From nobody Wed Oct 8 17:31:54 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 8A8AF11CBA for ; Thu, 26 Jun 2025 11:52:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750938731; cv=none; b=mCDeQsYcZZXcsHW68tZkT/+bofBDoIFs0un6W206tKVSh4/YxBEt+JCk45U7EZHzeikjys9dMQAu3fEZ2i9KAm2CP2BnCCBjyQ+mFozFkmom0aqiYlUQ/FgJzxxlzsHFi3XZlt5o8ZVtfezE46I84TQj7Yj1vfGof2okLEeKrx0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750938731; c=relaxed/simple; bh=Z2/gv7+X0ZzMXLFEamI/2p1sv1Pl42iZ+vozv6HjU24=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pbLZji+3a0NDOiAknvlKa0/H8KOOXr3T9D+SNgoJFIG/zUNGyFxyebUYxUy/LuvzFRtLv8iBeR2ll7nJZrXLuK8LsM+ltI7chtr8j6u1YVrClQTc1rTN29MZJDubrmVcijVIeWJXsuAoAPx1Mm4C6tE/02Iusxd03U7tR0VRq7U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=e48SAGMD; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="e48SAGMD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750938728; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HrL7UX5+CVWiMYZZfXK6ZU+JevGICkJqG7WxaABDFlA=; b=e48SAGMDdCO7Htyew/0AQK485IJs6uMCs62U79mG1qiMzL+oK9aUZtuakEXrkAJbSgPnW3 0HAOAddB4O4+7Y3lJ/1eGDw20QjVmmqB5/v8USDpDe5KvrdTNGL2ZdG9hHHduZfdYMGQUs LmIkwMW5zSDDfse1N+yp+ZH4kmyxGqw= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-661-3n6Az5-_O461PxD7QRGXbw-1; Thu, 26 Jun 2025 07:52:06 -0400 X-MC-Unique: 3n6Az5-_O461PxD7QRGXbw-1 X-Mimecast-MFC-AGG-ID: 3n6Az5-_O461PxD7QRGXbw_1750938725 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 601AC1809C96; Thu, 26 Jun 2025 11:52:05 +0000 (UTC) Received: from gmonaco-thinkpadt14gen3.rmtit.com (unknown [10.45.226.174]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id AE3A230002C5; Thu, 26 Jun 2025 11:52:02 +0000 (UTC) From: Gabriele Monaco To: linux-kernel@vger.kernel.org, Anna-Maria Behnsen , Frederic Weisbecker , Thomas Gleixner , Waiman Long Cc: Gabriele Monaco Subject: [PATCH v7 5/7] sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any Date: Thu, 26 Jun 2025 13:48:58 +0200 Message-ID: <20250626114900.106061-6-gmonaco@redhat.com> In-Reply-To: <20250626114900.106061-1-gmonaco@redhat.com> References: <20250626114900.106061-1-gmonaco@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" Currently the user can set up isolcpus and nohz_full in such a way that leaves no housekeeping CPU (i.e. no CPU that is neither domain isolated nor nohz full). This can be a problem for other subsystems (e.g. the timer wheel imgration). Prevent this configuration by invalidating the last setting in case the union of isolcpus and nohz_full covers all CPUs. Signed-off-by: Gabriele Monaco Reviewed-by: Frederic Weisbecker --- kernel/sched/isolation.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 93b038d48900a..0019d941de683 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -165,6 +165,18 @@ static int __init housekeeping_setup(char *str, unsign= ed long flags) } } =20 + /* Check in combination with the previously set cpumask */ + type =3D find_first_bit(&housekeeping.flags, HK_TYPE_MAX); + first_cpu =3D cpumask_first_and_and(cpu_present_mask, + housekeeping_staging, + housekeeping.cpumasks[type]); + if (first_cpu >=3D nr_cpu_ids || first_cpu >=3D setup_max_cpus) { + pr_warn("Housekeeping: must include one present CPU neither " + "in nohz_full=3D nor in isolcpus=3D, ignoring setting %s\n", + str); + goto free_housekeeping_staging; + } + iter_flags =3D flags & ~housekeeping.flags; =20 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) --=20 2.49.0