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-rw-r--r--lib/cpumask.c74
1 files changed, 26 insertions, 48 deletions
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 830dd5dec40f..5f627084f2e9 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -139,64 +139,42 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask)
#endif
/**
- * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first
- *
+ * cpumask_local_spread - select the 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
+ * @node: local numa_node
*
- * 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.
+ * This function selects an online CPU according to a numa aware policy;
+ * local cpus are returned first, followed by non-local ones, then it
+ * wraps around.
*
- * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set
- * the cpu bit and need to re-call the function.
+ * It's not very efficient, but useful for setup.
*/
-int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp)
+unsigned int cpumask_local_spread(unsigned int i, int node)
{
- cpumask_var_t mask;
int cpu;
- int ret = 0;
-
- if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
- return -ENOMEM;
+ /* Wrap: we always want a cpu. */
i %= num_online_cpus();
- if (numa_node == -1 || !cpumask_of_node(numa_node)) {
- /* Use all online cpu's for non numa aware system */
- cpumask_copy(mask, cpu_online_mask);
+ if (node == -1) {
+ for_each_cpu(cpu, cpu_online_mask)
+ if (i-- == 0)
+ return cpu;
} 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);
+ /* NUMA first. */
+ for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
+ if (i-- == 0)
+ return cpu;
+
+ for_each_cpu(cpu, cpu_online_mask) {
+ /* Skip NUMA nodes, done above. */
+ if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
+ continue;
+
+ if (i-- == 0)
+ return cpu;
}
}
-
- 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;
+ BUG();
}
-EXPORT_SYMBOL(cpumask_set_cpu_local_first);
+EXPORT_SYMBOL(cpumask_local_spread);

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