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 11 static 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 42 static 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 58 out_unwind: 59 while (--node >= 0) 60 free_cpumask_var(masks[node]); 61 kfree(masks); 62 return NULL; 63 } 64 65 static 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 74 static 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 82 static 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 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) 103 { 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; 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_or(&masks[curvec].mask, 121 &masks[curvec].mask, 122 node_to_cpumask[n]); 123 if (++curvec == last_affv) 124 curvec = firstvec; 125 } 126 done = numvecs; 127 goto out; 128 } 129 130 for_each_node_mask(n, nodemsk) { 131 int ncpus, v, vecs_to_assign, vecs_per_node; 132 133 /* Spread the vectors per node */ 134 vecs_per_node = (numvecs - (curvec - firstvec)) / nodes; 135 136 /* Get the cpus on this node which are in the mask */ 137 cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]); 138 139 /* Calculate the number of cpus per vector */ 140 ncpus = cpumask_weight(nmsk); 141 vecs_to_assign = min(vecs_per_node, ncpus); 142 143 /* Account for rounding errors */ 144 extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign); 145 146 for (v = 0; curvec < last_affv && v < vecs_to_assign; 147 curvec++, v++) { 148 cpus_per_vec = ncpus / vecs_to_assign; 149 150 /* Account for extra vectors to compensate rounding errors */ 151 if (extra_vecs) { 152 cpus_per_vec++; 153 --extra_vecs; 154 } 155 irq_spread_init_one(&masks[curvec].mask, nmsk, 156 cpus_per_vec); 157 } 158 159 done += v; 160 if (done >= numvecs) 161 break; 162 if (curvec >= last_affv) 163 curvec = firstvec; 164 --nodes; 165 } 166 167 out: 168 return done; 169 } 170 171 /* 172 * build affinity in two stages: 173 * 1) spread present CPU on these vectors 174 * 2) spread other possible CPUs on these vectors 175 */ 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) 180 { 181 int curvec = startvec, nr_present, nr_others; 182 int ret = -ENOMEM; 183 cpumask_var_t nmsk, npresmsk; 184 185 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL)) 186 return ret; 187 188 if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL)) 189 goto fail; 190 191 ret = 0; 192 /* Stabilize the cpumasks */ 193 get_online_cpus(); 194 build_node_to_cpumask(node_to_cpumask); 195 196 /* 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); 200 201 /* 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 205 * out vectors. 206 */ 207 if (nr_present >= numvecs) 208 curvec = firstvec; 209 else 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); 215 put_online_cpus(); 216 217 if (nr_present < numvecs) 218 WARN_ON(nr_present + nr_others < numvecs); 219 220 free_cpumask_var(npresmsk); 221 222 fail: 223 free_cpumask_var(nmsk); 224 return ret; 225 } 226 227 /** 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 231 * 232 * Returns the irq_affinity_desc pointer or NULL if allocation failed. 233 */ 234 struct irq_affinity_desc * 235 irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) 236 { 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; 241 int i, nr_sets; 242 243 /* 244 * If there aren't any vectors left after applying the pre/post 245 * vectors don't bother with assigning affinity. 246 */ 247 if (nvecs == affd->pre_vectors + affd->post_vectors) 248 return NULL; 249 250 node_to_cpumask = alloc_node_to_cpumask(); 251 if (!node_to_cpumask) 252 return NULL; 253 254 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL); 255 if (!masks) 256 goto outnodemsk; 257 258 /* 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); 261 /* 262 * Spread on present CPUs starting from affd->pre_vectors. If we 263 * have multiple sets, build each sets affinity mask separately. 264 */ 265 nr_sets = affd->nr_sets; 266 if (!nr_sets) 267 nr_sets = 1; 268 269 for (i = 0, usedvecs = 0; i < nr_sets; i++) { 270 int this_vecs = affd->sets ? affd->sets[i] : affvecs; 271 int ret; 272 273 ret = irq_build_affinity_masks(affd, curvec, this_vecs, 274 curvec, node_to_cpumask, masks); 275 if (ret) { 276 kfree(masks); 277 masks = NULL; 278 goto outnodemsk; 279 } 280 curvec += this_vecs; 281 usedvecs += this_vecs; 282 } 283 284 /* Fill out vectors at the end that don't need affinity */ 285 if (usedvecs >= affvecs) 286 curvec = affd->pre_vectors + affvecs; 287 else 288 curvec = affd->pre_vectors + usedvecs; 289 for (; curvec < nvecs; curvec++) 290 cpumask_copy(&masks[curvec].mask, irq_default_affinity); 291 292 /* Mark the managed interrupts */ 293 for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++) 294 masks[i].is_managed = 1; 295 296 outnodemsk: 297 free_node_to_cpumask(node_to_cpumask); 298 return masks; 299 } 300 301 /** 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 306 */ 307 int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd) 308 { 309 int resv = affd->pre_vectors + affd->post_vectors; 310 int vecs = maxvec - resv; 311 int set_vecs; 312 313 if (resv > minvec) 314 return 0; 315 316 if (affd->nr_sets) { 317 int i; 318 319 for (i = 0, set_vecs = 0; i < affd->nr_sets; i++) 320 set_vecs += affd->sets[i]; 321 } else { 322 get_online_cpus(); 323 set_vecs = cpumask_weight(cpu_possible_mask); 324 put_online_cpus(); 325 } 326 327 return resv + min(set_vecs, vecs); 328 } 329