From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [PATCH RFC] netpoll: don't spin forever sending to stopped queues Date: Mon, 12 Jun 2006 15:53:10 -0500 Message-ID: <20060612205310.GU24227@waste.org> References: <44886381.9050506@goop.org> <20060608210702.GD24227@waste.org> <4488D9D6.6070205@goop.org> <20060611200407.GG24227@waste.org> <448DD556.6030705@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux Kernel Mailing List , netdev@vger.kernel.org Return-path: Received: from waste.org ([64.81.244.121]:59017 "EHLO waste.org") by vger.kernel.org with ESMTP id S932225AbWFLVDT (ORCPT ); Mon, 12 Jun 2006 17:03:19 -0400 To: Jeremy Fitzhardinge Content-Disposition: inline In-Reply-To: <448DD556.6030705@goop.org> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Jun 12, 2006 at 01:57:58PM -0700, Jeremy Fitzhardinge wrote: > Matt Mackall wrote: > >On Thu, Jun 08, 2006 at 07:15:50PM -0700, Jeremy Fitzhardinge wrote: > > > >>Here's a patch. I haven't tested it beyond compiling it, and I don't > >>know if it is actually correct. In this case, it seems pointless to > >>spin waiting for an even which will never happen. Should > >>netif_poll_disable() cause netpoll_send_skb() (or something) to not even > >>bother trying to send? netif_poll_disable seems mysteriously simple to > >>me. > >> > >> J > >> > > > >Did this work for you at all? > > > > No, it didn't appear to help; I get the same symptom. I think fix is > correct (in that its better than what was there before), but there's > probably more going on in my case. I haven't looked into it more deeply > yet. I suspect there's another netpoll code path which is spinning > forever on an XOFFed queue. > > >>When transmitting a skb in netpoll_send_skb(), only retry a limited > >>number of times if the device queue is stopped. > >> > > > >Where limited = once? > > > > No, it reuses the existing retry logic. It retries 20000 times with a > 50us pause between attempts, so up to a second. This seems excessive to > me; I don't know where those original numbers came from. I tried 5000 > retries, but it didn't make any difference to my case. Ahh, right. I forgot that I'd done that. Can you resend? -- Mathematics is the supreme nostalgia of our time.