From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sebastian Siewior <bigeasy@linutronix.de>
Subject: Re: [patch V3 01/32] cpu/hotplug: Provide cpus_read|write_[un]lock()
Date: Wed, 24 May 2017 09:25:38 -0700 [thread overview]
Message-ID: <20170524162538.GE3956@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170524081547.080397752@linutronix.de>
On Wed, May 24, 2017 at 10:15:12AM +0200, Thomas Gleixner wrote:
> The counting 'rwsem' hackery of get|put_online_cpus() is going to be
> replaced by percpu rwsem.
>
> Rename the functions to make it clear that it's locking and not some
> refcount style interface. These new functions will be used for the
> preparatory patches which make the code ready for the percpu rwsem
> conversion.
>
> Rename all instances in the cpu hotplug code while at it.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> include/linux/cpu.h | 32 ++++++++++++++++++--------------
> kernel/cpu.c | 36 ++++++++++++++++++------------------
> 2 files changed, 36 insertions(+), 32 deletions(-)
>
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -99,26 +99,30 @@ static inline void cpu_maps_update_done(
> extern struct bus_type cpu_subsys;
>
> #ifdef CONFIG_HOTPLUG_CPU
> -/* Stop CPUs going up and down. */
> -
> -extern void cpu_hotplug_begin(void);
> -extern void cpu_hotplug_done(void);
> -extern void get_online_cpus(void);
> -extern void put_online_cpus(void);
> +extern void cpus_write_lock(void);
> +extern void cpus_write_unlock(void);
> +extern void cpus_read_lock(void);
> +extern void cpus_read_unlock(void);
> extern void cpu_hotplug_disable(void);
> extern void cpu_hotplug_enable(void);
> void clear_tasks_mm_cpumask(int cpu);
> int cpu_down(unsigned int cpu);
>
> -#else /* CONFIG_HOTPLUG_CPU */
> +#else /* CONFIG_HOTPLUG_CPU */
> +
> +static inline void cpus_write_lock(void) { }
> +static inline void cpus_write_unlock(void) { }
> +static inline void cpus_read_lock(void) { }
> +static inline void cpus_read_unlock(void) { }
> +static inline void cpu_hotplug_disable(void) { }
> +static inline void cpu_hotplug_enable(void) { }
> +#endif /* !CONFIG_HOTPLUG_CPU */
>
> -static inline void cpu_hotplug_begin(void) {}
> -static inline void cpu_hotplug_done(void) {}
> -#define get_online_cpus() do { } while (0)
> -#define put_online_cpus() do { } while (0)
> -#define cpu_hotplug_disable() do { } while (0)
> -#define cpu_hotplug_enable() do { } while (0)
> -#endif /* CONFIG_HOTPLUG_CPU */
> +/* Wrappers which go away once all code is converted */
> +static inline void cpu_hotplug_begin(void) { cpus_write_lock(); }
> +static inline void cpu_hotplug_done(void) { cpus_write_unlock(); }
> +static inline void get_online_cpus(void) { cpus_read_lock(); }
> +static inline void put_online_cpus(void) { cpus_read_unlock(); }
>
> #ifdef CONFIG_PM_SLEEP_SMP
> extern int freeze_secondary_cpus(int primary);
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -235,7 +235,7 @@ static struct {
> #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
>
>
> -void get_online_cpus(void)
> +void cpus_read_lock(void)
> {
> might_sleep();
> if (cpu_hotplug.active_writer == current)
> @@ -245,9 +245,9 @@ void get_online_cpus(void)
> atomic_inc(&cpu_hotplug.refcount);
> mutex_unlock(&cpu_hotplug.lock);
> }
> -EXPORT_SYMBOL_GPL(get_online_cpus);
> +EXPORT_SYMBOL_GPL(cpus_read_lock);
>
> -void put_online_cpus(void)
> +void cpus_read_unlock(void)
> {
> int refcount;
>
> @@ -264,7 +264,7 @@ void put_online_cpus(void)
> cpuhp_lock_release();
>
> }
> -EXPORT_SYMBOL_GPL(put_online_cpus);
> +EXPORT_SYMBOL_GPL(cpus_read_unlock);
>
> /*
> * This ensures that the hotplug operation can begin only when the
> @@ -288,7 +288,7 @@ EXPORT_SYMBOL_GPL(put_online_cpus);
> * get_online_cpus() not an api which is called all that often.
> *
> */
> -void cpu_hotplug_begin(void)
> +void cpus_write_lock(void)
> {
> DEFINE_WAIT(wait);
>
> @@ -306,7 +306,7 @@ void cpu_hotplug_begin(void)
> finish_wait(&cpu_hotplug.wq, &wait);
> }
>
> -void cpu_hotplug_done(void)
> +void cpus_write_unlock(void)
> {
> cpu_hotplug.active_writer = NULL;
> mutex_unlock(&cpu_hotplug.lock);
> @@ -773,7 +773,7 @@ static int __ref _cpu_down(unsigned int
> if (!cpu_present(cpu))
> return -EINVAL;
>
> - cpu_hotplug_begin();
> + cpus_write_lock();
>
> cpuhp_tasks_frozen = tasks_frozen;
>
> @@ -811,7 +811,7 @@ static int __ref _cpu_down(unsigned int
> }
>
> out:
> - cpu_hotplug_done();
> + cpus_write_unlock();
> return ret;
> }
>
> @@ -893,7 +893,7 @@ static int _cpu_up(unsigned int cpu, int
> struct task_struct *idle;
> int ret = 0;
>
> - cpu_hotplug_begin();
> + cpus_write_lock();
>
> if (!cpu_present(cpu)) {
> ret = -EINVAL;
> @@ -941,7 +941,7 @@ static int _cpu_up(unsigned int cpu, int
> target = min((int)target, CPUHP_BRINGUP_CPU);
> ret = cpuhp_up_callbacks(cpu, st, target);
> out:
> - cpu_hotplug_done();
> + cpus_write_unlock();
> return ret;
> }
>
> @@ -1424,7 +1424,7 @@ int __cpuhp_state_add_instance(enum cpuh
> if (sp->multi_instance == false)
> return -EINVAL;
>
> - get_online_cpus();
> + cpus_read_lock();
> mutex_lock(&cpuhp_state_mutex);
>
> if (!invoke || !sp->startup.multi)
> @@ -1453,7 +1453,7 @@ int __cpuhp_state_add_instance(enum cpuh
> hlist_add_head(node, &sp->list);
> unlock:
> mutex_unlock(&cpuhp_state_mutex);
> - put_online_cpus();
> + cpus_read_unlock();
> return ret;
> }
> EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
> @@ -1486,7 +1486,7 @@ int __cpuhp_setup_state(enum cpuhp_state
> if (cpuhp_cb_check(state) || !name)
> return -EINVAL;
>
> - get_online_cpus();
> + cpus_read_lock();
> mutex_lock(&cpuhp_state_mutex);
>
> ret = cpuhp_store_callbacks(state, name, startup, teardown,
> @@ -1522,7 +1522,7 @@ int __cpuhp_setup_state(enum cpuhp_state
> }
> out:
> mutex_unlock(&cpuhp_state_mutex);
> - put_online_cpus();
> + cpus_read_unlock();
> /*
> * If the requested state is CPUHP_AP_ONLINE_DYN, return the
> * dynamically allocated state in case of success.
> @@ -1544,7 +1544,7 @@ int __cpuhp_state_remove_instance(enum c
> if (!sp->multi_instance)
> return -EINVAL;
>
> - get_online_cpus();
> + cpus_read_lock();
> mutex_lock(&cpuhp_state_mutex);
>
> if (!invoke || !cpuhp_get_teardown_cb(state))
> @@ -1565,7 +1565,7 @@ int __cpuhp_state_remove_instance(enum c
> remove:
> hlist_del(node);
> mutex_unlock(&cpuhp_state_mutex);
> - put_online_cpus();
> + cpus_read_unlock();
>
> return 0;
> }
> @@ -1587,7 +1587,7 @@ void __cpuhp_remove_state(enum cpuhp_sta
>
> BUG_ON(cpuhp_cb_check(state));
>
> - get_online_cpus();
> + cpus_read_lock();
>
> mutex_lock(&cpuhp_state_mutex);
> if (sp->multi_instance) {
> @@ -1615,7 +1615,7 @@ void __cpuhp_remove_state(enum cpuhp_sta
> remove:
> cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
> mutex_unlock(&cpuhp_state_mutex);
> - put_online_cpus();
> + cpus_read_unlock();
> }
> EXPORT_SYMBOL(__cpuhp_remove_state);
>
>
>
next prev parent reply other threads:[~2017-05-24 16:25 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-24 8:15 [patch V3 00/32] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Thomas Gleixner
2017-05-24 8:15 ` [patch V3 01/32] cpu/hotplug: Provide cpus_read|write_[un]lock() Thomas Gleixner
2017-05-24 16:25 ` Paul E. McKenney [this message]
2017-05-26 8:31 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 02/32] cpu/hotplug: Provide lockdep_assert_cpus_held() Thomas Gleixner
2017-05-24 16:26 ` Paul E. McKenney
2017-05-26 8:32 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 03/32] cpu/hotplug: Provide cpuhp_setup/remove_state[_nocalls]_cpuslocked() Thomas Gleixner
2017-05-26 8:32 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 04/32] cpu/hotplug: Add __cpuhp_state_add_instance_cpuslocked() Thomas Gleixner
2017-05-26 8:33 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 05/32] stop_machine: Provide stop_machine_cpuslocked() Thomas Gleixner
2017-05-24 17:42 ` Paul E. McKenney
2017-05-26 8:33 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 06/32] padata: Make padata_alloc() static Thomas Gleixner
2017-05-26 8:34 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 07/32] padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata() Thomas Gleixner
2017-05-26 8:35 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 08/32] x86/mtrr: Remove get_online_cpus() from mtrr_save_state() Thomas Gleixner
2017-05-26 8:35 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 09/32] cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked() Thomas Gleixner
2017-05-26 8:36 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 10/32] KVM/PPC/Book3S HV: " Thomas Gleixner
2017-05-26 8:36 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 11/32] hwtracing/coresight-etm3x: " Thomas Gleixner
2017-05-25 16:46 ` Mathieu Poirier
2017-05-26 8:37 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 12/32] hwtracing/coresight-etm4x: " Thomas Gleixner
2017-05-25 16:47 ` Mathieu Poirier
2017-05-26 8:37 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 13/32] perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked() Thomas Gleixner
2017-05-26 8:38 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 14/32] ARM/hw_breakpoint: " Thomas Gleixner
2017-05-26 8:38 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 15/32] s390/kernel: Use stop_machine_cpuslocked() Thomas Gleixner
2017-05-24 10:57 ` Heiko Carstens
2017-05-26 8:39 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 16/32] powerpc/powernv: " Thomas Gleixner
2017-05-26 8:40 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 17/32] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() Thomas Gleixner
2017-05-26 8:40 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 18/32] x86/perf: Drop EXPORT of perf_check_microcode Thomas Gleixner
2017-05-26 8:41 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 19/32] perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() Thomas Gleixner
2017-05-26 8:41 ` [tip:smp/hotplug] " tip-bot for Sebastian Andrzej Siewior
2017-05-24 8:15 ` [patch V3 20/32] PCI: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-05-26 8:42 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 21/32] PCI: Replace the racy recursion prevention Thomas Gleixner
2017-05-26 8:42 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 22/32] ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-05-26 8:43 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 23/32] perf/tracing/cpuhotplug: Fix locking order Thomas Gleixner
2017-05-24 18:30 ` Paul E. McKenney
2017-05-24 18:47 ` Thomas Gleixner
2017-05-24 21:10 ` Paul E. McKenney
2017-05-30 11:22 ` Peter Zijlstra
2017-05-30 16:25 ` Paul E. McKenney
2017-05-26 8:43 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 24/32] jump_label: Reorder hotplug lock and jump_label_lock Thomas Gleixner
2017-05-24 12:50 ` David Miller
2017-05-26 8:44 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 25/32] kprobes: Cure hotplug lock ordering issues Thomas Gleixner
2017-05-24 15:54 ` Masami Hiramatsu
2017-05-26 7:47 ` Thomas Gleixner
2017-05-26 8:45 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 26/32] arm64: Prevent cpu hotplug rwsem recursion Thomas Gleixner
2017-05-26 8:45 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 27/32] arm: Prevent " Thomas Gleixner
2017-05-26 8:46 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 28/32] s390: " Thomas Gleixner
2017-05-24 10:57 ` Heiko Carstens
2017-05-26 8:46 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 29/32] cpu/hotplug: Convert hotplug locking to percpu rwsem Thomas Gleixner
2017-05-26 8:47 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 30/32] sched: Provide is_percpu_thread() helper Thomas Gleixner
2017-05-26 8:47 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 31/32] acpi/processor: Prevent cpu hotplug deadlock Thomas Gleixner
2017-05-26 8:48 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 8:15 ` [patch V3 32/32] cpuhotplug: Link lock stacks for hotplug callbacks Thomas Gleixner
2017-05-26 8:48 ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2017-05-24 16:22 ` [patch V3 00/32] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Paul E. McKenney
2017-05-26 7:03 ` Ingo Molnar
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