From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: Re: [Patch net-next v3 0/3] net_sched: reflect tx_queue_len change for pfifo_fast Date: Sun, 28 Jan 2018 21:57:11 -0800 Message-ID: References: <20180126022624.20442-1-xiyou.wangcong@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Linux Kernel Network Developers To: John Fastabend Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:39182 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042AbeA2F5c (ORCPT ); Mon, 29 Jan 2018 00:57:32 -0500 Received: by mail-pg0-f67.google.com with SMTP id w17so3636353pgv.6 for ; Sun, 28 Jan 2018 21:57:32 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Sun, Jan 28, 2018 at 9:35 PM, John Fastabend wrote: > On 01/25/2018 06:26 PM, Cong Wang wrote: >> This pathcset restores the pfifo_fast qdisc behavior of dropping >> packets based on latest dev->tx_queue_len. Patch 1 introduces >> a helper, patch 2 introduces a new Qdisc ops which is called when >> we modify tx_queue_len, patch 3 implements this ops for pfifo_fast. >> >> Please see each patch for details. >> > > Overall this series is better than what we have at the moment, but > a better fix would preallocate the memory, to avoid ENOMEM errors, I am not against for better ENOMEM error handling, but I still have to remind you that attach_one_default_qdisc() doesn't handle it either. Since no one complained about it, why this one is so special? > and add a ptr_ring API to use the preallocated buffers. What ptr_ring API could cure netdev tx queues problem here? Looks like you still don't understand the problem here. > > We have time (its only in net-next) so lets do the complete fix > rather than this series IMO. > Why not just accept this and complete the error handling later given the fact that I already add a TODO? IOW, why it is now?