On 3/1/16 2:51 PM, tip-bot for Thomas Gleixner wrote: > Commit-ID: 090e77c391dd983c8945b8e2e16d09f378d2e334 > Gitweb: http://git.kernel.org/tip/090e77c391dd983c8945b8e2e16d09f378d2e334 > Author: Thomas Gleixner <[email protected]> > AuthorDate: Fri, 26 Feb 2016 18:43:23 +0000 > Committer: Thomas Gleixner <[email protected]> > CommitDate: Tue, 1 Mar 2016 20:36:53 +0100 > > cpu/hotplug: Restructure FROZEN state handling > > There are only a few callbacks which really care about FROZEN > vs. !FROZEN. No need to have extra states for this. > > Publish the frozen state in an extra variable which is updated under > the hotplug lock and let the users interested deal with it w/o > imposing that extra state checks on everyone. > > Signed-off-by: Thomas Gleixner <[email protected]> > Cc: [email protected] > Cc: Rik van Riel <[email protected]> > Cc: Rafael Wysocki <[email protected]> > Cc: "Srivatsa S. Bhat" <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Arjan van de Ven <[email protected]> > Cc: Sebastian Siewior <[email protected]> > Cc: Rusty Russell <[email protected]> > Cc: Steven Rostedt <[email protected]> > Cc: Oleg Nesterov <[email protected]> > Cc: Tejun Heo <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Paul McKenney <[email protected]> > Cc: Linus Torvalds <[email protected]> > Cc: Paul Turner <[email protected]> > Link: http://lkml.kernel.org/r/[email protected] > Signed-off-by: Thomas Gleixner <[email protected]> > ---
Reviewed-by: Srivatsa S. Bhat <[email protected]> Regards, Srivatsa S. Bhat > include/linux/cpu.h | 2 ++ > kernel/cpu.c | 69 > ++++++++++++++++++++++------------------------------- > 2 files changed, 31 insertions(+), 40 deletions(-) > > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index d2ca8c3..f2fb549 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -118,6 +118,7 @@ enum { > > > #ifdef CONFIG_SMP > +extern bool cpuhp_tasks_frozen; > /* Need to know about CPUs going up/down? */ > #if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE) > #define cpu_notifier(fn, pri) { \ > @@ -177,6 +178,7 @@ extern void cpu_maps_update_done(void); > #define cpu_notifier_register_done cpu_maps_update_done > > #else /* CONFIG_SMP */ > +#define cpuhp_tasks_frozen 0 > > #define cpu_notifier(fn, pri) do { (void)(fn); } while (0) > #define __cpu_notifier(fn, pri) do { (void)(fn); } while (0) > diff --git a/kernel/cpu.c b/kernel/cpu.c > index 5b9d396..41a6cb8 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -29,6 +29,8 @@ > #ifdef CONFIG_SMP > /* Serializes the updates to cpu_online_mask, cpu_present_mask */ > static DEFINE_MUTEX(cpu_add_remove_lock); > +bool cpuhp_tasks_frozen; > +EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); > > /* > * The following two APIs (cpu_maps_update_begin/done) must be used when > @@ -207,27 +209,30 @@ int __register_cpu_notifier(struct notifier_block *nb) > return raw_notifier_chain_register(&cpu_chain, nb); > } > > -static int __cpu_notify(unsigned long val, void *v, int nr_to_call, > +static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call, > int *nr_calls) > { > + unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; > + void *hcpu = (void *)(long)cpu; > + > int ret; > > - ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, > + ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call, > nr_calls); > > return notifier_to_errno(ret); > } > > -static int cpu_notify(unsigned long val, void *v) > +static int cpu_notify(unsigned long val, unsigned int cpu) > { > - return __cpu_notify(val, v, -1, NULL); > + return __cpu_notify(val, cpu, -1, NULL); > } > > #ifdef CONFIG_HOTPLUG_CPU > > -static void cpu_notify_nofail(unsigned long val, void *v) > +static void cpu_notify_nofail(unsigned long val, unsigned int cpu) > { > - BUG_ON(cpu_notify(val, v)); > + BUG_ON(cpu_notify(val, cpu)); > } > EXPORT_SYMBOL(register_cpu_notifier); > EXPORT_SYMBOL(__register_cpu_notifier); > @@ -311,27 +316,21 @@ static inline void check_for_tasks(int dead_cpu) > read_unlock(&tasklist_lock); > } > > -struct take_cpu_down_param { > - unsigned long mod; > - void *hcpu; > -}; > - > /* Take this CPU down. */ > static int take_cpu_down(void *_param) > { > - struct take_cpu_down_param *param = _param; > - int err; > + int err, cpu = smp_processor_id(); > > /* Ensure this CPU doesn't handle any more interrupts. */ > err = __cpu_disable(); > if (err < 0) > return err; > > - cpu_notify(CPU_DYING | param->mod, param->hcpu); > + cpu_notify(CPU_DYING, cpu); > /* Give up timekeeping duties */ > tick_handover_do_timer(); > /* Park the stopper thread */ > - stop_machine_park((long)param->hcpu); > + stop_machine_park(cpu); > return 0; > } > > @@ -339,12 +338,6 @@ static int take_cpu_down(void *_param) > static int _cpu_down(unsigned int cpu, int tasks_frozen) > { > int err, nr_calls = 0; > - void *hcpu = (void *)(long)cpu; > - unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; > - struct take_cpu_down_param tcd_param = { > - .mod = mod, > - .hcpu = hcpu, > - }; > > if (num_online_cpus() == 1) > return -EBUSY; > @@ -354,10 +347,12 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) > > cpu_hotplug_begin(); > > - err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); > + cpuhp_tasks_frozen = tasks_frozen; > + > + err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); > if (err) { > nr_calls--; > - __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); > + __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); > pr_warn("%s: attempt to take down CPU %u failed\n", > __func__, cpu); > goto out_release; > @@ -389,10 +384,10 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) > /* > * So now all preempt/rcu users must observe !cpu_active(). > */ > - err = stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); > + err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); > if (err) { > /* CPU didn't die: tell everyone. Can't complain. */ > - cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); > + cpu_notify_nofail(CPU_DOWN_FAILED, cpu); > irq_unlock_sparse(); > goto out_release; > } > @@ -419,14 +414,14 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) > > /* CPU is completely dead: tell everyone. Too late to complain. */ > tick_cleanup_dead_cpu(cpu); > - cpu_notify_nofail(CPU_DEAD | mod, hcpu); > + cpu_notify_nofail(CPU_DEAD, cpu); > > check_for_tasks(cpu); > > out_release: > cpu_hotplug_done(); > if (!err) > - cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); > + cpu_notify_nofail(CPU_POST_DEAD, cpu); > return err; > } > > @@ -485,10 +480,8 @@ void smpboot_thread_init(void) > /* Requires cpu_add_remove_lock to be held */ > static int _cpu_up(unsigned int cpu, int tasks_frozen) > { > - int ret, nr_calls = 0; > - void *hcpu = (void *)(long)cpu; > - unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; > struct task_struct *idle; > + int ret, nr_calls = 0; > > cpu_hotplug_begin(); > > @@ -507,7 +500,9 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen) > if (ret) > goto out; > > - ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); > + cpuhp_tasks_frozen = tasks_frozen; > + > + ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); > if (ret) { > nr_calls--; > pr_warn("%s: attempt to bring up CPU %u failed\n", > @@ -523,11 +518,11 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen) > BUG_ON(!cpu_online(cpu)); > > /* Now call notifier in preparation. */ > - cpu_notify(CPU_ONLINE | mod, hcpu); > + cpu_notify(CPU_ONLINE, cpu); > > out_notify: > if (ret != 0) > - __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); > + __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); > out: > cpu_hotplug_done(); > > @@ -719,13 +714,7 @@ core_initcall(cpu_hotplug_pm_sync_init); > */ > void notify_cpu_starting(unsigned int cpu) > { > - unsigned long val = CPU_STARTING; > - > -#ifdef CONFIG_PM_SLEEP_SMP > - if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) > - val = CPU_STARTING_FROZEN; > -#endif /* CONFIG_PM_SLEEP_SMP */ > - cpu_notify(val, (void *)(long)cpu); > + cpu_notify(CPU_STARTING, cpu); > } > > #endif /* CONFIG_SMP */ >
