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 7C95BC433F5 for ; Mon, 21 Feb 2022 18:51:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232503AbiBUSwP (ORCPT ); Mon, 21 Feb 2022 13:52:15 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:34794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232418AbiBUSvk (ORCPT ); Mon, 21 Feb 2022 13:51:40 -0500 Received: from mail1.wrs.com (unknown-3-146.windriver.com [147.11.3.146]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81451D7C for ; Mon, 21 Feb 2022 10:51:16 -0800 (PST) Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.corp.ad.wrs.com [147.11.82.252]) by mail1.wrs.com (8.15.2/8.15.2) with ESMTPS id 21LIKXlI027173 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 21 Feb 2022 10:20:34 -0800 Received: from ala-exchng01.corp.ad.wrs.com (147.11.82.252) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.12; Mon, 21 Feb 2022 10:20:33 -0800 Received: from yow-pgortmak-d4.wrs.com (128.224.56.60) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server id 15.1.2242.12 via Frontend Transport; Mon, 21 Feb 2022 10:20:31 -0800 From: Paul Gortmaker To: , Frederic Weisbecker , Peter Zijlstra CC: Paul Gortmaker , Ingo Molnar , Nicholas Piggin , "Paul E . McKenney" , Thomas Gleixner Subject: [PATCH v2 0/2] sched/nohz: disallow non-existent cores from nohz-full Date: Mon, 21 Feb 2022 13:20:07 -0500 Message-ID: <20220221182009.1283-1-paul.gortmaker@windriver.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a rebase and retest of two fixes I'd sent earlier[1]. The rebase is required due to conflicts in my patch #1 and where Frederic updated the unwind code in housekeeping_setup in his series[2] and that series is now in sched/core of tip[3]. So this update is against a baseline of ed3b362d54f0 found in sched/core as "sched/isolation: Split housekeeping cpumask per isolation features" in tip. Changes amount to "return 0" ---> "goto out_free" and adding a nod to PaulM's observation that nohz_full w/o a cpuset is coming someday into the commit log. [1] https://lore.kernel.org/all/20211206145950.10927-1-paul.gortmaker@windriver.com/ [2] https://lore.kernel.org/all/20220207155910.527133-1-frederic@kernel.org/ [3] git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git ----- Original v1 text follows ----- A couple months back I sent a fix to reconcile rcu_nocbs= input restrictions with nohz_full= input restrictions; with the latter being more restrictive than the former. However, in relaxing the nohz_full restrictions, I made it possible to boot with a nohz_full= parameter that contains nothing but nonexistent and not-possible cores - which will trigger a WARN. This fixes the original reconcile commit by explicitly coding our allowed values just like RCU does, and changes the WARN_ON to a WARN_ON_ONCE, since it needlessly rendered the machine unusable. --- Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Nicholas Piggin Cc: Paul E. McKenney Cc: Thomas Gleixner Paul Gortmaker (2): sched/isolation: really align nohz_full with rcu_nocbs tick/nohz: WARN_ON --> WARN_ON_ONCE to prevent console saturation kernel/sched/isolation.c | 11 +++++++++++ kernel/time/tick-sched.c | 2 +- 2 files changed, 12 insertions(+), 1 deletion(-) -- 2.17.1