#include <linux/slab.h>
#include <linux/cpu.h>
-static int get_first_sibling(unsigned int cpu)
+static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
+ int cpus_per_vec)
{
- unsigned int ret;
+ const struct cpumask *siblmsk;
+ int cpu, sibl;
- ret = cpumask_first(topology_sibling_cpumask(cpu));
- if (ret < nr_cpu_ids)
- return ret;
- return cpu;
+ for ( ; cpus_per_vec > 0; ) {
+ cpu = cpumask_first(nmsk);
+
+ /* Should not happen, but I'm too lazy to think about it */
+ if (cpu >= nr_cpu_ids)
+ return;
+
+ cpumask_clear_cpu(cpu, nmsk);
+ cpumask_set_cpu(cpu, irqmsk);
+ cpus_per_vec--;
+
+ /* If the cpu has siblings, use them first */
+ siblmsk = topology_sibling_cpumask(cpu);
+ for (sibl = -1; cpus_per_vec > 0; ) {
+ sibl = cpumask_next(sibl, siblmsk);
+ if (sibl >= nr_cpu_ids)
+ break;
+ if (!cpumask_test_and_clear_cpu(sibl, nmsk))
+ continue;
+ cpumask_set_cpu(sibl, irqmsk);
+ cpus_per_vec--;
+ }
+ }
+}
+
+static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk)
+{
+ int n, nodes;
+
+ /* Calculate the number of nodes in the supplied affinity mask */
+ for (n = 0, nodes = 0; n < num_online_nodes(); n++) {
+ if (cpumask_intersects(mask, cpumask_of_node(n))) {
+ node_set(n, *nodemsk);
+ nodes++;
+ }
+ }
+ return nodes;
}
-/*
- * Take a map of online CPUs and the number of available interrupt vectors
- * and generate an output cpumask suitable for spreading MSI/MSI-X vectors
- * so that they are distributed as good as possible around the CPUs. If
- * more vectors than CPUs are available we'll map one to each CPU,
- * otherwise we map one to the first sibling of each socket.
+/**
+ * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
+ * @affinity: The affinity mask to spread. If NULL cpu_online_mask
+ * is used
+ * @nvecs: The number of vectors
*
- * If there are more vectors than CPUs we will still only have one bit
- * set per CPU, but interrupt code will keep on assigning the vectors from
- * the start of the bitmap until we run out of vectors.
+ * Returns the masks pointer or NULL if allocation failed.
*/
-struct cpumask *irq_create_affinity_mask(unsigned int *nr_vecs)
+struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity,
+ int nvec)
{
- struct cpumask *affinity_mask;
- unsigned int max_vecs = *nr_vecs;
+ int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec = 0;
+ nodemask_t nodemsk = NODE_MASK_NONE;
+ struct cpumask *masks;
+ cpumask_var_t nmsk;
- if (max_vecs == 1)
+ if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
return NULL;
- affinity_mask = kzalloc(cpumask_size(), GFP_KERNEL);
- if (!affinity_mask) {
- *nr_vecs = 1;
- return NULL;
- }
+ masks = kzalloc(nvec * sizeof(*masks), GFP_KERNEL);
+ if (!masks)
+ goto out;
+ /* Stabilize the cpumasks */
get_online_cpus();
- if (max_vecs >= num_online_cpus()) {
- cpumask_copy(affinity_mask, cpu_online_mask);
- *nr_vecs = num_online_cpus();
- } else {
- unsigned int vecs = 0, cpu;
-
- for_each_online_cpu(cpu) {
- if (cpu == get_first_sibling(cpu)) {
- cpumask_set_cpu(cpu, affinity_mask);
- vecs++;
- }
+ /* If the supplied affinity mask is NULL, use cpu online mask */
+ if (!affinity)
+ affinity = cpu_online_mask;
+
+ nodes = get_nodes_in_cpumask(affinity, &nodemsk);
- if (--max_vecs == 0)
+ /*
+ * If the number of nodes in the mask is less than or equal the
+ * number of vectors we just spread the vectors across the nodes.
+ */
+ if (nvec <= nodes) {
+ for_each_node_mask(n, nodemsk) {
+ cpumask_copy(masks + curvec, cpumask_of_node(n));
+ if (++curvec == nvec)
break;
}
- *nr_vecs = vecs;
+ goto outonl;
}
+
+ /* Spread the vectors per node */
+ vecs_per_node = nvec / nodes;
+ /* Account for rounding errors */
+ extra_vecs = nvec - (nodes * vecs_per_node);
+
+ for_each_node_mask(n, nodemsk) {
+ int ncpus, v, vecs_to_assign = vecs_per_node;
+
+ /* Get the cpus on this node which are in the mask */
+ cpumask_and(nmsk, affinity, cpumask_of_node(n));
+
+ /* Calculate the number of cpus per vector */
+ ncpus = cpumask_weight(nmsk);
+
+ for (v = 0; curvec < nvec && v < vecs_to_assign; curvec++, v++) {
+ cpus_per_vec = ncpus / vecs_to_assign;
+
+ /* Account for extra vectors to compensate rounding errors */
+ if (extra_vecs) {
+ cpus_per_vec++;
+ if (!--extra_vecs)
+ vecs_per_node++;
+ }
+ irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
+ }
+
+ if (curvec >= nvec)
+ break;
+ }
+
+outonl:
put_online_cpus();
+out:
+ free_cpumask_var(nmsk);
+ return masks;
+}
+
+/**
+ * irq_calc_affinity_vectors - Calculate to optimal number of vectors for a given affinity mask
+ * @affinity: The affinity mask to spread. If NULL cpu_online_mask
+ * is used
+ * @maxvec: The maximum number of vectors available
+ */
+int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec)
+{
+ int cpus, ret;
- return affinity_mask;
+ /* Stabilize the cpumasks */
+ get_online_cpus();
+ /* If the supplied affinity mask is NULL, use cpu online mask */
+ if (!affinity)
+ affinity = cpu_online_mask;
+
+ cpus = cpumask_weight(affinity);
+ ret = (cpus < maxvec) ? cpus : maxvec;
+
+ put_online_cpus();
+ return ret;
}
projects / cascardo / linux.git / blobdiff