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 9EE934F85C0; Mon, 19 Oct 2026 13:10:05 +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=1792415406; cv=none; b=a4gFarMiXvZJ/yqR+N1Hj4WVcbgffkkKiSord3yBMLkkjz2w4QVEdG+2sciwyRpW4jzUPwvkvUl0l+zfhe+DKLp+2KQxFvMrZQf++H2Bh/LSMoPNbHll/PykvTYCukxydGlUVMJ1J/E/m92P4tNQoP5dSU4LdAR3yFtOTekUi2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792415406; c=relaxed/simple; bh=XOMLzrua8jW6fwKKzfLrHuCpk+XvYTexg4u3xo8uGb0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=McKX2fpi4kHiAdGH6AkQn/SbXEa0+d8sxdzSR9t72hnB46zF7He4Csaiwg/5z4HBPFvQcpgqZ4ELfYexWN3e0JqPbmS1q3ww3k+nNYiXLs7sG2/qE4AE8KVySJtQVM7KpRCRzubivMShCmO//OzE/8OO+hVypb/SrAYHyiZ5nH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oaj/uQ0x; 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="oaj/uQ0x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB22A1F000C4; Mon, 19 Oct 2026 13:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792415405; bh=5KUzkwxT6B3k7iZO7xyoYKNfooeaFIjmsalL+8Yuh5g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oaj/uQ0xpKpH+RbLxHdNBhU0cH4rJi/VrWI8reVtPQ1VmXDt57S4itU06PMtqTy33 ul08ke7/hVuzuRe7tWsdSBPIxOv1mGIQCg6ESobCEJ3w94Hv9FoxUyStbZe+tBqLIb NnLQqczJfhVQupMFx2i+0YGj+ON+cQ0hyQy7jGudFAMs3mgMFD/7zpQjG4PLV3y4QF gLpgaaQMMxbcgZZ5yt584n13abXYrWYtxQkB6dFjAK2KPxFUYd8QhnOYwuQbeLHlbn HcTLGCGayeRAqsO/Qd69JerrzwbcUSgFESjuqrAhnekFWFQ94/tqQFy9SevwDgByip EGrXfK//znusQ== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Albert Ou , Alexandre Ghiti , Anup Patel , Atish Patra , Marco Crivellari , Mark Rutland , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Phil Auld , Thomas Gleixner , Waiman Long , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [RFC PATCH 20/49] perf: RISC-V: Move CPUHP_AP_PERF_RISCV_STARTING post stop_machine() Date: Mon, 19 Oct 2026 15:08:27 +0200 Message-ID: <20261019130856.49711-21-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-perf-users@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: * Disables the per-cpu IRQ * Disables user-mode access to the CPU counter * Disables the shared memory snapshot of the CPU PMU. All these operations are local to the CPU and should be able to execute concurrently with other CPUs. 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 95cc6655cf7b..c69a265e4383 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_PERF_ARM_STARTING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_PERF_RISCV_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_PERF_ARM_STARTING); + WARN_ON(st->state != CPUHP_AP_PERF_RISCV_STARTING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0