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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E545C55179 for ; Fri, 23 Oct 2020 13:29:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1370820FC3 for ; Fri, 23 Oct 2020 13:29:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603459795; bh=PIj6gL/WL9dtdsJ1vZSsuwhKFFiZ2/p2I3g1d0riLbg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=uqfguN0pPbTKnLLaLcg8xfOWiGk1Jvqwg7wo+vnGYRuleth3Kr4IQhmwXtW0Dqmzc iEF83adYUxwoGcTzyQqmQBIEMZplGZxTA0yeSf/h6FSrP7Q5pVwBKvjk7Tnwn/HWDE J+iTMtn1fQCvU9jXp0gbc6gJ9f4mvy8ErQP+hCXM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S464840AbgJWN3y (ORCPT ); Fri, 23 Oct 2020 09:29:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:44484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S374233AbgJWN3x (ORCPT ); Fri, 23 Oct 2020 09:29:53 -0400 Received: from localhost (unknown [176.167.163.208]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C2474208E4; Fri, 23 Oct 2020 13:29:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603459793; bh=PIj6gL/WL9dtdsJ1vZSsuwhKFFiZ2/p2I3g1d0riLbg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rw60FdcUJe+qyTPBmrOTcj5E3NoXurL8oWAxHIHPprbeTYuMCT+7Gs3n5RBd2Jy5W WRf+9+yliV+0OQ5yC5iaBH4gFNMCFFUYp3ljQpakpeC0v3npDWlVhd5N6nD37RbpdM ZmYSewtFRn5JthS5ZvXUueon8401r4+/gaYy2aI0= Date: Fri, 23 Oct 2020 15:29:50 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: Nitesh Narayan Lal , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, mtosatti@redhat.com, sassmann@redhat.com, jesse.brandeburg@intel.com, lihong.yang@intel.com, helgaas@kernel.org, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jiri@nvidia.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, lgoncalv@redhat.com, Thomas Gleixner Subject: Re: [PATCH v4 2/4] sched/isolation: Extend nohz_full to isolate managed IRQs Message-ID: <20201023132950.GA47962@lothringen> References: <20200928183529.471328-1-nitesh@redhat.com> <20200928183529.471328-3-nitesh@redhat.com> <20201023132505.GZ2628@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201023132505.GZ2628@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 23, 2020 at 03:25:05PM +0200, Peter Zijlstra wrote: > On Mon, Sep 28, 2020 at 02:35:27PM -0400, Nitesh Narayan Lal wrote: > > Extend nohz_full feature set to include isolation from managed IRQS. This > > So you say it's for managed-irqs, the feature is actually called > MANAGED_IRQ, but, AFAICT, it does *NOT* in fact affect managed IRQs. > > Also, as per Thomas' earlier points, managed-irqs are in fact perfectly > fine and don't need help at at... > > > is required specifically for setups that only uses nohz_full and still > > requires isolation for maintaining lower latency for the listed CPUs. > > > > Suggested-by: Frederic Weisbecker Ah and yes there is this tag :-p So that's my bad, I really thought this thing was about managed IRQ. The problem is that I can't find a single documentation about them so I'm too clueless on that matter. Thanks. > > Signed-off-by: Nitesh Narayan Lal > > --- > > kernel/sched/isolation.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > > index 5a6ea03f9882..9df9598a9e39 100644 > > --- a/kernel/sched/isolation.c > > +++ b/kernel/sched/isolation.c > > @@ -141,7 +141,7 @@ static int __init housekeeping_nohz_full_setup(char *str) > > unsigned int flags; > > > > flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | > > - HK_FLAG_MISC | HK_FLAG_KTHREAD; > > + HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ; > > > > return housekeeping_setup(str, flags); > > } > > -- > > 2.18.2 > >