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 unsigned 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 unsigned int startvec, 99 unsigned int numvecs, 100 unsigned int firstvec, 101 cpumask_var_t *node_to_cpumask, 102 const struct cpumask *cpu_mask, 103 struct cpumask *nmsk, 104 struct irq_affinity_desc *masks) 105 { 106 unsigned int n, nodes, cpus_per_vec, extra_vecs, done = 0; 107 unsigned int last_affv = firstvec + numvecs; 108 unsigned int curvec = startvec; 109 nodemask_t nodemsk = NODE_MASK_NONE; 110 111 if (!cpumask_weight(cpu_mask)) 112 return 0; 113 114 nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk); 115 116 /* 117 * If the number of nodes in the mask is greater than or equal the 118 * number of vectors we just spread the vectors across the nodes. 119 */ 120 if (numvecs <= nodes) { 121 for_each_node_mask(n, nodemsk) { 122 cpumask_or(&masks[curvec].mask, &masks[curvec].mask, 123 node_to_cpumask[n]); 124 if (++curvec == last_affv) 125 curvec = firstvec; 126 } 127 return numvecs; 128 } 129 130 for_each_node_mask(n, nodemsk) { 131 unsigned 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 return done; 167 } 168 169 /* 170 * build affinity in two stages: 171 * 1) spread present CPU on these vectors 172 * 2) spread other possible CPUs on these vectors 173 */ 174 static int irq_build_affinity_masks(const struct irq_affinity *affd, 175 unsigned int startvec, unsigned int numvecs, 176 unsigned int firstvec, 177 struct irq_affinity_desc *masks) 178 { 179 unsigned int curvec = startvec, nr_present, nr_others; 180 cpumask_var_t *node_to_cpumask; 181 cpumask_var_t nmsk, npresmsk; 182 int ret = -ENOMEM; 183 184 if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL)) 185 return ret; 186 187 if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL)) 188 goto fail_nmsk; 189 190 node_to_cpumask = alloc_node_to_cpumask(); 191 if (!node_to_cpumask) 192 goto fail_npresmsk; 193 194 ret = 0; 195 /* Stabilize the cpumasks */ 196 get_online_cpus(); 197 build_node_to_cpumask(node_to_cpumask); 198 199 /* Spread on present CPUs starting from affd->pre_vectors */ 200 nr_present = __irq_build_affinity_masks(affd, curvec, numvecs, 201 firstvec, node_to_cpumask, 202 cpu_present_mask, nmsk, masks); 203 204 /* 205 * Spread on non present CPUs starting from the next vector to be 206 * handled. If the spreading of present CPUs already exhausted the 207 * vector space, assign the non present CPUs to the already spread 208 * out vectors. 209 */ 210 if (nr_present >= numvecs) 211 curvec = firstvec; 212 else 213 curvec = firstvec + nr_present; 214 cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask); 215 nr_others = __irq_build_affinity_masks(affd, curvec, numvecs, 216 firstvec, node_to_cpumask, 217 npresmsk, nmsk, masks); 218 put_online_cpus(); 219 220 if (nr_present < numvecs) 221 WARN_ON(nr_present + nr_others < numvecs); 222 223 free_node_to_cpumask(node_to_cpumask); 224 225 fail_npresmsk: 226 free_cpumask_var(npresmsk); 227 228 fail_nmsk: 229 free_cpumask_var(nmsk); 230 return ret; 231 } 232 233 static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs) 234 { 235 affd->nr_sets = 1; 236 affd->set_size[0] = affvecs; 237 } 238 239 /** 240 * irq_create_affinity_masks - Create affinity masks for multiqueue spreading 241 * @nvecs: The total number of vectors 242 * @affd: Description of the affinity requirements 243 * 244 * Returns the irq_affinity_desc pointer or NULL if allocation failed. 245 */ 246 struct irq_affinity_desc * 247 irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd) 248 { 249 unsigned int affvecs, curvec, usedvecs, i; 250 struct irq_affinity_desc *masks = NULL; 251 252 /* 253 * Determine the number of vectors which need interrupt affinities 254 * assigned. If the pre/post request exhausts the available vectors 255 * then nothing to do here except for invoking the calc_sets() 256 * callback so the device driver can adjust to the situation. If there 257 * is only a single vector, then managing the queue is pointless as 258 * well. 259 */ 260 if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors) 261 affvecs = nvecs - affd->pre_vectors - affd->post_vectors; 262 else 263 affvecs = 0; 264 265 /* 266 * Simple invocations do not provide a calc_sets() callback. Install 267 * the generic one. 268 */ 269 if (!affd->calc_sets) 270 affd->calc_sets = default_calc_sets; 271 272 /* Recalculate the sets */ 273 affd->calc_sets(affd, affvecs); 274 275 if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS)) 276 return NULL; 277 278 /* Nothing to assign? */ 279 if (!affvecs) 280 return NULL; 281 282 masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL); 283 if (!masks) 284 return NULL; 285 286 /* Fill out vectors at the beginning that don't need affinity */ 287 for (curvec = 0; curvec < affd->pre_vectors; curvec++) 288 cpumask_copy(&masks[curvec].mask, irq_default_affinity); 289 290 /* 291 * Spread on present CPUs starting from affd->pre_vectors. If we 292 * have multiple sets, build each sets affinity mask separately. 293 */ 294 for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) { 295 unsigned int this_vecs = affd->set_size[i]; 296 int ret; 297 298 ret = irq_build_affinity_masks(affd, curvec, this_vecs, 299 curvec, masks); 300 if (ret) { 301 kfree(masks); 302 return NULL; 303 } 304 curvec += this_vecs; 305 usedvecs += this_vecs; 306 } 307 308 /* Fill out vectors at the end that don't need affinity */ 309 if (usedvecs >= affvecs) 310 curvec = affd->pre_vectors + affvecs; 311 else 312 curvec = affd->pre_vectors + usedvecs; 313 for (; curvec < nvecs; curvec++) 314 cpumask_copy(&masks[curvec].mask, irq_default_affinity); 315 316 /* Mark the managed interrupts */ 317 for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++) 318 masks[i].is_managed = 1; 319 320 return masks; 321 } 322 323 /** 324 * irq_calc_affinity_vectors - Calculate the optimal number of vectors 325 * @minvec: The minimum number of vectors available 326 * @maxvec: The maximum number of vectors available 327 * @affd: Description of the affinity requirements 328 */ 329 unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec, 330 const struct irq_affinity *affd) 331 { 332 unsigned int resv = affd->pre_vectors + affd->post_vectors; 333 unsigned int set_vecs; 334 335 if (resv > minvec) 336 return 0; 337 338 if (affd->calc_sets) { 339 set_vecs = maxvec - resv; 340 } else { 341 get_online_cpus(); 342 set_vecs = cpumask_weight(cpu_possible_mask); 343 put_online_cpus(); 344 } 345 346 return resv + min(set_vecs, maxvec - resv); 347 } 348