From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9781733ADA0; Mon, 19 Jan 2026 12:54:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768827253; cv=none; b=ZWcle/8VIHl7CgK6a4BbB3OVy6e/BpiEo03jwxikYFUeKP2R9IsBrJlzFtOXdqbwhzmBjLj6ee+1pyI9fSlJX/guy3ryn/lTavZGNPMxPFOsRWfk59EwjTp12DMKnatTyDkQ1JpcZQGrvQHMHsefBzui6qvuqT+6dqgajI2nigk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768827253; c=relaxed/simple; bh=6fcd//7R70x07guaxNai+ickFmIDLdc1YPzmFaHHm4Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=urDFqYNI0QaVs+gsxXWhNmim4iX17ZSaqVMXs1Ui4+dSDEsF0660L/mrTs6SP4WMTIQvYPx3IZhReajiVxNWiZt0gdVtDTKsOx/ukPNBhkHRrSXiMDtKf2TbTe2A5F93dAfvgrDyUWKdsdB0e7xZDHLv/nn65UExLXcsBjVsAxk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=vJqhYbqP; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="vJqhYbqP" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=kMRIv+5PhMX2w16KgQw853ivOAJWaId7zAyJ1dkF8Fs=; b=vJqhYbqP6wfcMsUoLbLcFpjsau pI7huCZ4tlxvsg+DVviYeVT2rAjpCdlgMX0xhW6Apw02NRK/rB2eg/iW4NnwEOO0kAErfvYFSPWk9 734l0Za/d9cxaeQK2uT1eINH9rhHpbR9GKb152FQimp1T2wZb+GGvuUYykgCLszN3VtJW8Lzk4A5U I7HWRPBi6JP+TQUFwkIhfciFA57j87zbbzYyjAm85/XKFLKNDHEaIovIzqXa5vwraVeJilH+RIe5m eHQCATVnjsYDQz4I6tW/xtza4HMqyNN3M3/QWvIp7iiSqaDuctm2odTrkTJ0rdobU+uL9iBncrkK9 qn/+5T6Q==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vholQ-0000000DJVY-0Yog; Mon, 19 Jan 2026 12:53:48 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id A58743006CD; Mon, 19 Jan 2026 13:53:47 +0100 (CET) Date: Mon, 19 Jan 2026 13:53:47 +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 01/15] sched/idle: Handle offlining first in idle loop Message-ID: <20260119125347.GT830755@noisy.programming.kicks-ass.net> References: <20260116145208.87445-1-frederic@kernel.org> <20260116145208.87445-2-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260116145208.87445-2-frederic@kernel.org> On Fri, Jan 16, 2026 at 03:51:54PM +0100, Frederic Weisbecker wrote: > kernel/sched/idle.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index c174afe1dd17..35d79af3286d 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -260,6 +260,12 @@ static void do_idle(void) > { > int cpu = smp_processor_id(); > > + if (cpu_is_offline(cpu)) { Does it make sense to make that: if (unlikely(cpu_is_offline(cpu))) ? > + local_irq_disable(); Also, do we want something like: WARN_ON_ONCE(need_resched()); ? > + cpuhp_report_idle_dead(); > + arch_cpu_idle_dead(); > + } > + > /* > * Check if we need to update blocked load > */ > @@ -311,11 +317,6 @@ static void do_idle(void) > */ > local_irq_disable(); > > - if (cpu_is_offline(cpu)) { > - cpuhp_report_idle_dead(); > - arch_cpu_idle_dead(); > - } > - > arch_cpu_idle_enter(); > rcu_nocb_flush_deferred_wakeup(); > > -- > 2.51.1 >