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 C6294C4332F for ; Wed, 8 Nov 2023 12:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344575AbjKHMRq (ORCPT ); Wed, 8 Nov 2023 07:17:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344563AbjKHMRp (ORCPT ); Wed, 8 Nov 2023 07:17:45 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F5A91BCC for ; Wed, 8 Nov 2023 04:17:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bxii0z+MV2u3mm3xGKkp5XDR2KAZdmtoMUXNeRyR2Vc=; b=sDo3fsShfSwz0SN/P5BrWWtJd9 JRw+FoKOYrkp7NIvQrP5e/ghC93PoIQqRLZlTk19KhLZSho71hHyPS8JnZ89axJGfPWjeql7+sQpe xyAsAPFGreT0Ow4ego7fSiItijgxr9yxfx/Kf5eazE5Hds6iDizv6liF8DR2fawyjtHmgh7BlqrEF 87xMQno36eG6olJ8etZ2MaSAn+b1o5dKcWssFbIvXD3bvCvfi2QZbZ5VbPD8iuZjC40fzjtH0S7fD 7hXBjpFBbFjOpOOWQyq08rFXuAJGNqGPygPXnqUhTK0FWNLtA5BcI4aVPXkAS1zDQtukp/1M6zkIp xj1FIh+A==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1r0hU9-000vU8-0w; Wed, 08 Nov 2023 12:16:41 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 5E172300585; Wed, 8 Nov 2023 13:16:41 +0100 (CET) Date: Wed, 8 Nov 2023 13:16:41 +0100 From: Peter Zijlstra To: Ankur Arora Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, paulmck@kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, mingo@kernel.org, bristot@kernel.org, mathieu.desnoyers@efficios.com, geert@linux-m68k.org, glaubitz@physik.fu-berlin.de, anton.ivanov@cambridgegreys.com, mattst88@gmail.com, krypton@ulrich-teichert.org, rostedt@goodmis.org, David.Laight@aculab.com, richard@nod.at, mjguzik@gmail.com Subject: Re: [RFC PATCH 00/86] Make the kernel preemptible Message-ID: <20231108121641.GC4779@noisy.programming.kicks-ass.net> References: <20231107215742.363031-1-ankur.a.arora@oracle.com> <20231108085156.GD8262@noisy.programming.kicks-ass.net> <87bkc4lfxp.fsf@oracle.com> <20231108101330.GK3818@noisy.programming.kicks-ass.net> <87leb8ik6b.fsf@oracle.com> <20231108111415.GP8262@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231108111415.GP8262@noisy.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 08, 2023 at 12:14:15PM +0100, Peter Zijlstra wrote: > I would really suggest you start with transforming VOLUNTARY into the > LAZY thing, keep it as simple and narrow as possible. Possibly make it worse first, add LAZY as a fourth option, then show it makes VOLUNTARY redundant, kill that. > Once you've got that done, then you can try and argue that NONE makes no > sense and try and take it out. This also pushes out having to deal with the !PREEMPT archs until the very last moment. And once you're here, cond_resched() should be an obvious no-op function and you can go delete them. Anyway, as said, smaller steps more better. Nobody likes 86 patches in their inbox in the morning (or at any time really).