mirror of https://gitee.com/openkylin/linux.git
155 lines
3.7 KiB
C
155 lines
3.7 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;
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/* Calculate the number of nodes in the supplied affinity mask */
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for (n = 0, nodes = 0; n < num_online_nodes(); 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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* @affinity: The affinity mask to spread. If NULL cpu_online_mask
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* is used
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* @nvecs: The number of vectors
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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 *irq_create_affinity_masks(const struct cpumask *affinity,
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int nvec)
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{
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int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec = 0;
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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 = kzalloc(nvec * sizeof(*masks), GFP_KERNEL);
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if (!masks)
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goto out;
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/* Stabilize the cpumasks */
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get_online_cpus();
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/* If the supplied affinity mask is NULL, use cpu online mask */
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if (!affinity)
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affinity = cpu_online_mask;
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nodes = get_nodes_in_cpumask(affinity, &nodemsk);
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/*
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* If the number of nodes in the mask is less 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 (nvec <= 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 == nvec)
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break;
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}
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goto outonl;
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}
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/* Spread the vectors per node */
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vecs_per_node = nvec / nodes;
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/* Account for rounding errors */
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extra_vecs = nvec - (nodes * vecs_per_node);
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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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/* Get the cpus on this node which are in the mask */
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cpumask_and(nmsk, affinity, 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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for (v = 0; curvec < nvec && v < vecs_to_assign; 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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if (!--extra_vecs)
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vecs_per_node++;
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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 >= nvec)
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break;
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}
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outonl:
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put_online_cpus();
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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 to optimal number of vectors for a given affinity mask
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* @affinity: The affinity mask to spread. If NULL cpu_online_mask
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* is used
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* @maxvec: The maximum number of vectors available
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*/
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int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec)
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{
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int cpus, ret;
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/* Stabilize the cpumasks */
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get_online_cpus();
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/* If the supplied affinity mask is NULL, use cpu online mask */
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if (!affinity)
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affinity = cpu_online_mask;
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cpus = cpumask_weight(affinity);
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ret = (cpus < maxvec) ? cpus : maxvec;
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put_online_cpus();
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return ret;
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}
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