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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2016 Thomas Gleixner.
4 * Copyright (C) 2016-2017 Christoph Hellwig.
5 */
6#include <linux/interrupt.h>
7#include <linux/kernel.h>
8#include <linux/slab.h>
9#include <linux/cpu.h>
10
11static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
12 int cpus_per_vec)
13{
14 const struct cpumask *siblmsk;
15 int cpu, sibl;
16
17 for ( ; cpus_per_vec > 0; ) {
18 cpu = cpumask_first(nmsk);
19
20 /* Should not happen, but I'm too lazy to think about it */
21 if (cpu >= nr_cpu_ids)
22 return;
23
24 cpumask_clear_cpu(cpu, nmsk);
25 cpumask_set_cpu(cpu, irqmsk);
26 cpus_per_vec--;
27
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)
33 break;
34 if (!cpumask_test_and_clear_cpu(sibl, nmsk))
35 continue;
36 cpumask_set_cpu(sibl, irqmsk);
37 cpus_per_vec--;
38 }
39 }
40}
41
42static cpumask_var_t *alloc_node_to_cpumask(void)
43{
44 cpumask_var_t *masks;
45 int node;
46
47 masks = kcalloc(nr_node_ids, sizeof(cpumask_var_t), GFP_KERNEL);
48 if (!masks)
49 return NULL;
50
51 for (node = 0; node < nr_node_ids; node++) {
52 if (!zalloc_cpumask_var(&masks[node], GFP_KERNEL))
53 goto out_unwind;
54 }
55
56 return masks;
57
58out_unwind:
59 while (--node >= 0)
60 free_cpumask_var(masks[node]);
61 kfree(masks);
62 return NULL;
63}
64
65static void free_node_to_cpumask(cpumask_var_t *masks)
66{
67 int node;
68
69 for (node = 0; node < nr_node_ids; node++)
70 free_cpumask_var(masks[node]);
71 kfree(masks);
72}
73
74static void build_node_to_cpumask(cpumask_var_t *masks)
75{
76 int cpu;
77
78 for_each_possible_cpu(cpu)
79 cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]);
80}
81
82static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask,
83 const struct cpumask *mask, nodemask_t *nodemsk)
84{
85 int n, nodes = 0;
86
87 /* Calculate the number of nodes in the supplied affinity mask */
88 for_each_node(n) {
89 if (cpumask_intersects(mask, node_to_cpumask[n])) {
90 node_set(n, *nodemsk);
91 nodes++;
92 }
93 }
94 return nodes;
95}
96
97static int irq_build_affinity_masks(const struct irq_affinity *affd,
98 int startvec, int numvecs,
99 cpumask_var_t *node_to_cpumask,
100 const struct cpumask *cpu_mask,
101 struct cpumask *nmsk,
102 struct cpumask *masks)
103{
104 int n, nodes, cpus_per_vec, extra_vecs, done = 0;
105 int last_affv = affd->pre_vectors + numvecs;
106 int curvec = startvec;
107 nodemask_t nodemsk = NODE_MASK_NONE;
108
109 if (!cpumask_weight(cpu_mask))
110 return 0;
111
112 nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);
113
114 /*
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.
117 */
118 if (numvecs <= nodes) {
119 for_each_node_mask(n, nodemsk) {
120 cpumask_copy(masks + curvec, node_to_cpumask[n]);
121 if (++done == numvecs)
122 break;
123 if (++curvec == last_affv)
124 curvec = affd->pre_vectors;
125 }
126 goto out;
127 }
128
129 for_each_node_mask(n, nodemsk) {
130 int ncpus, v, vecs_to_assign, vecs_per_node;
131
132 /* Spread the vectors per node */
133 vecs_per_node = (numvecs - (curvec - affd->pre_vectors)) / nodes;
134
135 /* Get the cpus on this node which are in the mask */
136 cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
137
138 /* Calculate the number of cpus per vector */
139 ncpus = cpumask_weight(nmsk);
140 vecs_to_assign = min(vecs_per_node, ncpus);
141
142 /* Account for rounding errors */
143 extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
144
145 for (v = 0; curvec < last_affv && v < vecs_to_assign;
146 curvec++, v++) {
147 cpus_per_vec = ncpus / vecs_to_assign;
148
149 /* Account for extra vectors to compensate rounding errors */
150 if (extra_vecs) {
151 cpus_per_vec++;
152 --extra_vecs;
153 }
154 irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
155 }
156
157 done += v;
158 if (done >= numvecs)
159 break;
160 if (curvec >= last_affv)
161 curvec = affd->pre_vectors;
162 --nodes;
163 }
164
165out:
166 return done;
167}
168
169/**
170 * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
171 * @nvecs: The total number of vectors
172 * @affd: Description of the affinity requirements
173 *
174 * Returns the masks pointer or NULL if allocation failed.
175 */
176struct cpumask *
177irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
178{
179 int affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
180 int curvec, usedvecs;
181 cpumask_var_t nmsk, npresmsk, *node_to_cpumask;
182 struct cpumask *masks = NULL;
183
184 /*
185 * If there aren't any vectors left after applying the pre/post
186 * vectors don't bother with assigning affinity.
187 */
188 if (nvecs == affd->pre_vectors + affd->post_vectors)
189 return NULL;
190
191 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
192 return NULL;
193
194 if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
195 goto outcpumsk;
196
197 node_to_cpumask = alloc_node_to_cpumask();
198 if (!node_to_cpumask)
199 goto outnpresmsk;
200
201 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
202 if (!masks)
203 goto outnodemsk;
204
205 /* Fill out vectors at the beginning that don't need affinity */
206 for (curvec = 0; curvec < affd->pre_vectors; curvec++)
207 cpumask_copy(masks + curvec, irq_default_affinity);
208
209 /* Stabilize the cpumasks */
210 get_online_cpus();
211 build_node_to_cpumask(node_to_cpumask);
212
213 /* Spread on present CPUs starting from affd->pre_vectors */
214 usedvecs = irq_build_affinity_masks(affd, curvec, affvecs,
215 node_to_cpumask, cpu_present_mask,
216 nmsk, masks);
217
218 /*
219 * Spread on non present CPUs starting from the next vector to be
220 * handled. If the spreading of present CPUs already exhausted the
221 * vector space, assign the non present CPUs to the already spread
222 * out vectors.
223 */
224 if (usedvecs >= affvecs)
225 curvec = affd->pre_vectors;
226 else
227 curvec = affd->pre_vectors + usedvecs;
228 cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
229 usedvecs += irq_build_affinity_masks(affd, curvec, affvecs,
230 node_to_cpumask, npresmsk,
231 nmsk, masks);
232 put_online_cpus();
233
234 /* Fill out vectors at the end that don't need affinity */
235 if (usedvecs >= affvecs)
236 curvec = affd->pre_vectors + affvecs;
237 else
238 curvec = affd->pre_vectors + usedvecs;
239 for (; curvec < nvecs; curvec++)
240 cpumask_copy(masks + curvec, irq_default_affinity);
241
242outnodemsk:
243 free_node_to_cpumask(node_to_cpumask);
244outnpresmsk:
245 free_cpumask_var(npresmsk);
246outcpumsk:
247 free_cpumask_var(nmsk);
248 return masks;
249}
250
251/**
252 * irq_calc_affinity_vectors - Calculate the optimal number of vectors
253 * @minvec: The minimum number of vectors available
254 * @maxvec: The maximum number of vectors available
255 * @affd: Description of the affinity requirements
256 */
257int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
258{
259 int resv = affd->pre_vectors + affd->post_vectors;
260 int vecs = maxvec - resv;
261 int ret;
262
263 if (resv > minvec)
264 return 0;
265
266 get_online_cpus();
267 ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv;
268 put_online_cpus();
269 return ret;
270}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2016 Thomas Gleixner.
4 * Copyright (C) 2016-2017 Christoph Hellwig.
5 */
6#include <linux/interrupt.h>
7#include <linux/kernel.h>
8#include <linux/slab.h>
9#include <linux/cpu.h>
10#include <linux/group_cpus.h>
11
12static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
13{
14 affd->nr_sets = 1;
15 affd->set_size[0] = affvecs;
16}
17
18/**
19 * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
20 * @nvecs: The total number of vectors
21 * @affd: Description of the affinity requirements
22 *
23 * Returns the irq_affinity_desc pointer or NULL if allocation failed.
24 */
25struct irq_affinity_desc *
26irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
27{
28 unsigned int affvecs, curvec, usedvecs, i;
29 struct irq_affinity_desc *masks = NULL;
30
31 /*
32 * Determine the number of vectors which need interrupt affinities
33 * assigned. If the pre/post request exhausts the available vectors
34 * then nothing to do here except for invoking the calc_sets()
35 * callback so the device driver can adjust to the situation.
36 */
37 if (nvecs > affd->pre_vectors + affd->post_vectors)
38 affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
39 else
40 affvecs = 0;
41
42 /*
43 * Simple invocations do not provide a calc_sets() callback. Install
44 * the generic one.
45 */
46 if (!affd->calc_sets)
47 affd->calc_sets = default_calc_sets;
48
49 /* Recalculate the sets */
50 affd->calc_sets(affd, affvecs);
51
52 if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
53 return NULL;
54
55 /* Nothing to assign? */
56 if (!affvecs)
57 return NULL;
58
59 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
60 if (!masks)
61 return NULL;
62
63 /* Fill out vectors at the beginning that don't need affinity */
64 for (curvec = 0; curvec < affd->pre_vectors; curvec++)
65 cpumask_copy(&masks[curvec].mask, irq_default_affinity);
66
67 /*
68 * Spread on present CPUs starting from affd->pre_vectors. If we
69 * have multiple sets, build each sets affinity mask separately.
70 */
71 for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
72 unsigned int this_vecs = affd->set_size[i];
73 int j;
74 struct cpumask *result = group_cpus_evenly(this_vecs);
75
76 if (!result) {
77 kfree(masks);
78 return NULL;
79 }
80
81 for (j = 0; j < this_vecs; j++)
82 cpumask_copy(&masks[curvec + j].mask, &result[j]);
83 kfree(result);
84
85 curvec += this_vecs;
86 usedvecs += this_vecs;
87 }
88
89 /* Fill out vectors at the end that don't need affinity */
90 if (usedvecs >= affvecs)
91 curvec = affd->pre_vectors + affvecs;
92 else
93 curvec = affd->pre_vectors + usedvecs;
94 for (; curvec < nvecs; curvec++)
95 cpumask_copy(&masks[curvec].mask, irq_default_affinity);
96
97 /* Mark the managed interrupts */
98 for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
99 masks[i].is_managed = 1;
100
101 return masks;
102}
103
104/**
105 * irq_calc_affinity_vectors - Calculate the optimal number of vectors
106 * @minvec: The minimum number of vectors available
107 * @maxvec: The maximum number of vectors available
108 * @affd: Description of the affinity requirements
109 */
110unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
111 const struct irq_affinity *affd)
112{
113 unsigned int resv = affd->pre_vectors + affd->post_vectors;
114 unsigned int set_vecs;
115
116 if (resv > minvec)
117 return 0;
118
119 if (affd->calc_sets) {
120 set_vecs = maxvec - resv;
121 } else {
122 cpus_read_lock();
123 set_vecs = cpumask_weight(cpu_possible_mask);
124 cpus_read_unlock();
125 }
126
127 return resv + min(set_vecs, maxvec - resv);
128}