diff options
| -rw-r--r-- | include/linux/smp.h | 11 | ||||
| -rw-r--r-- | kernel/smp.c | 45 |
2 files changed, 55 insertions, 1 deletions
diff --git a/include/linux/smp.h b/include/linux/smp.h index 39c64ba..7a0570e 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -76,6 +76,9 @@ void smp_call_function_many(const struct cpumask *mask, void __smp_call_function_single(int cpuid, struct call_single_data *data, int wait); +int smp_call_function_any(const struct cpumask *mask, + void (*func)(void *info), void *info, int wait); + /* * Generic and arch helpers */ @@ -137,9 +140,15 @@ static inline void smp_send_reschedule(int cpu) { } #define smp_prepare_boot_cpu() do {} while (0) #define smp_call_function_many(mask, func, info, wait) \ (up_smp_call_function(func, info)) -static inline void init_call_single_data(void) +static inline void init_call_single_data(void) { } + +static inline int +smp_call_function_any(const struct cpumask *mask, void (*func)(void *info), + void *info, int wait) { + return smp_call_function_single(0, func, info, wait); } + #endif /* !SMP */ /* diff --git a/kernel/smp.c b/kernel/smp.c index 8bd618f..a8c7606 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -319,6 +319,51 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, } EXPORT_SYMBOL(smp_call_function_single); +/* + * smp_call_function_any - Run a function on any of the given cpus + * @mask: The mask of cpus it can run on. + * @func: The function to run. This must be fast and non-blocking. + * @info: An arbitrary pointer to pass to the function. + * @wait: If true, wait until function has completed. + * + * Returns 0 on success, else a negative status code (if no cpus were online). + * Note that @wait will be implicitly turned on in case of allocation failures, + * since we fall back to on-stack allocation. + * + * Selection preference: + * 1) current cpu if in @mask + * 2) any cpu of current node if in @mask + * 3) any other online cpu in @mask + */ +int smp_call_function_any(const struct cpumask *mask, + void (*func)(void *info), void *info, int wait) +{ + unsigned int cpu; + const struct cpumask *nodemask; + int ret; + + /* Try for same CPU (cheapest) */ + cpu = get_cpu(); + if (cpumask_test_cpu(cpu, mask)) + goto call; + + /* Try for same node. */ + nodemask = cpumask_of_node(cpu); + for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; + cpu = cpumask_next_and(cpu, nodemask, mask)) { + if (cpu_online(cpu)) + goto call; + } + + /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ + cpu = cpumask_any_and(mask, cpu_online_mask); +call: + ret = smp_call_function_single(cpu, func, info, wait); + put_cpu(); + return ret; +} +EXPORT_SYMBOL_GPL(smp_call_function_any); + /** * __smp_call_function_single(): Run a function on another CPU * @cpu: The CPU to run on. |
