From mboxrd@z Thu Jan 1 00:00:00 1970 From: Francois Romieu Subject: Re: [openib-general] Re: LLTX and netif_stop_queue Date: Thu, 20 Jan 2005 01:47:53 +0100 Message-ID: <20050120004753.GB2330@electric-eye.fr.zoreil.com> References: <1104764660.1048.578.camel@jzny.localdomain> <52brc68q05.fsf@topspin.com> <5cac192f05010308414a25b548@mail.gmail.com> <527jmu8nbw.fsf@topspin.com> <5cac192f0501030907c755135@mail.gmail.com> <20050103171227.GD7370@esmail.cup.hp.com> <1104812294.1085.53.camel@jzny.localdomain> <20050119144711.3fdd3d93.davem@davemloft.net> <20050119151853.259de49a@dxpl.pdx.osdl.net> <20050119154132.68f0bb4f.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stephen Hemminger , hadi@cyberus.ca, iod00d@hp.com, eric.lemoine@gmail.com, roland@topspin.com, netdev@oss.sgi.com, ak@suse.de, openib-general@openib.org, kaber@trash.net Return-path: To: "David S. Miller" Content-Disposition: inline In-Reply-To: <20050119154132.68f0bb4f.davem@davemloft.net> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org David S. Miller : [...] > Originally, dev->xmit_lock was added so that drivers that were SMP dumb > could stay that way. Thus preserving the guarentee that there would be > only one active call into the dev->hard_start_xmit method across the > entire system. I don't think any of that is relevant any longer. All > of our network drivers are pretty clean in this regard. (nit) Almost all. I used the fact that dev->hard_start_xmit was issued in a bh disabled context to exchange spinlock_irqsave for ordered ops on ring indexes so as to sync hard_start_xmit and the irq handler in the r8169 driver. It is a bit sick but Jon Mason reported it made a noticeable difference to avoid the irqsave on its 4 way ppc64 and nobody complained about it. -- Ueimor