2 #include <linux/interrupt.h>
3 #include <linux/kernel.h>
4 #include <linux/slab.h>
7 static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
10 const struct cpumask *siblmsk;
13 for ( ; cpus_per_vec > 0; ) {
14 cpu = cpumask_first(nmsk);
16 /* Should not happen, but I'm too lazy to think about it */
17 if (cpu >= nr_cpu_ids)
20 cpumask_clear_cpu(cpu, nmsk);
21 cpumask_set_cpu(cpu, irqmsk);
24 /* If the cpu has siblings, use them first */
25 siblmsk = topology_sibling_cpumask(cpu);
26 for (sibl = -1; cpus_per_vec > 0; ) {
27 sibl = cpumask_next(sibl, siblmsk);
28 if (sibl >= nr_cpu_ids)
30 if (!cpumask_test_and_clear_cpu(sibl, nmsk))
32 cpumask_set_cpu(sibl, irqmsk);
38 static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk)
42 /* Calculate the number of nodes in the supplied affinity mask */
43 for_each_online_node(n) {
44 if (cpumask_intersects(mask, cpumask_of_node(n))) {
45 node_set(n, *nodemsk);
53 * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
54 * @nvecs: The total number of vectors
55 * @affd: Description of the affinity requirements
57 * Returns the masks pointer or NULL if allocation failed.
60 irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
62 int n, nodes, cpus_per_vec, extra_vecs, curvec;
63 int affv = nvecs - affd->pre_vectors - affd->post_vectors;
64 int last_affv = affv + affd->pre_vectors;
65 nodemask_t nodemsk = NODE_MASK_NONE;
66 struct cpumask *masks;
69 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
72 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
76 /* Fill out vectors at the beginning that don't need affinity */
77 for (curvec = 0; curvec < affd->pre_vectors; curvec++)
78 cpumask_copy(masks + curvec, irq_default_affinity);
80 /* Stabilize the cpumasks */
82 nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk);
85 * If the number of nodes in the mask is greater than or equal the
86 * number of vectors we just spread the vectors across the nodes.
89 for_each_node_mask(n, nodemsk) {
90 cpumask_copy(masks + curvec, cpumask_of_node(n));
91 if (++curvec == last_affv)
97 for_each_node_mask(n, nodemsk) {
98 int ncpus, v, vecs_to_assign, vecs_per_node;
100 /* Spread the vectors per node */
101 vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;
103 /* Get the cpus on this node which are in the mask */
104 cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n));
106 /* Calculate the number of cpus per vector */
107 ncpus = cpumask_weight(nmsk);
108 vecs_to_assign = min(vecs_per_node, ncpus);
110 /* Account for rounding errors */
111 extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
113 for (v = 0; curvec < last_affv && v < vecs_to_assign;
115 cpus_per_vec = ncpus / vecs_to_assign;
117 /* Account for extra vectors to compensate rounding errors */
122 irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
125 if (curvec >= last_affv)
133 /* Fill out vectors at the end that don't need affinity */
134 for (; curvec < nvecs; curvec++)
135 cpumask_copy(masks + curvec, irq_default_affinity);
137 free_cpumask_var(nmsk);
142 * irq_calc_affinity_vectors - Calculate the optimal number of vectors
143 * @maxvec: The maximum number of vectors available
144 * @affd: Description of the affinity requirements
146 int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
148 int resv = affd->pre_vectors + affd->post_vectors;
149 int vecs = maxvec - resv;
152 /* Stabilize the cpumasks */
154 cpus = cpumask_weight(cpu_online_mask);
157 return min(cpus, vecs) + resv;