diff options
Diffstat (limited to 'include/linux/cpumask.h')
| -rw-r--r-- | include/linux/cpumask.h | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 0c7db5efe66c..b5a5a1ed9efd 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -10,6 +10,7 @@ #include <linux/kernel.h> #include <linux/threads.h> #include <linux/bitmap.h> +#include <linux/atomic.h> #include <linux/bug.h> /* Don't assign or return these: may not be this big! */ @@ -95,8 +96,21 @@ extern struct cpumask __cpu_active_mask; #define cpu_present_mask ((const struct cpumask *)&__cpu_present_mask) #define cpu_active_mask ((const struct cpumask *)&__cpu_active_mask) +extern atomic_t __num_online_cpus; + #if NR_CPUS > 1 -#define num_online_cpus() cpumask_weight(cpu_online_mask) +/** + * num_online_cpus() - Read the number of online CPUs + * + * Despite the fact that __num_online_cpus is of type atomic_t, this + * interface gives only a momentary snapshot and is not protected against + * concurrent CPU hotplug operations unless invoked from a cpuhp_lock held + * region. + */ +static inline unsigned int num_online_cpus(void) +{ + return atomic_read(&__num_online_cpus); +} #define num_possible_cpus() cpumask_weight(cpu_possible_mask) #define num_present_cpus() cpumask_weight(cpu_present_mask) #define num_active_cpus() cpumask_weight(cpu_active_mask) @@ -821,14 +835,7 @@ set_cpu_present(unsigned int cpu, bool present) cpumask_clear_cpu(cpu, &__cpu_present_mask); } -static inline void -set_cpu_online(unsigned int cpu, bool online) -{ - if (online) - cpumask_set_cpu(cpu, &__cpu_online_mask); - else - cpumask_clear_cpu(cpu, &__cpu_online_mask); -} +void set_cpu_online(unsigned int cpu, bool online); static inline void set_cpu_active(unsigned int cpu, bool active) |