155]:47814 "EHLO rwcrmhc15.comcast.net") by vger.kernel.org with ESMTP id S1424229AbWKIXCG (ORCPT ); Thu, 9 Nov 2006 18:02:06 -0500 Message-ID: <4553B07A.6050002@soleranetworks.com> Date: Thu, 09 Nov 2006 15:49:30 -0700 From: "Jeff V. Merkey" User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050921 Red Hat/1.7.12-1.4.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jesse Brandeburg CC: Linux kernel , NetDEV list Subject: Re: e1000 driver 2.6.18 - how to waste processor cycles References: <45524E3A.7080301@soleranetworks.com> <4807377b0611081701i26ee7ce0k1f822dbbe52c2c8@mail.gmail.com> <4552EAFC.5060400@soleranetworks.com> <4807377b0611091445s11575f5ej15c7bf7126bb5658@mail.gmail.com> In-Reply-To: <4807377b0611091445s11575f5ej15c7bf7126bb5658@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1172 Lines: 49 Jesse Brandeburg wrote: > On 11/9/06, Jeffrey V. Merkey wrote: > >> In the case I am referring to, the memory is already mapped with a >> previous call, which means it may be getting >> mapped twice. > > > I guess maybe I'm not keeping up with you. This is what I see looking > in 2.6.18, i see e1000_clean_rx_irq: Check e1000_alloc_rx_buffers: if (skb already exists in ring buffer) goto map_skb: else dev_alloc_skb ( drop through to map_skb) map_skb: pci_map_single Jeff > > check done bit > pci_unmap_single > copybreak and recycle > OR > hand buffer up stack > > the only branch before the unmap is the napi break out, and in that > case we don't change any memory state, so alloc will not do anything. > > As for alloc rx, we always map, because we always unmapped. > > Did I miss something? I would appreciate a more detailed explanation > of what you see going wrong. > > - 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/