1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2016 Thomas Gleixner.
4 * Copyright (C) 2016-2017 Christoph Hellwig.
6 #include <linux/interrupt.h>
7 #include <linux/kernel.h>
8 #include <linux/slab.h>
11 static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
14 const struct cpumask *siblmsk;
17 for ( ; cpus_per_vec > 0; ) {
18 cpu = cpumask_first(nmsk);
20 /* Should not happen, but I'm too lazy to think about it */
21 if (cpu >= nr_cpu_ids)
24 cpumask_clear_cpu(cpu, nmsk);
25 cpumask_set_cpu(cpu, irqmsk);
28 /* If the cpu has siblings, use them first */
29 siblmsk = topology_sibling_cpumask(cpu);
30 for (sibl = -1; cpus_per_vec > 0; ) {
31 sibl = cpumask_next(sibl, siblmsk);
32 if (sibl >= nr_cpu_ids)
34 if (!cpumask_test_and_clear_cpu(sibl, nmsk))
36 cpumask_set_cpu(sibl, irqmsk);
42 static cpumask_var_t *alloc_node_to_cpumask(void)
47 masks = kcalloc(nr_node_ids, sizeof(cpumask_var_t), GFP_KERNEL);
51 for (node = 0; node < nr_node_ids; node++) {
52 if (!zalloc_cpumask_var(&masks[node], GFP_KERNEL))
60 free_cpumask_var(masks[node]);
65 static void free_node_to_cpumask(cpumask_var_t *masks)
69 for (node = 0; node < nr_node_ids; node++)
70 free_cpumask_var(masks[node]);
74 static void build_node_to_cpumask(cpumask_var_t *masks)
78 for_each_possible_cpu(cpu)
79 cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]);
82 static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask,
83 const struct cpumask *mask, nodemask_t *nodemsk)
87 /* Calculate the number of nodes in the supplied affinity mask */
89 if (cpumask_intersects(mask, node_to_cpumask[n])) {
90 node_set(n, *nodemsk);
97 static int __irq_build_affinity_masks(const struct irq_affinity *affd,
98 int startvec, int numvecs, int firstvec,
99 cpumask_var_t *node_to_cpumask,
100 const struct cpumask *cpu_mask,
101 struct cpumask *nmsk,
102 struct irq_affinity_desc *masks)
104 int n, nodes, cpus_per_vec, extra_vecs, done = 0;
105 int last_affv = firstvec + numvecs;
106 int curvec = startvec;
107 nodemask_t nodemsk = NODE_MASK_NONE;
109 if (!cpumask_weight(cpu_mask))
112 nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);
115 * If the number of nodes in the mask is greater than or equal the
116 * number of vectors we just spread the vectors across the nodes.
118 if (numvecs <= nodes) {
119 for_each_node_mask(n, nodemsk) {
120 cpumask_or(&masks[curvec].mask,
123 if (++curvec == last_affv)
130 for_each_node_mask(n, nodemsk) {
131 int ncpus, v, vecs_to_assign, vecs_per_node;
133 /* Spread the vectors per node */
134 vecs_per_node = (numvecs - (curvec - firstvec)) / nodes;
136 /* Get the cpus on this node which are in the mask */
137 cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
139 /* Calculate the number of cpus per vector */
140 ncpus = cpumask_weight(nmsk);
141 vecs_to_assign = min(vecs_per_node, ncpus);
143 /* Account for rounding errors */
144 extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
146 for (v = 0; curvec < last_affv && v < vecs_to_assign;
148 cpus_per_vec = ncpus / vecs_to_assign;
150 /* Account for extra vectors to compensate rounding errors */
155 irq_spread_init_one(&masks[curvec].mask, nmsk,
162 if (curvec >= last_affv)
172 * build affinity in two stages:
173 * 1) spread present CPU on these vectors
174 * 2) spread other possible CPUs on these vectors
176 static int irq_build_affinity_masks(const struct irq_affinity *affd,
177 int startvec, int numvecs, int firstvec,
178 cpumask_var_t *node_to_cpumask,
179 struct irq_affinity_desc *masks)
181 int curvec = startvec, nr_present, nr_others;
183 cpumask_var_t nmsk, npresmsk;
185 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
188 if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
192 /* Stabilize the cpumasks */
194 build_node_to_cpumask(node_to_cpumask);
196 /* Spread on present CPUs starting from affd->pre_vectors */
197 nr_present = __irq_build_affinity_masks(affd, curvec, numvecs,
198 firstvec, node_to_cpumask,
199 cpu_present_mask, nmsk, masks);
202 * Spread on non present CPUs starting from the next vector to be
203 * handled. If the spreading of present CPUs already exhausted the
204 * vector space, assign the non present CPUs to the already spread
207 if (nr_present >= numvecs)
210 curvec = firstvec + nr_present;
211 cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
212 nr_others = __irq_build_affinity_masks(affd, curvec, numvecs,
213 firstvec, node_to_cpumask,
214 npresmsk, nmsk, masks);
217 if (nr_present < numvecs)
218 WARN_ON(nr_present + nr_others < numvecs);
220 free_cpumask_var(npresmsk);
223 free_cpumask_var(nmsk);
228 * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
229 * @nvecs: The total number of vectors
230 * @affd: Description of the affinity requirements
232 * Returns the irq_affinity_desc pointer or NULL if allocation failed.
234 struct irq_affinity_desc *
235 irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
237 int affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
238 int curvec, usedvecs;
239 cpumask_var_t *node_to_cpumask;
240 struct irq_affinity_desc *masks = NULL;
244 * If there aren't any vectors left after applying the pre/post
245 * vectors don't bother with assigning affinity.
247 if (nvecs == affd->pre_vectors + affd->post_vectors)
250 node_to_cpumask = alloc_node_to_cpumask();
251 if (!node_to_cpumask)
254 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
258 /* Fill out vectors at the beginning that don't need affinity */
259 for (curvec = 0; curvec < affd->pre_vectors; curvec++)
260 cpumask_copy(&masks[curvec].mask, irq_default_affinity);
262 * Spread on present CPUs starting from affd->pre_vectors. If we
263 * have multiple sets, build each sets affinity mask separately.
265 nr_sets = affd->nr_sets;
269 for (i = 0, usedvecs = 0; i < nr_sets; i++) {
270 int this_vecs = affd->sets ? affd->sets[i] : affvecs;
273 ret = irq_build_affinity_masks(affd, curvec, this_vecs,
274 curvec, node_to_cpumask, masks);
281 usedvecs += this_vecs;
284 /* Fill out vectors at the end that don't need affinity */
285 if (usedvecs >= affvecs)
286 curvec = affd->pre_vectors + affvecs;
288 curvec = affd->pre_vectors + usedvecs;
289 for (; curvec < nvecs; curvec++)
290 cpumask_copy(&masks[curvec].mask, irq_default_affinity);
292 /* Mark the managed interrupts */
293 for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
294 masks[i].is_managed = 1;
297 free_node_to_cpumask(node_to_cpumask);
302 * irq_calc_affinity_vectors - Calculate the optimal number of vectors
303 * @minvec: The minimum number of vectors available
304 * @maxvec: The maximum number of vectors available
305 * @affd: Description of the affinity requirements
307 int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
309 int resv = affd->pre_vectors + affd->post_vectors;
310 int vecs = maxvec - resv;
319 for (i = 0, set_vecs = 0; i < affd->nr_sets; i++)
320 set_vecs += affd->sets[i];
323 set_vecs = cpumask_weight(cpu_possible_mask);
327 return resv + min(set_vecs, vecs);