159 lines
4.0 KiB
C
159 lines
4.0 KiB
C
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/cpu.h>
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static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
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int cpus_per_vec)
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{
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const struct cpumask *siblmsk;
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int cpu, sibl;
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for ( ; cpus_per_vec > 0; ) {
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cpu = cpumask_first(nmsk);
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/* Should not happen, but I'm too lazy to think about it */
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if (cpu >= nr_cpu_ids)
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return;
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cpumask_clear_cpu(cpu, nmsk);
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cpumask_set_cpu(cpu, irqmsk);
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cpus_per_vec--;
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/* If the cpu has siblings, use them first */
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siblmsk = topology_sibling_cpumask(cpu);
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for (sibl = -1; cpus_per_vec > 0; ) {
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sibl = cpumask_next(sibl, siblmsk);
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if (sibl >= nr_cpu_ids)
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break;
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if (!cpumask_test_and_clear_cpu(sibl, nmsk))
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continue;
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cpumask_set_cpu(sibl, irqmsk);
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cpus_per_vec--;
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}
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}
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}
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static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk)
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{
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int n, nodes = 0;
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/* Calculate the number of nodes in the supplied affinity mask */
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for_each_online_node(n) {
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if (cpumask_intersects(mask, cpumask_of_node(n))) {
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node_set(n, *nodemsk);
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nodes++;
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}
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}
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return nodes;
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}
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/**
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* irq_create_affinity_masks - Create affinity masks for multiqueue spreading
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* @nvecs: The total number of vectors
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* @affd: Description of the affinity requirements
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*
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* Returns the masks pointer or NULL if allocation failed.
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*/
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struct cpumask *
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irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
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{
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int n, nodes, cpus_per_vec, extra_vecs, curvec;
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int affv = nvecs - affd->pre_vectors - affd->post_vectors;
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int last_affv = affv + affd->pre_vectors;
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nodemask_t nodemsk = NODE_MASK_NONE;
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struct cpumask *masks;
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cpumask_var_t nmsk;
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if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
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return NULL;
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masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
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if (!masks)
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goto out;
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/* Fill out vectors at the beginning that don't need affinity */
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for (curvec = 0; curvec < affd->pre_vectors; curvec++)
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cpumask_copy(masks + curvec, irq_default_affinity);
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/* Stabilize the cpumasks */
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get_online_cpus();
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nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk);
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/*
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* If the number of nodes in the mask is greater than or equal the
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* number of vectors we just spread the vectors across the nodes.
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*/
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if (affv <= nodes) {
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for_each_node_mask(n, nodemsk) {
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cpumask_copy(masks + curvec, cpumask_of_node(n));
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if (++curvec == last_affv)
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break;
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}
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goto done;
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}
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for_each_node_mask(n, nodemsk) {
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int ncpus, v, vecs_to_assign, vecs_per_node;
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/* Spread the vectors per node */
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vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;
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/* Get the cpus on this node which are in the mask */
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cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n));
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/* Calculate the number of cpus per vector */
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ncpus = cpumask_weight(nmsk);
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vecs_to_assign = min(vecs_per_node, ncpus);
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/* Account for rounding errors */
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extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
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for (v = 0; curvec < last_affv && v < vecs_to_assign;
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curvec++, v++) {
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cpus_per_vec = ncpus / vecs_to_assign;
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/* Account for extra vectors to compensate rounding errors */
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if (extra_vecs) {
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cpus_per_vec++;
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--extra_vecs;
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}
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irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
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}
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if (curvec >= last_affv)
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break;
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--nodes;
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}
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done:
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put_online_cpus();
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/* Fill out vectors at the end that don't need affinity */
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for (; curvec < nvecs; curvec++)
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cpumask_copy(masks + curvec, irq_default_affinity);
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out:
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free_cpumask_var(nmsk);
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return masks;
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}
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/**
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* irq_calc_affinity_vectors - Calculate the optimal number of vectors
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* @maxvec: The maximum number of vectors available
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* @affd: Description of the affinity requirements
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*/
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int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
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{
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int resv = affd->pre_vectors + affd->post_vectors;
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int vecs = maxvec - resv;
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int cpus;
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/* Stabilize the cpumasks */
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get_online_cpus();
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cpus = cpumask_weight(cpu_online_mask);
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put_online_cpus();
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return min(cpus, vecs) + resv;
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}
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