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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 9411EC4361B for ; Mon, 7 Dec 2020 11:59:46 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B21F2333F for ; Mon, 7 Dec 2020 11:59:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B21F2333F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jRsID60SU4WAIUwuOpGLmnzgdOmp8aO42YSOpmQEZJw=; b=rUADh9KgwjDfG9v84uSRENxRl 4TQlhIAlde5Ji1Lev5WLJ6a9W4bMa2sCAwQfamaDPmvb1oW7b5iSK7ubeM3dK2WX7NDLtBiAmpdt2 dpndnYjJby/aq/DVdCYQVZjVvG/nqiY9NUO/SHydzPI7W0O8sCSTzDeNAYivJPifM2cqD8LXL1wJE lg5Ts2JRAQ+9KfBAEIKxh/x1EYQt8fc0hQ1f1WVcQfc3opqCEe/biPoleuwdW97ky+eWRTifRg6/K JOcFK9RHBIUN4xx374XGQc91hZ64POD9PlGehy/I6s/QUR0rVj4AL7/aWyXsWJYnGukzeGiVL6Jl/ DgZ6Cv/SQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmFA7-0004EL-R5; Mon, 07 Dec 2020 11:58:39 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kmF9p-00048k-Hk for linux-arm-kernel@lists.infradead.org; Mon, 07 Dec 2020 11:58:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B28BF1042; Mon, 7 Dec 2020 03:58:19 -0800 (PST) Received: from C02TD0UTHF1T.local (unknown [10.57.27.106]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 771DD3F718; Mon, 7 Dec 2020 03:58:15 -0800 (PST) Date: Mon, 7 Dec 2020 11:58:12 +0000 From: Mark Rutland To: Alex Belits Subject: Re: [EXT] Re: [PATCH v5 7/9] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Message-ID: <20201207115812.GC18365@C02TD0UTHF1T.local> References: <8d887e59ca713726f4fcb25a316e1e932b02823e.camel@marvell.com> <76ed0b222d2f16fb5aebd144ac0222a7f3b87fa1.camel@marvell.com> <20201202142033.GD66958@C02TD0UTHF1T.local> <0c56e388c18187874ff23167d6927fed97e106b7.camel@marvell.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0c56e388c18187874ff23167d6927fed97e106b7.camel@marvell.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201207_065821_831682_D0B79A53 X-CRM114-Status: GOOD ( 25.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linux-arch@vger.kernel.org" , "nitesh@redhat.com" , "pauld@redhat.com" , "catalin.marinas@arm.com" , "peterz@infradead.org" , Prasun Kapoor , "frederic@kernel.org" , "mtosatti@redhat.com" , "linux-kernel@vger.kernel.org" , "rostedt@goodmis.org" , "davem@davemloft.net" , "leon@sidebranch.com" , "netdev@vger.kernel.org" , "peterx@redhat.com" , "trix@redhat.com" , "tglx@linutronix.de" , "linux-api@vger.kernel.org" , "will@kernel.org" , "mingo@kernel.org" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Dec 04, 2020 at 12:54:29AM +0000, Alex Belits wrote: > > On Wed, 2020-12-02 at 14:20 +0000, Mark Rutland wrote: > > External Email > > > > ------------------------------------------------------------------- > > --- > > On Mon, Nov 23, 2020 at 05:58:22PM +0000, Alex Belits wrote: > > > From: Yuri Norov > > > > > > For nohz_full CPUs the desirable behavior is to receive interrupts > > > generated by tick_nohz_full_kick_cpu(). But for hard isolation it's > > > obviously not desirable because it breaks isolation. > > > > > > This patch adds check for it. > > > > > > Signed-off-by: Yuri Norov > > > [abelits@marvell.com: updated, only exclude CPUs running isolated > > > tasks] > > > Signed-off-by: Alex Belits > > > --- > > > kernel/time/tick-sched.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > > > index a213952541db..6c8679e200f0 100644 > > > --- a/kernel/time/tick-sched.c > > > +++ b/kernel/time/tick-sched.c > > > @@ -20,6 +20,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -268,7 +269,8 @@ static void tick_nohz_full_kick(void) > > > */ > > > void tick_nohz_full_kick_cpu(int cpu) > > > { > > > - if (!tick_nohz_full_cpu(cpu)) > > > + smp_rmb(); > > > > What does this barrier pair with? The commit message doesn't mention > > it, > > and it's not clear in-context. > > With barriers in task_isolation_kernel_enter() > and task_isolation_exit_to_user_mode(). Please add a comment in the code as to what it pairs with. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel