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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36FB7C433F5 for ; Wed, 10 Nov 2021 05:44:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16B036113E for ; Wed, 10 Nov 2021 05:44:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229931AbhKJFrl (ORCPT ); Wed, 10 Nov 2021 00:47:41 -0500 Received: from mout.gmx.net ([212.227.15.18]:37137 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229572AbhKJFrj (ORCPT ); Wed, 10 Nov 2021 00:47:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1636523083; bh=eQJvjyDXd9/NnjKwFms2Jb3Wg/GnVPYrpBreiYi5at4=; h=X-UI-Sender-Class:Subject:From:To:Cc:Date:In-Reply-To:References; b=D5pCkv3YQ6Z/is9CV0HJOpaPaoCUs6ddDd+eLTTR7XJIj4eDnX68C3G/EeuPap48J lZlSSdWDBrbR9G2tZWP83NAsPpPHnWStYzdXYGeU59Po99QVk35C0WOVe2zkMR/ji7 0sRRMk4dKHXQXRO8hrNPEUqetYANjZeKkK/rQSxg= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from homer.fritz.box ([212.114.172.107]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1M2wL0-1mjZPr0Z6C-003ObQ; Wed, 10 Nov 2021 06:44:43 +0100 Message-ID: Subject: Re: [PATCH] sched: Tweak default dynamic preempt mode selection From: Mike Galbraith To: Valentin Schneider , Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar Date: Wed, 10 Nov 2021 06:44:42 +0100 In-Reply-To: <87k0hgswpf.mognet@arm.com> References: <20211105104035.3112162-1-valentin.schneider@arm.com> <20211109102502.GA288354@lothringen> <87k0hgswpf.mognet@arm.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:VaQOTFhL3R7uxCD4hLqyvBcxePP1UhGUhCWjnB5SseE6Jll3PaB om66+vmVV5iIt/RbHZ1jyoB9Z7ieyQS2lf0/S7h2x5Do7CV0CvaK8va8PBzGE+9sPlVlKCt jaK3UdcvEU1fWv9crJXcvOyyR3AZDLYNWiFt2WKSJ40muMjNFj+9cCPxcxTIxvhIFm4OyfH NlVLlKxR/02MOlQw9jM0A== X-UI-Out-Filterresults: notjunk:1;V03:K0:fzV3ocTrGFM=:e1f13SHqPGrYNAi8mDgqDt Za9x0C6CWMgWPmMqgO5hEBVUDfkD7Y7WOHjT1vNSNYK8Ac/V8dxNQ5qJx7rRraohWNPgez6Fy wEJz9hfcmttO1l9jS0Ki1eE62le+LuxG9XFX9dWPLey3zND7W/Pjw2IehxvMoEWkON3j+fhcS O8hULYoN3ATaknQQktcoDccKUAKUj+5WrFXA8bgKTZs0N0fZBxZhjAYNJ+601zd07KUAVLKmr jJyU01zWMO5hbTZVogxx1CHFQfuOQblyX5T3T12prQP6rvqr9uVKzX0fjUfTB+G+svy2B2VZ+ 8ANL8CgyO/TSMehM6pt0+ERe0+9Ceomz3pDRc8v+rhpdjDapperiuVm/wtIS9eCj+Bq/r13Ws rWLwmUtrUMaJHNT561YMkHcLJmDLgLGDTfo+tbSNBu49lWlvClCnUeoMVnRLPZm+mmnLAPAsT wou3kxmhhkyhqpFid0G9VO+2JWFteoBTMitpdBZT78AVU6vym4eQbibKoI0nmhBSCax4Bwp8G SfgRJ67Ri83DC/xCYzR4yFRiWu90o8xa5/RBbPk+6UmVnDPpC7XRslAKOZOo3wpDUjstp/hvM txPFDBLtrSMTocfdbuT3/3zD/rFSHDeNo5PnE1aowAQniDrNe5sPGV6BHexP8iNVncjJGq8+p 72sAJqDnKWxA07qp4GxyIRdkixpsblQ7MRPMkq5GZsIkHZOSyZ9X582nKVQHCz8W3cjKW9vjf 0NL7YOkSDx2DyQlnObYp4SyQ8TbiOILmap0yCv/ljPF5utk2KR9ms3y4FlwXuqDosXgMAteEX FldoC6F1z0C88HxUIoUi/Go5d7TPMYOGYzr0CMHZPjSpp05hx2UxlqP7PXCZP9jSHTbmS0bx4 Kkj5oPI09eKdgc4bUC6ZkaQYt8vMQyHDPuviaKd5xhZpDkfxeVZehIG3Au/FL+mWrviMIgLuH jOB+aWiplA99raihLPGF+OM0GiwP8FGeb8vHZL78rdvHQDSqWVdlCoBszc0vPNtif4oJi5CLN Q7xoUNzDjDx5OpcS/c0hNcWKsotIj4wB9hAjcAR6NUZFshgbnA+ul3YYRO+YbZzghCd59yKjR dZfqi4QYcnVLlc= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2021-11-10 at 00:03 +0000, Valentin Schneider wrote: > On 09/11/21 11:25, Frederic Weisbecker wrote: > > On Fri, Nov 05, 2021 at 10:40:35AM +0000, Valentin Schneider wrote: > > > @@ -75,17 +86,6 @@ config PREEMPT_RT > > > > > > =C2=A0endchoice > > > > > > -config PREEMPT_NONE > > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0bool > > > - > > > -config PREEMPT_VOLUNTARY > > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0bool > > > - > > > -config PREEMPT > > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0bool > > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0select PREEMPTION > > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0select UNINLINE_SPIN_UNLO= CK if !ARCH_INLINE_SPIN_UNLOCK > > > - > > > =C2=A0config PREEMPT_COUNT > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 bool > > > > This must be breaking cond_resched() and might_resched() definitions. > > > > Since CONFIG_PREEMPT_NONE, CONFIG_PREEMPT_VOLUNTARY and CONFIG_PREEMPT= aren't too widely > > spread around within ifdefferies, you can: > > > > 1) Rename CONFIG_PREEMPT_NONE to CONFIG_PREEMPT_NONE_STATIC > > =C2=A0=C2=A0 Rename CONFIG_PREEMPT_VOLUNTARY to CONFIG_PREEMPT_VOLUNTA= RY_STATIC > > =C2=A0=C2=A0 Rename CONFIG_PREEMPT to CONFIG_PREEMPT_STATIC > > > > 2) Keep the old CONFIG_PREEMPT_NONE, CONFIG_PREEMPT_VOLUNTARY, > > =C2=A0=C2=A0 CONFIG_PREEMPT around for compatibility and make them sel= ect their > > =C2=A0=C2=A0 corresponding BEHAVIOUR entries. > > > > Damn, I was too zealous on my inbox clearing and skipped that one, sorry= ! > (and ofc in the meantime Mike and I went down separate rabbit holes). > > The old CONFIG_PREEMPT* would have to remain somewhere in the menu entry > (e.g. "legacy" preemption mode selection?), but other than that it seems= to > work with this kind of structure: > > choice > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 prompt "Preemption Model" > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 default PREEMPT_BEHAVIOUR if = PREEMPT > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 default PREEMPT_VOLUNTARY_BEH= AVIOUR if PREEMPT_VOLUNTARY > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 default PREEMPT_NONE_BEHAVIOU= R > > This however doesn't solve Mike's concern wrt deselecting PREEMPT_RT to > flip PREEMPT_DYNAMIC and vice versa... OTOH it's not quite here/now relevant, whereas your config woes are... -Mike