From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B61C9C10F29 for ; Mon, 9 Mar 2020 20:18:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D32B2253D for ; Mon, 9 Mar 2020 20:18:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726623AbgCIUSS (ORCPT ); Mon, 9 Mar 2020 16:18:18 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38821 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726121AbgCIUSR (ORCPT ); Mon, 9 Mar 2020 16:18:17 -0400 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jBOqC-0003vj-3C; Mon, 09 Mar 2020 20:17:32 +0000 Date: Mon, 9 Mar 2020 21:17:29 +0100 From: Christian Brauner To: "Eric W. Biederman" Cc: Bernd Edlinger , Kees Cook , Jann Horn , Jonathan Corbet , Alexander Viro , Andrew Morton , Alexey Dobriyan , Thomas Gleixner , Oleg Nesterov , Frederic Weisbecker , Andrei Vagin , Ingo Molnar , "Peter Zijlstra (Intel)" , Yuyang Du , David Hildenbrand , Sebastian Andrzej Siewior , Anshuman Khandual , David Howells , James Morris , Greg Kroah-Hartman , Shakeel Butt , Jason Gunthorpe , Christian Kellner , Andrea Arcangeli , Aleksa Sarai , "Dmitry V. Levin" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "stable@vger.kernel.org" , "linux-api@vger.kernel.org" Subject: Re: [PATCH v2 3/5] exec: Move cleanup of posix timers on exec out of de_thread Message-ID: <20200309201729.yk5sd26v4bz4gtou@wittgenstein> References: <87a74xi4kz.fsf@x220.int.ebiederm.org> <87r1y8dqqz.fsf@x220.int.ebiederm.org> <87tv32cxmf.fsf_-_@x220.int.ebiederm.org> <87v9ne5y4y.fsf_-_@x220.int.ebiederm.org> <87eeu25y14.fsf_-_@x220.int.ebiederm.org> <20200309195909.h2lv5uawce5wgryx@wittgenstein> <877dztz415.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <877dztz415.fsf@x220.int.ebiederm.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 09, 2020 at 03:06:46PM -0500, Eric W. Biederman wrote: > Christian Brauner writes: > > > On Sun, Mar 08, 2020 at 04:36:55PM -0500, Eric W. Biederman wrote: > >> > >> These functions have very little to do with de_thread move them out > >> of de_thread an into flush_old_exec proper so it can be more clearly > >> seen what flush_old_exec is doing. > >> > >> Signed-off-by: "Eric W. Biederman" > >> --- > >> fs/exec.c | 10 +++++----- > >> 1 file changed, 5 insertions(+), 5 deletions(-) > >> > >> diff --git a/fs/exec.c b/fs/exec.c > >> index ff74b9a74d34..215d86f77b63 100644 > >> --- a/fs/exec.c > >> +++ b/fs/exec.c > >> @@ -1189,11 +1189,6 @@ static int de_thread(struct task_struct *tsk) > > > > While you're cleaning up de_thread() wouldn't it be good to also take > > the opportunity and remove the task argument from de_thread(). It's only > > ever used with current. Could be done in one of your patches or as a > > separate patch. > > How does that affect the code generation? The same way renaming "tsk" to "me" does. > > My sense is that computing current once in flush_old_exec is much > better than computing it in each function flush_old_exec calls. > I remember that computing current used to be not expensive but > noticable. > > For clarity I can see renaming tsk to me. So that it is clear we are > talking about the current process, and not some arbitrary process. For clarity since de_thread() uses "tsk" giving the impression that any task can be dethreaded while it's only ever used with current. It's just a suggestion since you're doing the rename tsk->me anyway it would fit with the series. You do whatever you want though. (I just remember that the same request was made once to changes I did: Don't pass current as arg when it's the only task passed.)