From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp07.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 2E8EB2C0A84 for ; Sun, 23 Jun 2013 23:44:55 +1000 (EST) Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 23 Jun 2013 23:33:26 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id EC4052BB0044 for ; Sun, 23 Jun 2013 23:44:51 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5NDih7n54788202 for ; Sun, 23 Jun 2013 23:44:43 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5NDioht030067 for ; Sun, 23 Jun 2013 23:44:51 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH 16/45] tick-broadcast: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Date: Sun, 23 Jun 2013 19:11:31 +0530 Message-ID: <20130623134128.19094.36132.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> References: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: linux-arch@vger.kernel.org, nikunj@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, wangyun@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, netdev@vger.kernel.org, Thomas Gleixner , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Thomas Gleixner Signed-off-by: Srivatsa S. Bhat --- kernel/time/tick-broadcast.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index d66f554..53493a6 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -227,12 +227,14 @@ static void tick_do_broadcast(struct cpumask *mask) */ static void tick_do_periodic_broadcast(void) { + get_online_cpus_atomic(); raw_spin_lock(&tick_broadcast_lock); cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask); tick_do_broadcast(tmpmask); raw_spin_unlock(&tick_broadcast_lock); + put_online_cpus_atomic(); } /* @@ -335,11 +337,13 @@ out: */ void tick_broadcast_on_off(unsigned long reason, int *oncpu) { + get_online_cpus_atomic(); if (!cpumask_test_cpu(*oncpu, cpu_online_mask)) printk(KERN_ERR "tick-broadcast: ignoring broadcast for " "offline CPU #%d\n", *oncpu); else tick_do_broadcast_on_off(&reason); + put_online_cpus_atomic(); } /* @@ -505,6 +509,7 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) ktime_t now, next_event; int cpu, next_cpu = 0; + get_online_cpus_atomic(); raw_spin_lock(&tick_broadcast_lock); again: dev->next_event.tv64 = KTIME_MAX; @@ -562,6 +567,7 @@ again: goto again; } raw_spin_unlock(&tick_broadcast_lock); + put_online_cpus_atomic(); } /* @@ -753,6 +759,7 @@ void tick_broadcast_switch_to_oneshot(void) struct clock_event_device *bc; unsigned long flags; + get_online_cpus_atomic(); raw_spin_lock_irqsave(&tick_broadcast_lock, flags); tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; @@ -761,6 +768,7 @@ void tick_broadcast_switch_to_oneshot(void) tick_broadcast_setup_oneshot(bc); raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); + put_online_cpus_atomic(); }