#include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/cpu.h> static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk, int cpus_per_vec) { const struct cpumask *siblmsk; int cpu, sibl; 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 = 0; /* Calculate the number of nodes in the supplied affinity mask */ for_each_online_node(n) { if (cpumask_intersects(mask, cpumask_of_node(n))) { node_set(n, *nodemsk); nodes++; } } return nodes; } /** * irq_create_affinity_masks - Create affinity masks for multiqueue spreading * @nvecs: The total number of vectors * @affd: Description of the affinity requirements * * Returns the masks pointer or NULL if allocation failed. */ struct cpumask * irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) { int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec; int affv = nvecs - affd->pre_vectors - affd->post_vectors; int last_affv = affv + affd->pre_vectors; nodemask_t nodemsk = NODE_MASK_NONE; struct cpumask *masks; cpumask_var_t nmsk; if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL)) return NULL; masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL); if (!masks) goto out; /* Fill out vectors at the beginning that don't need affinity */ for (curvec = 0; curvec < affd->pre_vectors; curvec++) cpumask_copy(masks + curvec, irq_default_affinity); /* Stabilize the cpumasks */ get_online_cpus(); nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk); /* * If the number of nodes in the mask is greater than or equal the * number of vectors we just spread the vectors across the nodes. */ if (affv <= nodes) { for_each_node_mask(n, nodemsk) { cpumask_copy(masks + curvec, cpumask_of_node(n)); if (++curvec == last_affv) break; } goto done; } /* Spread the vectors per node */ vecs_per_node = affv / nodes; /* Account for rounding errors */ extra_vecs = affv - (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, cpu_online_mask, cpumask_of_node(n)); /* Calculate the number of cpus per vector */ ncpus = cpumask_weight(nmsk); for (v = 0; curvec < last_affv && 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 >= last_affv) break; } done: put_online_cpus(); /* Fill out vectors at the end that don't need affinity */ for (; curvec < nvecs; curvec++) cpumask_copy(masks + curvec, irq_default_affinity); out: free_cpumask_var(nmsk); return masks; } /** * irq_calc_affinity_vectors - Calculate the optimal number of vectors * @maxvec: The maximum number of vectors available * @affd: Description of the affinity requirements */ int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd) { int resv = affd->pre_vectors + affd->post_vectors; int vecs = maxvec - resv; int cpus; /* Stabilize the cpumasks */ get_online_cpus(); cpus = cpumask_weight(cpu_online_mask); put_online_cpus(); return min(cpus, vecs) + resv; }