Messages in this thread Patch in this message | | | From | Chuansheng Liu <> | Subject | [PATCH 2/3] smp: Adding new function wake_up_all_cpus() | Date | Mon, 18 Aug 2014 16:37:31 +0800 |
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Currently kick_all_cpus_sync() can break non-polling idle cpus thru IPI interrupts.
But sometimes we need to break the polling idle cpus immediately to reselect the suitable c-state, also for non-idle cpus, we need to do nothing if we try to wake up them.
Here adding one new function wake_up_all_cpus() to let all cpus out of idle based on function wake_up_if_idle().
Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> --- include/linux/smp.h | 2 ++ kernel/smp.c | 22 ++++++++++++++++++++++ 2 files changed, 24 insertions(+)
diff --git a/include/linux/smp.h b/include/linux/smp.h index 34347f2..1cfb1fd 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -100,6 +100,7 @@ int smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, void *info, int wait); void kick_all_cpus_sync(void); +void wake_up_all_cpus(void); /* * Generic and arch helpers @@ -148,6 +149,7 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, } static inline void kick_all_cpus_sync(void) { } +static inline void wake_up_all_cpus(void) { } #endif /* !SMP */ diff --git a/kernel/smp.c b/kernel/smp.c index aff8aa1..1e69507 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -13,6 +13,7 @@ #include <linux/gfp.h> #include <linux/smp.h> #include <linux/cpu.h> +#include <linux/sched.h> #include "smpboot.h" @@ -699,3 +700,24 @@ void kick_all_cpus_sync(void) smp_call_function(do_nothing, NULL, 1); } EXPORT_SYMBOL_GPL(kick_all_cpus_sync); + +/** + * wake_up_all_cpus - break all cpus out of idle + * wake_up_all_cpus try to break all cpus which is in idle state even + * including idle polling cpus, for non-idle cpus, we will do nothing + * for them. + */ +void wake_up_all_cpus(void) +{ + int cpu; + + preempt_disable(); + for_each_online_cpu(cpu) { + if (cpu == smp_processor_id()) + continue; + + wake_up_if_idle(cpu); + } + preempt_enable(); +} +EXPORT_SYMBOL_GPL(wake_up_all_cpus); -- 1.7.9.5
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