From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 277D94FD7A3 for ; Mon, 19 Oct 2026 13:10:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415417; cv=none; b=YOElzB6lbvn3YVEBQFzqB+6x565aB1OjjKNfmBC+17l6KPbvWO5yENi0sth/L1hYuURO8fOB7viX+yd2+vAY1taeKCXcX7xv01qkcpw7XGAeoKm0DSqf5+wDgx6yTGijM6UrsRRdbWZSUxSb/0JBqFKvtFRyeKIYPcrWR90XQrc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415417; c=relaxed/simple; bh=Wm+rxjE7YHmz8PJBdzJM/PH/ADkxTKLbwB04Km9zwgA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rcE3X7jqpsZtesi6gw2wuTG3ofPkfKU4AZZkfv0nRNUgHJlZxMfY7kOP0tkECnpM7bFEWrk6qLt6DxNwz+9bjqevJk/Hjbens3NMjWwboMKkUbkDK6P9SQ/owUSSkzVV2qzlWJ7UckWVyJwlvmmeHatVJLQTYjK4jIUZekdJ2Mc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nujvMSPs; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nujvMSPs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBEA41F000C5; Mon, 19 Oct 2026 13:10:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792415416; bh=agCw1h+tg2HhF7GH4iWgeqQSvS4+wCtaUhhRsD0uEvQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=nujvMSPsk5RqsOR8xFIrjNXzPdVIxmPTsHdrILSym+8vouuexZcD3X6nFqHaY7sI1 LnSkTT5Zivnr1beBZLAwJMM+W/uCePLTKbl5s/B97ug4HssaGcC1L9SejTYajKTgBj H8s+Gx2wnom28qvNlw7WEUXBLlQ6bo9VLIavpCJyLG1WJmwA0Fxu3/rxZSFu1HQRmW udV66VpWM4oHJYtgmeCdFF5mPATiavo/XBhZxE/BFaotKw0WHHxMezTGQcv9FxSV2e eSunQHttnzoMHU2aZPNuAM4FzkO6jtRHbnY2LdN9GXq4XyVne/588235beKHCLtWdd +5euW+iEovI7A== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Daniel Lezcano , Marc Zyngier , Marco Crivellari , Mark Rutland , Peter Zijlstra , Phil Auld , Thomas Gleixner , Waiman Long , linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH 24/49] clocksource/drivers/arm_arch_timer: Move CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING post stop_machine() Date: Mon, 19 Oct 2026 15:08:31 +0200 Message-ID: <20261019130856.49711-25-frederic@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261019130856.49711-1-frederic@kernel.org> References: <20261019130856.49711-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Between CPUHP_TEARDOWN_CPU and CPUHP_AP_OFFLINE, stop_machine executes all the teardown callbacks while stopping all CPUs in the system. This doesn't mix-up well with running RT or isolated tasks. In order to transition smoothly from global stop_machine to finer grained synchronization between teardown callbacks and the other CPUs, a new stop machine post function has been introduced to be executed after the main one with IRQs still disabled while other CPUs can exit stop_machine(). The teardown callback here only clears the CPU from the evtstrm_available cpumask, which is only ever checked locally for the current CPU. And set/clear from other CPUs are atomic. Therefore this callback is safe to run concurrently with other CPUs. Move it to post stop_machine() accordingly. Signed-off-by: Frederic Weisbecker --- kernel/cpu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 90d37ee0f282..ca335111abb2 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1275,7 +1275,7 @@ void clear_tasks_mm_cpumask(int cpu) static int take_cpu_down(void *_param) { struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); - enum cpuhp_state target = max((int)st->target, CPUHP_AP_ARM_ARCH_TIMER_STARTING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING); int err, cpu = smp_processor_id(); /* Ensure this CPU doesn't handle any more interrupts. */ @@ -1303,7 +1303,7 @@ static int take_cpu_down_post(void *_param) enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); int cpu = smp_processor_id(); - WARN_ON(st->state != CPUHP_AP_ARM_ARCH_TIMER_STARTING); + WARN_ON(st->state != CPUHP_AP_ARM_ARCH_TIMER_EVTSTRM_STARTING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0