From nobody Tue Oct 7 07:01:24 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 C9318246BC7 for ; Mon, 14 Jul 2025 13:31:45 +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=1752499907; cv=none; b=EzNJxTBYZWPn2qyxST+5Ej1/xetgvJseQJXhQ7V4flmT11IWBx6GiHRmSXQr7LAmH1DQ4iK+WLUMNdf1Kl6AjRXqynSuWsSbjkTmzh5ab4f0qvyFtWzrAHmMLZWdYWeJx2tOKq83GcVMgaQbRi+G1atrnRXTAz7/2AonmT3CiEI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752499907; c=relaxed/simple; bh=/ngu1X8UAcAMW7nQ2qwEe/BTxf9ufDDdWdwrHIOq2LI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E0Sx1WhVDlwm1YJIwHNK5IPfZgwQiCAzHF2iVeb9g391qEqaLHeuvf4TAnwhEQ42PPI1RxsRg+3rJXmuVCWqKBKrhGmjM9YWsdYdoz9JEbYf9mH3H7JngYqVafvRHAN7pVDx5vFFcQiVOiFhwMKkCLDI4YKuFOWfXpqfRQjD0es= 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=KXVu7P1+; 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="KXVu7P1+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752499904; 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=zLism8EftLMfGY2XtmjU5c/SH0PZGP9bCy9WaqH4dis=; b=KXVu7P1+twDnWbbUjUv/Te1dmBmu2MD2x9QFu43eEbX0ExbpXjasFeuUCRTiOeSx5m+DP0 fDu5LWUpurfd2qZeUwMlztFXhBka+HtvxM6zoU3Uxq8usfxc+yl/8U4LwXsLaqA7j2t7gs z3GoR2dldmugmmVm0fjqwDaeRn8JQlU= 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-319-vd7WD3rdMsWLCrswPOQ82g-1; Mon, 14 Jul 2025 09:31:43 -0400 X-MC-Unique: vd7WD3rdMsWLCrswPOQ82g-1 X-Mimecast-MFC-AGG-ID: vd7WD3rdMsWLCrswPOQ82g_1752499902 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 1E0AF180A8FA; Mon, 14 Jul 2025 13:31:42 +0000 (UTC) Received: from gmonaco-thinkpadt14gen3.rmtit.com (unknown [10.45.225.215]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1FBDA19560A3; Mon, 14 Jul 2025 13:31:38 +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 v8 5/7] sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any Date: Mon, 14 Jul 2025 15:30:56 +0200 Message-ID: <20250714133050.193108-14-gmonaco@redhat.com> In-Reply-To: <20250714133050.193108-9-gmonaco@redhat.com> References: <20250714133050.193108-9-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 3.0 on 10.30.177.12 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. Reviewed-by: Frederic Weisbecker Signed-off-by: Gabriele Monaco --- 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 2.50.1