From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DE5D82ECD2A; Mon, 19 Jan 2026 21:04:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768856692; cv=none; b=e9eZbrW+5ImMvLfoBe0LAuR7iEnuC9s2EG6oLmLG9OiGQP5METNuwOR9+aSZabrlpE2RZlifmC7GHhKphbcE2VNDQR/95mgDDkI5lVgn03rQ044QcrI2ASYoh7PBs0s2xNPG4WEr2H3a0vctkIIFwb71tcxB4jRqmXXBUR6OwiQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768856692; c=relaxed/simple; bh=6o+770Yuc3JjhJgvTCTVGSnWnwzkyqp25xUHsXx/C6U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FeByR0d1kd6xt+S3OTCtqZb3i3HGY82+hGBzWKKJd+y1FlFCnp+RUDykTH2DzuqBnirWCZlZA3FT26zxvrkRAPOMor2Bmo7H9MmZq1cuuTq5oZrk5aWboPOYknDguY0NcthzKpC4mqqnSRUKinoyn/E5mY48orqRz0ah3cV1hbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iXD2y8uy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iXD2y8uy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7ABEC116C6; Mon, 19 Jan 2026 21:04:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768856692; bh=6o+770Yuc3JjhJgvTCTVGSnWnwzkyqp25xUHsXx/C6U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iXD2y8uyJXn1wpB61gKSaO/rK1kVC3HviBmxyTELifn8la3q38wzR/8/FAe+5fNYl ik+9L6OTEhlmGu1UQdY4aD1a5aW7HYIXswoYSgJh7xMmBDk3dBcl2jDRPQ3Gekd589 SW9zUCR9XPe6pZCj0TKHTnObA3HPP0+tHT8d3okl57iIQ4vOrOe60WdPZmfCCXT5Sc 6Z8dPnAGg1Dv34Rm1pypG+/y+3MHgCNUROe90BwGxYzcjF9MSHa3jR/Mg0xsSEaBI0 mYwEoCld9S81GOQ2xQZh3gPzMLIX2nazcrTF/Va1DfE4XpjmaE6W4b3KxEe9XYL5Ud PiMpAlO96fSFA== Date: Mon, 19 Jan 2026 22:04:49 +0100 From: Frederic Weisbecker To: Peter Zijlstra 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: References: <20260116145208.87445-1-frederic@kernel.org> <20260116145208.87445-2-frederic@kernel.org> <20260119125347.GT830755@noisy.programming.kicks-ass.net> 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260119125347.GT830755@noisy.programming.kicks-ass.net> Le Mon, Jan 19, 2026 at 01:53:47PM +0100, Peter Zijlstra a écrit : > 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))) ? Yes indeed! > > > + local_irq_disable(); > > Also, do we want something like: > > WARN_ON_ONCE(need_resched()); > > ? Definetly. Thanks. -- Frederic Weisbecker SUSE Labs