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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6F31BD29C2F for ; Mon, 19 Jan 2026 14:26:24 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4dvt730KJlz3bfY; Tue, 20 Jan 2026 01:26:23 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2001:8b0:10b:1:d65d:64ff:fe57:4e05" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1768832783; cv=none; b=Qg5Mz8Hc6q90Q76P8ZfSoLmebWq1jNyc6EAvQMbTOu8hpqiMOlM8T6yB6uOqDAV63my8LT3xLLB2ssx+sC6KtJYBruuxzK9RbvnNWemCBIztxI51I4+OWp4RpcrKM4701zquhBCmvSRts3bHvMSRnH2VwiMNjdMhTzzHgKM7bUi5E5zLJlZjIsRKI0I+azGMQIF1tLDfr20AzICSqvkQnmSx9Rs0jRPp2XKdHZpBp6QQH6OS7ZoCFvPmWPHIHi8uCsa5m/7iLiAOUoLU4vIdXcY0xQ8XdnifYIqGaUkh3wodLnQTjiJbYdPZszCef4t55RFQtYPgksFDanOXC6TGkg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1768832783; c=relaxed/relaxed; bh=J7YR6Ss4GR1p+SXEIbKvrV+9SeOL7XVCLDPQxRbp/9Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XIG3Pwgw/RKv7UlE8teRu3OIbH/jVv5dSgOUqDQ2dXXZOhzPWRJIN8P4DbZPQd+pt5IBs4QAPEbJKT0loC+iDMrKrDQYne+XaDblNSbKyUYPChuD2aMhOzRmD5T2VUNh5qFwxrdXcrE3QElPhx89kYBpaI2o4thboAv2bBo0BSVSJxEQEmSnbr1RdmKLmBLPbIaB91rCKaZUM2JVr3dWNmMrdfGixuS8+t3Vn+gd//G38oJDt6wBSA1331PcUP4/x1wHUR7XqsaM+yn0juVVTSmCd4fAakR7f2ahvGZ2YTHuJImWvOJpjscbxExFqiQo7unzczMAcWO0dXnNWnOulQ== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=infradead.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=phVpzmPF; dkim-atps=neutral; spf=none (client-ip=2001:8b0:10b:1:d65d:64ff:fe57:4e05; helo=desiato.infradead.org; envelope-from=peterz@infradead.org; receiver=lists.ozlabs.org) smtp.mailfrom=infradead.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=phVpzmPF; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2001:8b0:10b:1:d65d:64ff:fe57:4e05; helo=desiato.infradead.org; envelope-from=peterz@infradead.org; receiver=lists.ozlabs.org) Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4dvt7058Cfz3bf8 for ; Tue, 20 Jan 2026 01:26:20 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=J7YR6Ss4GR1p+SXEIbKvrV+9SeOL7XVCLDPQxRbp/9Q=; b=phVpzmPFu1Lg5Wwsu+BOkmfOW+ 7MEiiANgQ2k/WAjssImTBsBtsTReEql3LfWeR3eFCTJMcXjNSQuIO7LbmizlIxbjd7SrLLSKCcBSp aDO/nN6wrUdvONoFpb1boJnDyyb9lER3VTnG9922Knms3+B9j6HFUVGinLdmiEyvhWAyM1emPfId0 3ejQrUhO0sHyp8rUFpwu26JS3ZZq0CPSKVHkIzEgF64hdM1+c+1BQTsyQUJrF/KtLBbP6GFbLLb2j Jm6wiXTO8fSdUEnK92SIQIyQQDwiIUBCAg2WEYqWULtN4+kC03qtQtM6yeOYdsHHp/DqXmbnbADUG Oa7LNwWA==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vhqCm-0000000CGLf-3TCN; Mon, 19 Jan 2026 14:26:09 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id DA8703006CD; Mon, 19 Jan 2026 15:26:07 +0100 (CET) Date: Mon, 19 Jan 2026 15:26:07 +0100 From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , "Christophe Leroy (CS GROUP)" , "Rafael J. Wysocki" , Alexander Gordeev , Anna-Maria Behnsen , Ben Segall , Boqun Feng , Christian Borntraeger , Dietmar Eggemann , Heiko Carstens , Ingo Molnar , Jan Kiszka , Joel Fernandes , Juri Lelli , Kieran Bingham , Madhavan Srinivasan , Mel Gorman , Michael Ellerman , Neeraj Upadhyay , Nicholas Piggin , "Paul E . McKenney" , Steven Rostedt , Sven Schnelle , Thomas Gleixner , Uladzislau Rezki , Valentin Schneider , Vasily Gorbik , Vincent Guittot , Viresh Kumar , Xin Zhao , linux-pm@vger.kernel.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 06/15] tick/sched: Unify idle cputime accounting Message-ID: <20260119142607.GG830229@noisy.programming.kicks-ass.net> References: <20260116145208.87445-1-frederic@kernel.org> <20260116145208.87445-7-frederic@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260116145208.87445-7-frederic@kernel.org> On Fri, Jan 16, 2026 at 03:51:59PM +0100, Frederic Weisbecker wrote: > +#ifdef CONFIG_NO_HZ_COMMON > +void kcpustat_dyntick_start(void) > +{ > + if (!vtime_generic_enabled_this_cpu()) { > + vtime_dyntick_start(); > + __this_cpu_write(kernel_cpustat.idle_dyntick, 1); > + } > +} Why don't we need to make sure steal time is up-to-date at this point? > +void kcpustat_dyntick_stop(void) > +{ > + if (!vtime_generic_enabled_this_cpu()) { > + __this_cpu_write(kernel_cpustat.idle_dyntick, 0); > + vtime_dyntick_stop(); > + steal_account_process_time(ULONG_MAX); > + } > +} > +#endif /* CONFIG_NO_HZ_COMMON */