From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [PATCH] Prevent netpoll hanging when link is down Date: Fri, 8 Oct 2004 17:00:01 -0500 Sender: netdev-bounce@oss.sgi.com Message-ID: <20041008220001.GE31237@waste.org> References: <20041006232544.53615761@jack.colino.net> <20041006214322.GG31237@waste.org> <20041007075319.6b31430d@jack.colino.net> <20041006234912.66bfbdcc.davem@davemloft.net> <20041007160532.60c3f26b@pirandello> <20041007112846.5c85b2d9.davem@davemloft.net> <20041007224422.1c1bea95@jack.colino.net> <20041007214505.GB31558@wotan.suse.de> <20041008090610.70d7e183@pirandello> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , "David S. Miller" , akpm@osdl.org, netdev@oss.sgi.com Return-path: To: Colin Leroy Content-Disposition: inline In-Reply-To: <20041008090610.70d7e183@pirandello> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Fri, Oct 08, 2004 at 09:06:10AM +0200, Colin Leroy wrote: > On 07 Oct 2004 at 23h10, Andi Kleen wrote: > > Hi, > > > > This patch should do that. It works OK for me, but I'd like it > > > checked before sent upstream... > > > > > > However, it doesn't fix the hang. it looks like this hang is really > > > coming from sungem. > > > > IMHO it's not needed. Taking xmit_lock is harmless even when > > the NETIF_F_LLTX flag is set. > > Should that be completely dropped, or is it still ok ? (I think > differenciating action based on hard_start_xmit status, that is, don't > goto repeat undefinitely when NETDEV_TX_BUSY, could be a good idea). > I mean, should I rework that patch, forget about it or leave it as-is? Well the purpose of the LLTX flag is to reduce serializing on the xmit_lock. If we take the lock anyway, that should be harmless as Andi says. So I'm afraid it looks to be a performance fix at best (which is a low priority here). Let's back burner it for now. > Concerning the hang, I see that Andrew has put my first patch, the one > checking for netif_carrier_ok(), in his tree. Is it an OK solution from > your (net dev hackers) point of view? It seems to be papering over a driver bug of some sort, which is not the way we like to fix things. -- Mathematics is the supreme nostalgia of our time.