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 D3883C433FE for ; Wed, 27 Oct 2021 21:21:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDB7D610EA for ; Wed, 27 Oct 2021 21:21:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231161AbhJ0VYT (ORCPT ); Wed, 27 Oct 2021 17:24:19 -0400 Received: from unknown-3-146.windriver.com ([147.11.3.146]:10400 "EHLO mail1.wrs.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S241252AbhJ0VXD (ORCPT ); Wed, 27 Oct 2021 17:23:03 -0400 X-Greylist: delayed 2057 seconds by postgrey-1.27 at vger.kernel.org; Wed, 27 Oct 2021 17:22:58 EDT Received: from mail.windriver.com (mail.wrs.com [147.11.1.11]) by mail1.wrs.com (8.15.2/8.15.2) with ESMTPS id 19RKhmKw001394 (version=TLSv1.1 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Wed, 27 Oct 2021 13:43:54 -0700 Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.corp.ad.wrs.com [147.11.82.252]) by mail.windriver.com (8.15.2/8.15.2) with ESMTPS id 19RKhUEV028289 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 27 Oct 2021 13:43:36 -0700 (PDT) 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; Wed, 27 Oct 2021 13:43:30 -0700 Received: from yow-pgortmak-d1.wrs.com (128.224.56.57) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server id 15.1.2242.12 via Frontend Transport; Wed, 27 Oct 2021 13:43:29 -0700 From: Paul Gortmaker To: CC: Paul Gortmaker , Ingo Molnar , Steven Rostedt , Thomas Gleixner , Peter Zijlstra , Josh Triplett , "Paul E . McKenney" , "Frederic Weisbecker" , Valentin Schneider Subject: [PATCH 0/2] bind rcu offload (nohz_full/isolation) into cpuset Date: Wed, 27 Oct 2021 16:43:17 -0400 Message-ID: <20211027204319.22697-1-paul.gortmaker@windriver.com> X-Mailer: git-send-email 2.15.0 MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org One of the earlier pre-mainline RCU nocb patchsets had a temporary sysfs knob in /sys/devices/system/cpu/cpu*/hotplug/nocb for testing[1]. That not-for-merge commit from Frederic said: This is only intended for those who want to test this patchset. The real interfaces will be cpuset/isolation and rcutorture. We've had rcutorture as the one and only mainline user of nocb toggle for a while now[2], and so I thought I'd take a crack at what Frederic had in mind for cpuset with some code vs. asking 100 random questions. Note that I intentionally didn't Cc any cgroup/cpuset people (yet), since at this point this is only my guess on what things were to look like based on a single sentence fragment. So this is really early "Not-for-Merge", but truly just RFC -- to start a conversation. It won't be really useful until we adjust tick/housekeeping in addition to nocb, but I think we can develop the interface in parallel to that? And maybe use this to expand testing at the same time if it is layered on top of those future work/patchsets? I don't know... We'll also have to look at corner cases - like whether we want to treat the root cpuset differently; whether we want to sync boot arg values with the cpuset's initial isol flag value, whether we un-isolate cores when an isolation cpuset is rmdir/removed, etc etc. But as a proof of concept, it "works" as can be seen in the 2nd commit. Paul. -- Cc: Ingo Molnar Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Josh Triplett Cc: Paul E. McKenney Cc: Frederic Weisbecker Cc: Valentin Schneider [1] https://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git/commit/?h=rcu/nocb&id=6abe8408307e part of https://lwn.net/Articles/820544/ https://lwn.net/Articles/832031/ <------ v2 https://lwn.net/Articles/835039/ <------ v3 https://lwn.net/Articles/837128/ <------ v4 [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d97b078182406 Paul Gortmaker (2): sched: isolation: cpu isolation handles for cpuset cpuset: add binding to CPU isolation include/linux/sched/isolation.h | 4 ++++ kernel/cgroup/cpuset.c | 42 +++++++++++++++++++++++++++++++++++++++++ kernel/sched/isolation.c | 22 +++++++++++++++++++++ 3 files changed, 68 insertions(+) -- 2.15.0