diff options
| -rw-r--r-- | include/linux/cpumask.h | 2 | ||||
| -rw-r--r-- | lib/cpumask.c | 64 |
2 files changed, 66 insertions, 0 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d08e4d2..3551d66 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -257,6 +257,8 @@ static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) set_bit(cpumask_check(cpu), cpumask_bits(dstp)); } +int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp); + /** * cpumask_clear_cpu - clear a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) diff --git a/lib/cpumask.c b/lib/cpumask.c index b810b75..14049a9 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -163,4 +163,68 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask) { memblock_free_early(__pa(mask), cpumask_size()); } + +/** + * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first + * + * @i: index number + * @numa_node: local numa_node + * @dstp: cpumask with the relevant cpu bit set according to the policy + * + * This function sets the cpumask according to a numa aware policy. + * cpumask could be used as an affinity hint for the IRQ related to a + * queue. When the policy is to spread queues across cores - local cores + * first. + * + * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set + * the cpu bit and need to re-call the function. + */ +int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp) +{ + cpumask_var_t mask; + int cpu; + int ret = 0; + + if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) + return -ENOMEM; + + i %= num_online_cpus(); + + if (!cpumask_of_node(numa_node)) { + /* Use all online cpu's for non numa aware system */ + cpumask_copy(mask, cpu_online_mask); + } else { + int n; + + cpumask_and(mask, + cpumask_of_node(numa_node), cpu_online_mask); + + n = cpumask_weight(mask); + if (i >= n) { + i -= n; + + /* If index > number of local cpu's, mask out local + * cpu's + */ + cpumask_andnot(mask, cpu_online_mask, mask); + } + } + + for_each_cpu(cpu, mask) { + if (--i < 0) + goto out; + } + + ret = -EAGAIN; + +out: + free_cpumask_var(mask); + + if (!ret) + cpumask_set_cpu(cpu, dstp); + + return ret; +} +EXPORT_SYMBOL(cpumask_set_cpu_local_first); + #endif |