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 9B7A9C4332F for ; Tue, 8 Nov 2022 12:24:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234234AbiKHMY4 (ORCPT ); Tue, 8 Nov 2022 07:24:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234231AbiKHMYq (ORCPT ); Tue, 8 Nov 2022 07:24:46 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13A874FFA7 for ; Tue, 8 Nov 2022 04:24:43 -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 A375561503 for ; Tue, 8 Nov 2022 12:24:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D24AC433D6; Tue, 8 Nov 2022 12:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667910282; bh=DIgP7uPQKj0lwA2YB9gPgcW4fnH+W7WgHIsSh/Cgwt8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XLzezLU97ctWJIIz/k8E9MMSMNTMfFqBpXh6PJaunmdTM/169PtNdVX+ufSSaZzIL L/ueI4AhoprqGnU4JiKPeAYGKavd91uo+Lu6esW20CEeaV0JaOpUzE1c7TEd0Trj2j bBnMk0J4aBRAV5/EY+HzNhE/hq9oFMKkXk3zMQf8= Date: Tue, 8 Nov 2022 13:24:39 +0100 From: Greg Kroah-Hartman To: Vishal Chourasia Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, mingo@redhat.com, vincent.guittot@linaro.org, vschneid@redhat.com, srikar@linux.vnet.ibm.com, sshegde@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, ritesh.list@gmail.com, aneesh.kumar@linux.ibm.com Subject: Re: sched/debug: CPU hotplug operation suffers in a large cpu systems Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 08, 2022 at 03:30:46PM +0530, Vishal Chourasia wrote: > > Thanks Greg & Peter for your direction. > > While we pursue the idea of having debugfs based on kernfs, we thought about > having a boot time parameter which would disable creating and updating of the > sched_domain debugfs files and this would also be useful even when the kernfs > solution kicks in, as users who may not care about these debugfs files would > benefit from a faster CPU hotplug operation. Ick, no, you would be adding a new user/kernel api that you will be required to support for the next 20+ years. Just to get over a short-term issue before you solve the problem properly. If you really do not want these debugfs files, just disable debugfs from your system. That should be a better short-term solution, right? Or better yet, disable SCHED_DEBUG, why can't you do that? thanks, greg k-h