From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932877AbdDRTxk (ORCPT ); Tue, 18 Apr 2017 15:53:40 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:53097 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932680AbdDRTuk (ORCPT ); Tue, 18 Apr 2017 15:50:40 -0400 Message-Id: <20170418170553.447314339@linutronix.de> User-Agent: quilt/0.63-1 Date: Tue, 18 Apr 2017 19:04:55 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Benjamin Herrenschmidt , Michael Ellerman , linuxppc-dev@lists.ozlabs.org Subject: [patch V2 13/24] powerpc/powernv: Use stop_machine_cpuslocked() References: <20170418170442.665445272@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=powerpcpowernv_Use_stop_machine_locked.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org set_subcores_per_core() holds get_online_cpus() while invoking stop_machine(). stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/platforms/powernv/subcore.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/powerpc/platforms/powernv/subcore.c +++ b/arch/powerpc/platforms/powernv/subcore.c @@ -356,7 +356,8 @@ static int set_subcores_per_core(int new /* Ensure state is consistent before we call the other cpus */ mb(); - stop_machine(cpu_update_split_mode, &new_mode, cpu_online_mask); + stop_machine_cpuslocked(cpu_update_split_mode, &new_mode, + cpu_online_mask); put_online_cpus(); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a01:7a0:2:106d:700::1]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3w6wjV0Xb9zDqC6 for ; Wed, 19 Apr 2017 05:50:54 +1000 (AEST) Message-Id: <20170418170553.447314339@linutronix.de> Date: Tue, 18 Apr 2017 19:04:55 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Benjamin Herrenschmidt , Michael Ellerman , linuxppc-dev@lists.ozlabs.org Subject: [patch V2 13/24] powerpc/powernv: Use stop_machine_cpuslocked() References: <20170418170442.665445272@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , set_subcores_per_core() holds get_online_cpus() while invoking stop_machine(). stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/platforms/powernv/subcore.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/powerpc/platforms/powernv/subcore.c +++ b/arch/powerpc/platforms/powernv/subcore.c @@ -356,7 +356,8 @@ static int set_subcores_per_core(int new /* Ensure state is consistent before we call the other cpus */ mb(); - stop_machine(cpu_update_split_mode, &new_mode, cpu_online_mask); + stop_machine_cpuslocked(cpu_update_split_mode, &new_mode, + cpu_online_mask); put_online_cpus();