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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 682B2C433EF for ; Wed, 23 Feb 2022 02:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235219AbiBWCNg (ORCPT ); Tue, 22 Feb 2022 21:13:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230453AbiBWCNf (ORCPT ); Tue, 22 Feb 2022 21:13:35 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5661436B62; Tue, 22 Feb 2022 18:13:07 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 902A161133; Wed, 23 Feb 2022 02:13:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95E3AC340E8; Wed, 23 Feb 2022 02:13:05 +0000 (UTC) Date: Tue, 22 Feb 2022 21:13:03 -0500 From: Steven Rostedt To: Luis Chamberlain Cc: Wei Xiao , mingo@redhat.com, keescook@chromium.org, yzaikin@google.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, young.liuyang@huawei.com, zengweilin@huawei.com, nixiaoming@huawei.com Subject: Re: [PATCH] ftrace: move sysctl_ftrace_enabled to ftrace.c Message-ID: <20220222211303.402e3e4d@rorschach.local.home> In-Reply-To: References: <20220223012311.134314-1-xiaowei66@huawei.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, 22 Feb 2022 17:52:59 -0800 Luis Chamberlain wrote: > On Wed, Feb 23, 2022 at 09:23:11AM +0800, Wei Xiao wrote: > > This moves ftrace_enabled to trace/ftrace.c. > > Hey Wei, thanks for you patch! > > This does not explain how this is being to help with maitenance as > otherwise this makes kernel/sysctl.c hard to maintain and we also tend > to get many conflicts. It also does not explain how all the filesystem > sysctls are not gone and that this is just the next step, moving slowly > the rest of the sysctls. Explaining this in the commit log will help > patch review and subsystem maintainers understand the conext / logic > behind the move. > > I'd be more than happy to take this if ftrace folks Ack. To avoid conflicts > I can route this through sysctl-next which is put forward in particular > to avoid conflicts across trees for this effort. Let me know. I'm fine with this change going through another tree. Acked-by: Steven Rostedt (Google) for your convenience. > > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > index f9feb197b2da..4a5b4d6996a4 100644 > > --- a/kernel/trace/ftrace.c > > +++ b/kernel/trace/ftrace.c > > @@ -7846,7 +7846,8 @@ static bool is_permanent_ops_registered(void) > > return false; > > } > > > > -int > > +#ifdef CONFIG_SYSCTL > > +static int > > Is the ifdef really needed? It was not there before, ie, does > ftrace not depend on sysctls? I don't see a direct relationship > but I do wonder if its implicit. I think because the function is now static, and that it now includes the structure itself, that the #ifdef is added. When I first saw it, I was a bit uncomfortable with adding more #ifdefs, but for this use case, I believe it's OK. > > > ftrace_enable_sysctl(struct ctl_table *table, int write, > > void *buffer, size_t *lenp, loff_t *ppos) > > { > > @@ -7889,3 +7890,22 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, > > mutex_unlock(&ftrace_lock); > > return ret; > > } > > + > > +static struct ctl_table ftrace_sysctls[] = { > > + { > > + .procname = "ftrace_enabled", > > + .data = &ftrace_enabled, > > + .maxlen = sizeof(int), > > + .mode = 0644, > > + .proc_handler = ftrace_enable_sysctl, > > + }, > > + {} > > +}; > > + > > +static int __init ftrace_sysctl_init(void) > > +{ > > + register_sysctl_init("kernel", ftrace_sysctls); > > + return 0; > > +} > > +late_initcall(ftrace_sysctl_init); > > +#endif > > There's other __init calls already on ftrace, would this be better > placed in one of them, and then have this be a no-op iff we determine > ftrace can be built without sysctls and then have a no-op for when > sysctls are disabled. I rather have the initcall here, as the other initcalls are special needs, and not generic functions. -- Steve