From nobody Mon Feb 9 03:32:17 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 663EF332EA4 for ; Thu, 13 Nov 2025 08:33:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763022827; cv=none; b=JUacuSUIGV1sb82WfwaeCy/z0qHqrzqKopxS3PbNRkkAVQO3MdK/wLNFjEqb8QOp2XVgqepKVso/1k0DeGTR2TXqo+6AoUofOU22EfKj3hZDw0KIIWsDpcviZTd9KRZboAl1Z7MfIyET9AqmTUok5a7XIQSzu5CHe74+9A1FRY4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763022827; c=relaxed/simple; bh=O1KLHjYyILsWNv0K23ER9A6a+JvFFdfln/M3/tEcAfA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XQ0Gwjc2Nf5lxhvD9eu5EmSF7y2vfR6e4YVAQvcTqRj8Mc5zNW29S8i7fksIg0eowkheV1IU+q/ogulI3HPcLuepgTJH5mDkUL57DXHSBY+owD5TSOuyMd2Vmt/Ug5KFcyEpUgkSBIT0GlD5wDm+soH69Zd6Fn44Rh6S9IBynOY= 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=egswddKi; arc=none smtp.client-ip=170.10.133.124 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="egswddKi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763022824; 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=EXhcZhl0rUC9KYFyXlp7d+uvpM1hOj1o/nbf926Nj30=; b=egswddKiypYw4ZDq3pUHBNzIURTAPGT6v+v0OfqzHbeCEOGPye/Z9+NKrxeh312hhxQ+Kh SpsKWkHI8kiwT6ZnBhUjUYrudZANV3z/D1zcgF073CCPwnfZI7aNcyWakwVCGn9BX7pt63 shYvbA89tEJF5q5Aajfi9JMDIbf7HLA= 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-232-yH7VvIzhPB2Ny0d2-tj1qw-1; Thu, 13 Nov 2025 03:33:40 -0500 X-MC-Unique: yH7VvIzhPB2Ny0d2-tj1qw-1 X-Mimecast-MFC-AGG-ID: yH7VvIzhPB2Ny0d2-tj1qw_1763022819 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 CA46B180045C; Thu, 13 Nov 2025 08:33:39 +0000 (UTC) Received: from gmonaco-thinkpadt14gen3.rmtit.csb (unknown [10.44.32.78]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 10E511800451; Thu, 13 Nov 2025 08:33:36 +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 v15 2/7] timers: Add the available mask in timer migration Date: Thu, 13 Nov 2025 09:33:19 +0100 Message-ID: <20251113083324.33490-3-gmonaco@redhat.com> In-Reply-To: <20251113083324.33490-1-gmonaco@redhat.com> References: <20251113083324.33490-1-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 10.30.177.93 Content-Type: text/plain; charset="utf-8" Keep track of the CPUs available for timer migration in a cpumask. This prepares the ground to generalise the concept of unavailable CPUs. Reviewed-by: Frederic Weisbecker Signed-off-by: Gabriele Monaco Reviewed-by: Thomas Gleixner --- kernel/time/timer_migration.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c index d50514062a06..b8f07e4f59a6 100644 --- a/kernel/time/timer_migration.c +++ b/kernel/time/timer_migration.c @@ -424,6 +424,12 @@ static struct tmigr_group *tmigr_root; =20 static DEFINE_PER_CPU(struct tmigr_cpu, tmigr_cpu); =20 +/* + * CPUs available for timer migration. + * Protected by cpuset_mutex (with cpus_read_lock held) or cpus_write_lock. + */ +static cpumask_var_t tmigr_available_cpumask; + #define TMIGR_NONE 0xFF #define BIT_CNT 8 =20 @@ -1433,6 +1439,7 @@ static int tmigr_clear_cpu_available(unsigned int cpu) int migrator; u64 firstexp; =20 + cpumask_clear_cpu(cpu, tmigr_available_cpumask); raw_spin_lock_irq(&tmc->lock); tmc->available =3D false; WRITE_ONCE(tmc->wakeup, KTIME_MAX); @@ -1446,7 +1453,7 @@ static int tmigr_clear_cpu_available(unsigned int cpu) raw_spin_unlock_irq(&tmc->lock); =20 if (firstexp !=3D KTIME_MAX) { - migrator =3D cpumask_any_but(cpu_online_mask, cpu); + migrator =3D cpumask_any(tmigr_available_cpumask); work_on_cpu(migrator, tmigr_trigger_active, NULL); } =20 @@ -1461,6 +1468,7 @@ static int tmigr_set_cpu_available(unsigned int cpu) if (WARN_ON_ONCE(!tmc->tmgroup)) return -EINVAL; =20 + cpumask_set_cpu(cpu, tmigr_available_cpumask); raw_spin_lock_irq(&tmc->lock); trace_tmigr_cpu_available(tmc); tmc->idle =3D timer_base_is_idle(); @@ -1805,6 +1813,11 @@ static int __init tmigr_init(void) if (ncpus =3D=3D 1) return 0; =20 + if (!zalloc_cpumask_var(&tmigr_available_cpumask, GFP_KERNEL)) { + ret =3D -ENOMEM; + goto err; + } + /* * Calculate the required hierarchy levels. Unfortunately there is no * reliable information available, unless all possible CPUs have been --=20 2.51.1