From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E617FCCF2E3 for ; Mon, 19 Oct 2026 13:10:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=agCw1h+tg2HhF7GH4iWgeqQSvS4+wCtaUhhRsD0uEvQ=; b=rIKHqNxax+Xup9UtKz40LizBvC L4STTCwIQkGlIvxNbxUChksDUSex2qEPP60ukprxNijFZoYYqgkW7OSfLDD5DiZdlpnJC4uKL8dw0 FSdmZf4YAMcc5EvM51e/Jxqo0ltkZTSqfjx9DHvc/z7wX322p+e9ZAO4t4Xa1vVW472xRSrbflkXL yU5EBCl4tYyHW50WV5wGaltwnoLAPX0bKNOhAcyZmoRGMDoe+RvwTdFpSUceShWml/i+1mGUnjdKr i1phMM4sufaR2SQhOg3XYccy2jBCr0s4I4KTdtM1sb9gJxOIv4ERgITp4+RP2camyRzvsvDlLXHB7 oP+Wh2kA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xIn89-00000007TLp-2h2H; Mon, 19 Oct 2026 13:10:21 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xIn84-00000007THd-3n7O for linux-arm-kernel@lists.infradead.org; Mon, 19 Oct 2026 13:10:16 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 5788F6025F; Mon, 19 Oct 2026 13:10:16 +0000 (UTC) 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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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