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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 CDB4FC4727F for ; Thu, 1 Oct 2020 14:46:14 +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 66666207DE for ; Thu, 1 Oct 2020 14:46:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="IxjjKTGi"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="F3NVYP8t" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66666207DE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=TGJu4cwEhkUgKPqAxZ29q63YDxFGY9SYO3+8S64oOFw=; b=IxjjKTGipdqDi0X+Gs0BmePdY UuhhYyNCnXMy+t1cBvUGLPZhAmSci9X1weSXJzQCFaIEVWd3kL9pp/0K4/XKklaB7Fo1J8ztA2W5p 6Ej6F13PWfMpCMCoLXpGs5MfkE3LmZRUMmAqZVm9W7XITk0ApiJyi6cRNxWpJ2WPBSvc17H+BROvm 750OTQbxEEWVOQKwo1fYDpPMY+76hbh4276raec5I7MK7FGjoUvsB11qXwpEI8bU9fc/ZFYXaoXyv wCZAicABZmjhFrcVuaQnWgmZvOMaPdpjvqS91O0SjLDdC+kYt8Hvua+p2hu6E/uPf4qx2g3K9OdPj nu+OuNFCg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNzpM-0001tG-9z; Thu, 01 Oct 2020 14:45:00 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNzpK-0001sB-3x for linux-arm-kernel@lists.infradead.org; Thu, 01 Oct 2020 14:44:58 +0000 Received: from localhost (fla63-h02-176-172-189-251.dsl.sta.abo.bbox.fr [176.172.189.251]) (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 7CE5E207FB; Thu, 1 Oct 2020 14:44:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601563497; bh=dDC26q515F+Adnjw4FlkjfdULIOBLB9BDdSe3RhWuDU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=F3NVYP8tZU/Bi6llA5AaYGUeVhjR70aMs4gOeqYxm3k+PAJeYZ02dTbkx0lAK0kW+ G4oJv2DEjiAPRuxOp5vVP8gFXBP061GqDAJpK9vy08WczDaCm5fp77iUrSaZkwEqVv b6CtDaGlsU+Y48auonfo+Dsndbl96Q/J+bNpG4CY= Date: Thu, 1 Oct 2020 16:44:54 +0200 From: Frederic Weisbecker To: Alex Belits Subject: Re: [PATCH v4 10/13] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Message-ID: <20201001144454.GB6595@lothringen> References: <04be044c1bcd76b7438b7563edc35383417f12c8.camel@marvell.com> <5acf7502c071c0d1365ba5e5940e003a7da6521f.camel@marvell.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5acf7502c071c0d1365ba5e5940e003a7da6521f.camel@marvell.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201001_104458_250639_F80F8836 X-CRM114-Status: GOOD ( 20.21 ) 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" , "catalin.marinas@arm.com" , "peterz@infradead.org" , Prasun Kapoor , "linux-kernel@vger.kernel.org" , "rostedt@goodmis.org" , "davem@davemloft.net" , "netdev@vger.kernel.org" , "linux-api@vger.kernel.org" , "tglx@linutronix.de" , "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 Wed, Jul 22, 2020 at 02:57:33PM +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 6e4cd8459f05..2f82a6daf8fc 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 is it ordering? > + if (!tick_nohz_full_cpu(cpu) || task_isolation_on_cpu(cpu)) > return; You can't simply ignore an IPI. There is always a reason for a nohz_full CPU to be kicked. Something triggered a tick dependency. It can be posix cpu timers for example, or anything. > > irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu); > -- > 2.26.2 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel