From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: Re: [PATCH net-next v6 01/11] net: sched: use rcu for action cookie update Date: Tue, 17 Jul 2018 13:46:42 -0700 Message-ID: References: <1530800673-12280-1-git-send-email-vladbu@mellanox.com> <1530800673-12280-2-git-send-email-vladbu@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Linux Kernel Network Developers , David Miller , Jamal Hadi Salim , Jiri Pirko , Alexei Starovoitov , Daniel Borkmann , Yevgeny Kliteynik , Jiri Pirko To: Vlad Buslov Return-path: Received: from mail-ed1-f65.google.com ([209.85.208.65]:37519 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730043AbeGQVVM (ORCPT ); Tue, 17 Jul 2018 17:21:12 -0400 Received: by mail-ed1-f65.google.com with SMTP id b10-v6so2343012eds.4 for ; Tue, 17 Jul 2018 13:46:48 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Jul 16, 2018 at 1:31 AM Vlad Buslov wrote: > > > On Fri 13 Jul 2018 at 21:51, Cong Wang wrote: > > On Fri, Jul 13, 2018 at 6:30 AM Vlad Buslov wrote: > >> > >> > >> On Fri 13 Jul 2018 at 03:52, Cong Wang wrote: > >> > On Thu, Jul 5, 2018 at 7:24 AM Vlad Buslov wrote: > >> >> > >> >> Implement functions to atomically update and free action cookie > >> >> using rcu mechanism. > >> > > >> > Without stating any reason..... Is this even a changelog? > >> > >> Yes, it is. > > > > What do you expect in a changelog generally? Repeating what > > your code does? Thanks but we don't even want to read any code > > unless the need of this code is reasonably justified. > > In my cover letter: > - Motivation for patchset is presented in first paragraph. > - Problems that prevent us from removing rtnl lock dependency are > described, problem 3 is about cookie pointer. > - In implementation section, point 3 presents solution for that > problem. Do you want to use cover letter as a changelog for all patches in your patchset? Seriously? :) Every patch is your patchset is unique, because you are not fixing a problem can be expressed by a pattern. Given how hard lockless is generally, probably you even can't find out a pattern. If you really do, I am happy to learn! > > > > > Can we at least agree you have no justification for this change > > in this changelog? Or you believe this patch is as trivial as > > a white space change which doesn't need a justification? > > Cong, from your last letter I understand that you want to have > justification specifically for using atomic operation in this particular > patch. I agree with you that I should have explained it in more details. > I found a lot of prior art for same or similar atomic ops usage for rcu > pointers(examples in my previous mail) and assumed it to be trivial, but > now I understand that I was wrong in this case. Thanks for having an agreement! I expect to see more detailed changelog in your future patches! :)