1 2 #include <linux/interrupt.h> 3 #include <linux/kernel.h> 4 #include <linux/slab.h> 5 #include <linux/cpu.h> 6 7 static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk, 8 int cpus_per_vec) 9 { 10 const struct cpumask *siblmsk; 11 int cpu, sibl; 12 13 for ( ; cpus_per_vec > 0; ) { 14 cpu = cpumask_first(nmsk); 15 16 /* Should not happen, but I'm too lazy to think about it */ 17 if (cpu >= nr_cpu_ids) 18 return; 19 20 cpumask_clear_cpu(cpu, nmsk); 21 cpumask_set_cpu(cpu, irqmsk); 22 cpus_per_vec--; 23 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) 29 break; 30 if (!cpumask_test_and_clear_cpu(sibl, nmsk)) 31 continue; 32 cpumask_set_cpu(sibl, irqmsk); 33 cpus_per_vec--; 34 } 35 } 36 } 37 38 static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk) 39 { 40 int n, nodes = 0; 41 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); 46 nodes++; 47 } 48 } 49 return nodes; 50 } 51 52 /** 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 56 * 57 * Returns the masks pointer or NULL if allocation failed. 58 */ 59 struct cpumask * 60 irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) 61 { 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; 67 cpumask_var_t nmsk; 68 69 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL)) 70 return NULL; 71 72 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL); 73 if (!masks) 74 goto out; 75 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); 79 80 /* Stabilize the cpumasks */ 81 get_online_cpus(); 82 nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk); 83 84 /* 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. 87 */ 88 if (affv <= nodes) { 89 for_each_node_mask(n, nodemsk) { 90 cpumask_copy(masks + curvec, cpumask_of_node(n)); 91 if (++curvec == last_affv) 92 break; 93 } 94 goto done; 95 } 96 97 for_each_node_mask(n, nodemsk) { 98 int ncpus, v, vecs_to_assign, vecs_per_node; 99 100 /* Spread the vectors per node */ 101 vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes; 102 103 /* Get the cpus on this node which are in the mask */ 104 cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n)); 105 106 /* Calculate the number of cpus per vector */ 107 ncpus = cpumask_weight(nmsk); 108 vecs_to_assign = min(vecs_per_node, ncpus); 109 110 /* Account for rounding errors */ 111 extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign); 112 113 for (v = 0; curvec < last_affv && v < vecs_to_assign; 114 curvec++, v++) { 115 cpus_per_vec = ncpus / vecs_to_assign; 116 117 /* Account for extra vectors to compensate rounding errors */ 118 if (extra_vecs) { 119 cpus_per_vec++; 120 --extra_vecs; 121 } 122 irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec); 123 } 124 125 if (curvec >= last_affv) 126 break; 127 --nodes; 128 } 129 130 done: 131 put_online_cpus(); 132 133 /* Fill out vectors at the end that don't need affinity */ 134 for (; curvec < nvecs; curvec++) 135 cpumask_copy(masks + curvec, irq_default_affinity); 136 out: 137 free_cpumask_var(nmsk); 138 return masks; 139 } 140 141 /** 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 145 */ 146 int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd) 147 { 148 int resv = affd->pre_vectors + affd->post_vectors; 149 int vecs = maxvec - resv; 150 int cpus; 151 152 /* Stabilize the cpumasks */ 153 get_online_cpus(); 154 cpus = cpumask_weight(cpu_online_mask); 155 put_online_cpus(); 156 157 return min(cpus, vecs) + resv; 158 } 159