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 9D30551120F for ; Mon, 19 Oct 2026 13:11:03 +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=1792415464; cv=none; b=QyYzggxJbV3DgHA+o82L37eNN5/UgYH+asl1c3MW2tp7cgo4jz6x+kj3ek14Yod9peWO/Il6wUdiIMzZeCE2NPu4ygqBahpRdHeoo/OPbcpqyFb6aZ7HKvNTPcZnmulHHL7IPVQggSuMsNZEeRi6Dq/rn9zCAnJm9oibuLXS3Ak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415464; c=relaxed/simple; bh=zuuRLtXQRnAriTMnXIszbBuRdBjwjS22i5X7gO80iN8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cWEuVoiD6K9KfiKVyb/JGAsPeFIF2D3b4Bl2oMM2brZGAS4lLNOe0hUukRkFJzDK7s18YiPJcNfZBHZA26aZ+dDg/BikaQe5bl4ykfhl0dzF1QiHzbupbspbDvo2IiG3Ty/QPHANd7LkDvJDD02IGy95McGFoVheZIq97cwhkSA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CzHYCm2V; 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="CzHYCm2V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC1B71F000C7; Mon, 19 Oct 2026 13:11:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792415463; bh=00ALhdrYDTfB9shpIDXwNm+/KmCDnWWqyzlUN/XfTUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CzHYCm2VzqU+45sKiQDVuaXpHXIKTVratlzfxIC2nKTsJcLBnOtKuPjXOTNimZtnF 2TQIqspQnqS58b0i/WggpdYFxjZwJWtQ0pb6xFZSlwfXciaj8Ms4e1PRe9e7uoDavF qAPALqPw9IVWDZAyPNEeyKyK03J1ckz/2wYusuXhjtLtaVMOHVqHzP0cmFpUsyIjaJ GP9eEm/RoEmH018WZOew1GOsfg3iCqu+4nXwKC62TnxNMOZxKbrZw9sqTOGg4FXlfp AtYjoIGSaEkTL+5fyhtWNgALD4deRDfach9Gg8YqxU1RKi1delS/80bVkfG4JA9Y+1 LzV88aTux+shA== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Marco Crivellari , Peter Zijlstra , Phil Auld , Thomas Gleixner , Waiman Long Subject: [RFC PATCH 43/49] smp: Move CPUHP_AP_SMPCFD_DYING post stop_machine() Date: Mon, 19 Oct 2026 15:08:50 +0200 Message-ID: <20261019130856.49711-44-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 outgoing CPU is observed as offline by other CPUs so no new IPI are supposed to be queued at this stage and the remaining callbacks can be executed while other CPUs are running, just like any online IPI handling. Move this teardown callback 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 c27e4aa109ba..4b3fcab1575c 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_ARM64_ISNDEP_STARTING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_SMPCFD_DYING); 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_ARM64_ISNDEP_STARTING); + WARN_ON(st->state != CPUHP_AP_SMPCFD_DYING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0