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 B543DC4167B for ; Sat, 10 Dec 2022 21:34:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229721AbiLJVeR (ORCPT ); Sat, 10 Dec 2022 16:34:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229475AbiLJVeP (ORCPT ); Sat, 10 Dec 2022 16:34:15 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86E2413FBA for ; Sat, 10 Dec 2022 13:34:14 -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 928C060A65 for ; Sat, 10 Dec 2022 21:34:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAD0FC433D2; Sat, 10 Dec 2022 21:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670708052; bh=uMhZzPEArHPhXyGDt+hkW/iaMUWCmUw8KwfG5lGSxk0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=f4k7RunYHoOoIMo0Nnm4+Gm2fCAZ+5uwbAouuV2lYslgbpCe3bBZYwLwnaQcoUAyK T7SuuzHPSWKBKtBPCWr8Y58J8PIBqAZpGBIHlE056CFemRYu7OLKHNug87HN343nOK 8GMNWtavLHDfXT/qDYKKfOVS1jQcmeae1fVGBHGlSPmAd884yIH+9QgdHyCCJB25Ef SjaOJynkaElif+29I5onxQHw6s5XgjzEXpB61h4Ja+QbjnuNYx3Cv+c6JZ/EGiYkDt WO45V4x0DTpF4RcmCLJcjsHqBXcN/0l0ap0mky+ExLGRa2ICD4ww33J2EfosKOzbEA hc/dgCWR69BzA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 7F9155C09A2; Sat, 10 Dec 2022 13:34:12 -0800 (PST) Date: Sat, 10 Dec 2022 13:34:12 -0800 From: "Paul E. McKenney" To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Masami Hiramatsu , Andrew Morton , Karol Herbst , Pekka Paalanen , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov Subject: Re: [for-next][PATCH 13/25] x86/mm/kmmio: Use rcu_read_lock_sched_notrace() Message-ID: <20221210213412.GF4001@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20221210135750.425719934@goodmis.org> <20221210135825.241167123@goodmis.org> <20221210174753.GD4001@paulmck-ThinkPad-P17-Gen-1> <20221210133425.4657985e@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221210133425.4657985e@gandalf.local.home> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 10, 2022 at 01:34:25PM -0500, Steven Rostedt wrote: > On Sat, 10 Dec 2022 09:47:53 -0800 > "Paul E. McKenney" wrote: > > > > Note, the preempt_disable() is still needed as it uses preempt_enable_no_resched(). > > > > > ... > > > Executable code can be the best form of comment. ;-) > > > > This does mess with preempt_count() redundantly, but the overhead from > > that should be way down in the noise. > > I was going to remove it, but then I realized that it would be a functional > change, as from the comment above, it uses "preempt_enable_no_resched(), > which there is not a rcu_read_unlock_sched() variant. If this happens often enough, it might be worth adding something like rcu_read_unlock_sched_no_resched(), but we clearly are not there yet. Especially not with a name like that! ;-) Thanx, Paul > > Acked-by: Paul E. McKenney > > Thanks! I'll add this to the commit. > > -- Steve