From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Rusty Russell <rusty@rustcorp.com.au>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Arjan van de Veen <arjan@infradead.org>,
Paul Turner <pjt@google.com>,
Richard Weinberger <rw@linutronix.de>,
Magnus Damm <magnus.damm@gmail.com>
Subject: Re: [patch 06/40] cpu: hotplug: Split out cpu down functions
Date: Fri, 8 Feb 2013 16:54:13 -0800 [thread overview]
Message-ID: <20130209005413.GA2666@linux.vnet.ibm.com> (raw)
In-Reply-To: <20130131120741.897171827@linutronix.de>
On Thu, Jan 31, 2013 at 12:11:16PM -0000, Thomas Gleixner wrote:
> Split cpu_down in separate functions in preparation for state machine
> conversion.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> kernel/cpu.c | 83 +++++++++++++++++++++++++++++++++++++----------------------
> 1 file changed, 53 insertions(+), 30 deletions(-)
>
> Index: linux-2.6/kernel/cpu.c
> ===================================================================
> --- linux-2.6.orig/kernel/cpu.c
> +++ linux-2.6/kernel/cpu.c
> @@ -206,11 +206,6 @@ static int bringup_cpu(unsigned int cpu)
> }
>
> #ifdef CONFIG_HOTPLUG_CPU
> -
> -static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
> -{
> - BUG_ON(cpu_notify(val, cpu));
> -}
> EXPORT_SYMBOL(register_cpu_notifier);
>
> void __ref unregister_cpu_notifier(struct notifier_block *nb)
> @@ -278,6 +273,25 @@ static inline void check_for_tasks(int c
> write_unlock_irq(&tasklist_lock);
> }
>
> +static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
> +{
> + BUG_ON(cpu_notify(val, cpu));
> +}
> +
> +static int notify_down_prepare(unsigned int cpu)
> +{
> + int err, nr_calls = 0;
> +
> + err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
> + if (err) {
> + nr_calls--;
> + __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
> + printk("%s: attempt to take down CPU %u failed\n",
> + __func__, cpu);
> + }
> + return err;
> +}
> +
> /* Take this CPU down. */
> static int __ref take_cpu_down(void *_param)
> {
> @@ -294,37 +308,17 @@ static int __ref take_cpu_down(void *_pa
> return 0;
> }
>
> -/* Requires cpu_add_remove_lock to be held */
> -static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
> +static int takedown_cpu(unsigned int cpu)
> {
> - int err, nr_calls = 0;
> -
> - if (num_online_cpus() == 1)
> - return -EBUSY;
> -
> - if (!cpu_online(cpu))
> - return -EINVAL;
> -
> - cpu_hotplug_begin();
> -
> - cpuhp_tasks_frozen = tasks_frozen;
> + int err;
>
> - err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
> - if (err) {
> - nr_calls--;
> - __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
> - printk("%s: attempt to take down CPU %u failed\n",
> - __func__, cpu);
> - goto out_release;
> - }
> smpboot_park_threads(cpu);
> -
> err = __stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
> if (err) {
> /* CPU didn't die: tell everyone. Can't complain. */
> smpboot_unpark_threads(cpu);
> cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
> - goto out_release;
> + return err;
> }
> BUG_ON(cpu_online(cpu));
>
> @@ -341,10 +335,39 @@ static int __ref _cpu_down(unsigned int
> /* This actually kills the CPU. */
> __cpu_die(cpu);
>
> - /* CPU is completely dead: tell everyone. Too late to complain. */
> - cpu_notify_nofail(CPU_DEAD, cpu);
> + return 0;
> +}
>
> +static int notify_dead(unsigned int cpu)
> +{
> + cpu_notify_nofail(CPU_DEAD, cpu);
> check_for_tasks(cpu);
> + return 0;
> +}
> +
> +/* Requires cpu_add_remove_lock to be held */
> +static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
> +{
> + int err;
> +
> + if (num_online_cpus() == 1)
> + return -EBUSY;
> +
> + if (!cpu_online(cpu))
> + return -EINVAL;
> +
> + cpu_hotplug_begin();
> +
> + cpuhp_tasks_frozen = tasks_frozen;
> +
> + err = notify_down_prepare(cpu);
> + if (err)
> + goto out_release;
> + err = takedown_cpu(cpu);
> + if (err)
> + goto out_release;
> +
> + notify_dead(cpu);
>
> out_release:
> cpu_hotplug_done();
>
>
next prev parent reply other threads:[~2013-02-09 0:58 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 15:44 [patch 00/40] CPU hotplug rework - episode I Thomas Gleixner
2013-01-31 12:11 ` [patch 01/40] smpboot: Allow selfparking per cpu threads Thomas Gleixner
2013-02-09 0:29 ` Paul E. McKenney
2013-02-14 17:46 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2013-01-31 12:11 ` [patch 02/40] stop_machine: Store task reference in a separate per cpu variable Thomas Gleixner
2013-02-09 0:33 ` Paul E. McKenney
2013-02-14 17:47 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2013-01-31 12:11 ` [patch 03/40] stop_machine: Use smpboot threads Thomas Gleixner
2013-02-09 0:39 ` Paul E. McKenney
2013-02-14 17:49 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2013-01-31 12:11 ` [patch 04/40] cpu: Restructure FROZEN state handling Thomas Gleixner
2013-02-09 0:52 ` Paul E. McKenney
2014-10-09 16:53 ` Borislav Petkov
2013-01-31 12:11 ` [patch 05/40] cpu: Restructure cpu_down code Thomas Gleixner
2013-02-09 0:49 ` Paul E. McKenney
2014-10-09 17:05 ` Borislav Petkov
2013-01-31 12:11 ` [patch 06/40] cpu: hotplug: Split out cpu down functions Thomas Gleixner
2013-02-09 0:54 ` Paul E. McKenney [this message]
2013-01-31 12:11 ` [patch 07/40] cpu: hotplug: Convert to a state machine for the control processor Thomas Gleixner
2013-02-11 20:09 ` Paul E. McKenney
2013-01-31 12:11 ` [patch 08/40] cpu: hotplug: Convert the hotplugged processor work to a state machine Thomas Gleixner
2013-02-11 20:17 ` Paul E. McKenney
2013-01-31 12:11 ` [patch 10/40] sched: Convert to state machine callbacks Thomas Gleixner
2013-02-11 23:46 ` Paul E. McKenney
2013-01-31 12:11 ` [patch 09/40] cpu: hotplug: Implement setup/removal interface Thomas Gleixner
2013-02-01 13:44 ` Hillf Danton
2013-02-01 13:52 ` Thomas Gleixner
2013-01-31 12:11 ` [patch 11/40] x86: uncore: Move teardown callback to CPU_DEAD Thomas Gleixner
2013-01-31 12:11 ` [patch 12/40] x86: uncore: Convert to hotplug state machine Thomas Gleixner
2013-01-31 12:11 ` [patch 13/40] perf: " Thomas Gleixner
2013-01-31 12:11 ` [patch 14/40] x86: perf: Convert the core to the " Thomas Gleixner
2013-01-31 12:11 ` [patch 16/40] blackfin: perf: Convert hotplug notifier to " Thomas Gleixner
2013-01-31 12:11 ` [patch 15/40] x86: perf: Convert AMD IBS to hotplug " Thomas Gleixner
2013-01-31 12:11 ` [patch 17/40] powerpc: perf: Convert book3s notifier to state machine callbacks Thomas Gleixner
2013-01-31 12:11 ` [patch 18/40] s390: perf: Convert the hotplug " Thomas Gleixner
2013-01-31 12:11 ` [patch 19/40] sh: perf: Convert the hotplug notifiers " Thomas Gleixner
2013-01-31 12:11 ` [patch 21/40] sched: Convert the migration callback to hotplug states Thomas Gleixner
2013-01-31 12:11 ` [patch 20/40] perf: Remove perf cpu notifier code Thomas Gleixner
2013-01-31 12:11 ` [patch 22/40] workqueue: Convert to state machine callbacks Thomas Gleixner
2013-01-31 12:11 ` [patch 23/40] cpufreq: Convert to hotplug state machine Thomas Gleixner
2013-01-31 12:11 ` [patch 24/40] arm64: Convert generic timers " Thomas Gleixner
2013-01-31 12:11 ` [patch 25/40] arm: Convert VFP hotplug notifiers to " Thomas Gleixner
2013-01-31 12:11 ` [patch 26/40] arm: perf: Convert to hotplug " Thomas Gleixner
2013-01-31 12:11 ` [patch 27/40] virt: Convert kvm hotplug to " Thomas Gleixner
2013-01-31 12:11 ` [patch 28/40] cpuhotplug: Remove CPU_STARTING notifier Thomas Gleixner
2013-01-31 12:11 ` [patch 29/40] s390: Convert vtime to hotplug state machine Thomas Gleixner
2013-01-31 12:11 ` [patch 30/40] x86: tboot: Convert " Thomas Gleixner
2013-01-31 12:11 ` [patch 31/40] sched: Convert fair nohz balancer " Thomas Gleixner
2013-01-31 12:11 ` [patch 33/40] hrtimer: Convert " Thomas Gleixner
2013-01-31 12:11 ` [patch 32/40] rcu: Convert rcutree " Thomas Gleixner
2013-02-12 0:01 ` Paul E. McKenney
2013-02-12 15:50 ` Paul E. McKenney
2013-01-31 12:11 ` [patch 34/40] cpuhotplug: Remove CPU_DYING notifier Thomas Gleixner
2013-01-31 12:11 ` [patch 35/40] timers: Convert to hotplug state machine Thomas Gleixner
2013-01-31 12:11 ` [patch 36/40] profile: Convert ot " Thomas Gleixner
2013-01-31 12:11 ` [patch 37/40] x86: x2apic: Convert to cpu " Thomas Gleixner
2013-01-31 12:11 ` [patch 38/40] smp: Convert core to " Thomas Gleixner
2013-01-31 12:11 ` [patch 39/40] relayfs: Convert " Thomas Gleixner
2013-01-31 12:11 ` [patch 40/40] slab: " Thomas Gleixner
2013-01-31 20:23 ` [patch 00/40] CPU hotplug rework - episode I Andrew Morton
2013-01-31 21:48 ` Thomas Gleixner
2013-01-31 21:59 ` Linus Torvalds
2013-01-31 22:44 ` Thomas Gleixner
2013-01-31 22:55 ` Linus Torvalds
2013-02-01 10:51 ` Thomas Gleixner
2013-02-07 4:01 ` Rusty Russell
2013-02-09 0:28 ` Paul E. McKenney
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