| 1 | /* |
| 2 | * tracing_map - lock-free map for tracing |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com> |
| 15 | * |
| 16 | * tracing_map implementation inspired by lock-free map algorithms |
| 17 | * originated by Dr. Cliff Click: |
| 18 | * |
| 19 | * http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable |
| 20 | * http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf |
| 21 | */ |
| 22 | |
| 23 | #include <linux/vmalloc.h> |
| 24 | #include <linux/jhash.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/sort.h> |
| 27 | |
| 28 | #include "tracing_map.h" |
| 29 | #include "trace.h" |
| 30 | |
| 31 | /* |
| 32 | * NOTE: For a detailed description of the data structures used by |
| 33 | * these functions (such as tracing_map_elt) please see the overview |
| 34 | * of tracing_map data structures at the beginning of tracing_map.h. |
| 35 | */ |
| 36 | |
| 37 | /** |
| 38 | * tracing_map_update_sum - Add a value to a tracing_map_elt's sum field |
| 39 | * @elt: The tracing_map_elt |
| 40 | * @i: The index of the given sum associated with the tracing_map_elt |
| 41 | * @n: The value to add to the sum |
| 42 | * |
| 43 | * Add n to sum i associated with the specified tracing_map_elt |
| 44 | * instance. The index i is the index returned by the call to |
| 45 | * tracing_map_add_sum_field() when the tracing map was set up. |
| 46 | */ |
| 47 | void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n) |
| 48 | { |
| 49 | atomic64_add(n, &elt->fields[i].sum); |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * tracing_map_read_sum - Return the value of a tracing_map_elt's sum field |
| 54 | * @elt: The tracing_map_elt |
| 55 | * @i: The index of the given sum associated with the tracing_map_elt |
| 56 | * |
| 57 | * Retrieve the value of the sum i associated with the specified |
| 58 | * tracing_map_elt instance. The index i is the index returned by the |
| 59 | * call to tracing_map_add_sum_field() when the tracing map was set |
| 60 | * up. |
| 61 | * |
| 62 | * Return: The sum associated with field i for elt. |
| 63 | */ |
| 64 | u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i) |
| 65 | { |
| 66 | return (u64)atomic64_read(&elt->fields[i].sum); |
| 67 | } |
| 68 | |
| 69 | int tracing_map_cmp_string(void *val_a, void *val_b) |
| 70 | { |
| 71 | char *a = val_a; |
| 72 | char *b = val_b; |
| 73 | |
| 74 | return strcmp(a, b); |
| 75 | } |
| 76 | |
| 77 | int tracing_map_cmp_none(void *val_a, void *val_b) |
| 78 | { |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | static int tracing_map_cmp_atomic64(void *val_a, void *val_b) |
| 83 | { |
| 84 | u64 a = atomic64_read((atomic64_t *)val_a); |
| 85 | u64 b = atomic64_read((atomic64_t *)val_b); |
| 86 | |
| 87 | return (a > b) ? 1 : ((a < b) ? -1 : 0); |
| 88 | } |
| 89 | |
| 90 | #define DEFINE_TRACING_MAP_CMP_FN(type) \ |
| 91 | static int tracing_map_cmp_##type(void *val_a, void *val_b) \ |
| 92 | { \ |
| 93 | type a = *(type *)val_a; \ |
| 94 | type b = *(type *)val_b; \ |
| 95 | \ |
| 96 | return (a > b) ? 1 : ((a < b) ? -1 : 0); \ |
| 97 | } |
| 98 | |
| 99 | DEFINE_TRACING_MAP_CMP_FN(s64); |
| 100 | DEFINE_TRACING_MAP_CMP_FN(u64); |
| 101 | DEFINE_TRACING_MAP_CMP_FN(s32); |
| 102 | DEFINE_TRACING_MAP_CMP_FN(u32); |
| 103 | DEFINE_TRACING_MAP_CMP_FN(s16); |
| 104 | DEFINE_TRACING_MAP_CMP_FN(u16); |
| 105 | DEFINE_TRACING_MAP_CMP_FN(s8); |
| 106 | DEFINE_TRACING_MAP_CMP_FN(u8); |
| 107 | |
| 108 | tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size, |
| 109 | int field_is_signed) |
| 110 | { |
| 111 | tracing_map_cmp_fn_t fn = tracing_map_cmp_none; |
| 112 | |
| 113 | switch (field_size) { |
| 114 | case 8: |
| 115 | if (field_is_signed) |
| 116 | fn = tracing_map_cmp_s64; |
| 117 | else |
| 118 | fn = tracing_map_cmp_u64; |
| 119 | break; |
| 120 | case 4: |
| 121 | if (field_is_signed) |
| 122 | fn = tracing_map_cmp_s32; |
| 123 | else |
| 124 | fn = tracing_map_cmp_u32; |
| 125 | break; |
| 126 | case 2: |
| 127 | if (field_is_signed) |
| 128 | fn = tracing_map_cmp_s16; |
| 129 | else |
| 130 | fn = tracing_map_cmp_u16; |
| 131 | break; |
| 132 | case 1: |
| 133 | if (field_is_signed) |
| 134 | fn = tracing_map_cmp_s8; |
| 135 | else |
| 136 | fn = tracing_map_cmp_u8; |
| 137 | break; |
| 138 | } |
| 139 | |
| 140 | return fn; |
| 141 | } |
| 142 | |
| 143 | static int tracing_map_add_field(struct tracing_map *map, |
| 144 | tracing_map_cmp_fn_t cmp_fn) |
| 145 | { |
| 146 | int ret = -EINVAL; |
| 147 | |
| 148 | if (map->n_fields < TRACING_MAP_FIELDS_MAX) { |
| 149 | ret = map->n_fields; |
| 150 | map->fields[map->n_fields++].cmp_fn = cmp_fn; |
| 151 | } |
| 152 | |
| 153 | return ret; |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * tracing_map_add_sum_field - Add a field describing a tracing_map sum |
| 158 | * @map: The tracing_map |
| 159 | * |
| 160 | * Add a sum field to the key and return the index identifying it in |
| 161 | * the map and associated tracing_map_elts. This is the index used |
| 162 | * for instance to update a sum for a particular tracing_map_elt using |
| 163 | * tracing_map_update_sum() or reading it via tracing_map_read_sum(). |
| 164 | * |
| 165 | * Return: The index identifying the field in the map and associated |
| 166 | * tracing_map_elts, or -EINVAL on error. |
| 167 | */ |
| 168 | int tracing_map_add_sum_field(struct tracing_map *map) |
| 169 | { |
| 170 | return tracing_map_add_field(map, tracing_map_cmp_atomic64); |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | * tracing_map_add_key_field - Add a field describing a tracing_map key |
| 175 | * @map: The tracing_map |
| 176 | * @offset: The offset within the key |
| 177 | * @cmp_fn: The comparison function that will be used to sort on the key |
| 178 | * |
| 179 | * Let the map know there is a key and that if it's used as a sort key |
| 180 | * to use cmp_fn. |
| 181 | * |
| 182 | * A key can be a subset of a compound key; for that purpose, the |
| 183 | * offset param is used to describe where within the the compound key |
| 184 | * the key referenced by this key field resides. |
| 185 | * |
| 186 | * Return: The index identifying the field in the map and associated |
| 187 | * tracing_map_elts, or -EINVAL on error. |
| 188 | */ |
| 189 | int tracing_map_add_key_field(struct tracing_map *map, |
| 190 | unsigned int offset, |
| 191 | tracing_map_cmp_fn_t cmp_fn) |
| 192 | |
| 193 | { |
| 194 | int idx = tracing_map_add_field(map, cmp_fn); |
| 195 | |
| 196 | if (idx < 0) |
| 197 | return idx; |
| 198 | |
| 199 | map->fields[idx].offset = offset; |
| 200 | |
| 201 | map->key_idx[map->n_keys++] = idx; |
| 202 | |
| 203 | return idx; |
| 204 | } |
| 205 | |
| 206 | void tracing_map_array_clear(struct tracing_map_array *a) |
| 207 | { |
| 208 | unsigned int i; |
| 209 | |
| 210 | if (!a->pages) |
| 211 | return; |
| 212 | |
| 213 | for (i = 0; i < a->n_pages; i++) |
| 214 | memset(a->pages[i], 0, PAGE_SIZE); |
| 215 | } |
| 216 | |
| 217 | void tracing_map_array_free(struct tracing_map_array *a) |
| 218 | { |
| 219 | unsigned int i; |
| 220 | |
| 221 | if (!a) |
| 222 | return; |
| 223 | |
| 224 | if (!a->pages) { |
| 225 | kfree(a); |
| 226 | return; |
| 227 | } |
| 228 | |
| 229 | for (i = 0; i < a->n_pages; i++) { |
| 230 | if (!a->pages[i]) |
| 231 | break; |
| 232 | free_page((unsigned long)a->pages[i]); |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts, |
| 237 | unsigned int entry_size) |
| 238 | { |
| 239 | struct tracing_map_array *a; |
| 240 | unsigned int i; |
| 241 | |
| 242 | a = kzalloc(sizeof(*a), GFP_KERNEL); |
| 243 | if (!a) |
| 244 | return NULL; |
| 245 | |
| 246 | a->entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1); |
| 247 | a->entries_per_page = PAGE_SIZE / (1 << a->entry_size_shift); |
| 248 | a->n_pages = n_elts / a->entries_per_page; |
| 249 | if (!a->n_pages) |
| 250 | a->n_pages = 1; |
| 251 | a->entry_shift = fls(a->entries_per_page) - 1; |
| 252 | a->entry_mask = (1 << a->entry_shift) - 1; |
| 253 | |
| 254 | a->pages = kcalloc(a->n_pages, sizeof(void *), GFP_KERNEL); |
| 255 | if (!a->pages) |
| 256 | goto free; |
| 257 | |
| 258 | for (i = 0; i < a->n_pages; i++) { |
| 259 | a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL); |
| 260 | if (!a->pages[i]) |
| 261 | goto free; |
| 262 | } |
| 263 | out: |
| 264 | return a; |
| 265 | free: |
| 266 | tracing_map_array_free(a); |
| 267 | a = NULL; |
| 268 | |
| 269 | goto out; |
| 270 | } |
| 271 | |
| 272 | static void tracing_map_elt_clear(struct tracing_map_elt *elt) |
| 273 | { |
| 274 | unsigned i; |
| 275 | |
| 276 | for (i = 0; i < elt->map->n_fields; i++) |
| 277 | if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64) |
| 278 | atomic64_set(&elt->fields[i].sum, 0); |
| 279 | |
| 280 | if (elt->map->ops && elt->map->ops->elt_clear) |
| 281 | elt->map->ops->elt_clear(elt); |
| 282 | } |
| 283 | |
| 284 | static void tracing_map_elt_init_fields(struct tracing_map_elt *elt) |
| 285 | { |
| 286 | unsigned int i; |
| 287 | |
| 288 | tracing_map_elt_clear(elt); |
| 289 | |
| 290 | for (i = 0; i < elt->map->n_fields; i++) { |
| 291 | elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn; |
| 292 | |
| 293 | if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64) |
| 294 | elt->fields[i].offset = elt->map->fields[i].offset; |
| 295 | } |
| 296 | } |
| 297 | |
| 298 | static void tracing_map_elt_free(struct tracing_map_elt *elt) |
| 299 | { |
| 300 | if (!elt) |
| 301 | return; |
| 302 | |
| 303 | if (elt->map->ops && elt->map->ops->elt_free) |
| 304 | elt->map->ops->elt_free(elt); |
| 305 | kfree(elt->fields); |
| 306 | kfree(elt->key); |
| 307 | kfree(elt); |
| 308 | } |
| 309 | |
| 310 | static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map) |
| 311 | { |
| 312 | struct tracing_map_elt *elt; |
| 313 | int err = 0; |
| 314 | |
| 315 | elt = kzalloc(sizeof(*elt), GFP_KERNEL); |
| 316 | if (!elt) |
| 317 | return ERR_PTR(-ENOMEM); |
| 318 | |
| 319 | elt->map = map; |
| 320 | |
| 321 | elt->key = kzalloc(map->key_size, GFP_KERNEL); |
| 322 | if (!elt->key) { |
| 323 | err = -ENOMEM; |
| 324 | goto free; |
| 325 | } |
| 326 | |
| 327 | elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL); |
| 328 | if (!elt->fields) { |
| 329 | err = -ENOMEM; |
| 330 | goto free; |
| 331 | } |
| 332 | |
| 333 | tracing_map_elt_init_fields(elt); |
| 334 | |
| 335 | if (map->ops && map->ops->elt_alloc) { |
| 336 | err = map->ops->elt_alloc(elt); |
| 337 | if (err) |
| 338 | goto free; |
| 339 | } |
| 340 | return elt; |
| 341 | free: |
| 342 | tracing_map_elt_free(elt); |
| 343 | |
| 344 | return ERR_PTR(err); |
| 345 | } |
| 346 | |
| 347 | static struct tracing_map_elt *get_free_elt(struct tracing_map *map) |
| 348 | { |
| 349 | struct tracing_map_elt *elt = NULL; |
| 350 | int idx; |
| 351 | |
| 352 | idx = atomic_inc_return(&map->next_elt); |
| 353 | if (idx < map->max_elts) { |
| 354 | elt = *(TRACING_MAP_ELT(map->elts, idx)); |
| 355 | if (map->ops && map->ops->elt_init) |
| 356 | map->ops->elt_init(elt); |
| 357 | } |
| 358 | |
| 359 | return elt; |
| 360 | } |
| 361 | |
| 362 | static void tracing_map_free_elts(struct tracing_map *map) |
| 363 | { |
| 364 | unsigned int i; |
| 365 | |
| 366 | if (!map->elts) |
| 367 | return; |
| 368 | |
| 369 | for (i = 0; i < map->max_elts; i++) { |
| 370 | tracing_map_elt_free(*(TRACING_MAP_ELT(map->elts, i))); |
| 371 | *(TRACING_MAP_ELT(map->elts, i)) = NULL; |
| 372 | } |
| 373 | |
| 374 | tracing_map_array_free(map->elts); |
| 375 | map->elts = NULL; |
| 376 | } |
| 377 | |
| 378 | static int tracing_map_alloc_elts(struct tracing_map *map) |
| 379 | { |
| 380 | unsigned int i; |
| 381 | |
| 382 | map->elts = tracing_map_array_alloc(map->max_elts, |
| 383 | sizeof(struct tracing_map_elt *)); |
| 384 | if (!map->elts) |
| 385 | return -ENOMEM; |
| 386 | |
| 387 | for (i = 0; i < map->max_elts; i++) { |
| 388 | *(TRACING_MAP_ELT(map->elts, i)) = tracing_map_elt_alloc(map); |
| 389 | if (IS_ERR(*(TRACING_MAP_ELT(map->elts, i)))) { |
| 390 | *(TRACING_MAP_ELT(map->elts, i)) = NULL; |
| 391 | tracing_map_free_elts(map); |
| 392 | |
| 393 | return -ENOMEM; |
| 394 | } |
| 395 | } |
| 396 | |
| 397 | return 0; |
| 398 | } |
| 399 | |
| 400 | static inline bool keys_match(void *key, void *test_key, unsigned key_size) |
| 401 | { |
| 402 | bool match = true; |
| 403 | |
| 404 | if (memcmp(key, test_key, key_size)) |
| 405 | match = false; |
| 406 | |
| 407 | return match; |
| 408 | } |
| 409 | |
| 410 | static inline struct tracing_map_elt * |
| 411 | __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) |
| 412 | { |
| 413 | u32 idx, key_hash, test_key; |
| 414 | struct tracing_map_entry *entry; |
| 415 | |
| 416 | key_hash = jhash(key, map->key_size, 0); |
| 417 | if (key_hash == 0) |
| 418 | key_hash = 1; |
| 419 | idx = key_hash >> (32 - (map->map_bits + 1)); |
| 420 | |
| 421 | while (1) { |
| 422 | idx &= (map->map_size - 1); |
| 423 | entry = TRACING_MAP_ENTRY(map->map, idx); |
| 424 | test_key = entry->key; |
| 425 | |
| 426 | if (test_key && test_key == key_hash && entry->val && |
| 427 | keys_match(key, entry->val->key, map->key_size)) { |
| 428 | atomic64_inc(&map->hits); |
| 429 | return entry->val; |
| 430 | } |
| 431 | |
| 432 | if (!test_key) { |
| 433 | if (lookup_only) |
| 434 | break; |
| 435 | |
| 436 | if (!cmpxchg(&entry->key, 0, key_hash)) { |
| 437 | struct tracing_map_elt *elt; |
| 438 | |
| 439 | elt = get_free_elt(map); |
| 440 | if (!elt) { |
| 441 | atomic64_inc(&map->drops); |
| 442 | entry->key = 0; |
| 443 | break; |
| 444 | } |
| 445 | |
| 446 | memcpy(elt->key, key, map->key_size); |
| 447 | entry->val = elt; |
| 448 | atomic64_inc(&map->hits); |
| 449 | |
| 450 | return entry->val; |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | idx++; |
| 455 | } |
| 456 | |
| 457 | return NULL; |
| 458 | } |
| 459 | |
| 460 | /** |
| 461 | * tracing_map_insert - Insert key and/or retrieve val from a tracing_map |
| 462 | * @map: The tracing_map to insert into |
| 463 | * @key: The key to insert |
| 464 | * |
| 465 | * Inserts a key into a tracing_map and creates and returns a new |
| 466 | * tracing_map_elt for it, or if the key has already been inserted by |
| 467 | * a previous call, returns the tracing_map_elt already associated |
| 468 | * with it. When the map was created, the number of elements to be |
| 469 | * allocated for the map was specified (internally maintained as |
| 470 | * 'max_elts' in struct tracing_map), and that number of |
| 471 | * tracing_map_elts was created by tracing_map_init(). This is the |
| 472 | * pre-allocated pool of tracing_map_elts that tracing_map_insert() |
| 473 | * will allocate from when adding new keys. Once that pool is |
| 474 | * exhausted, tracing_map_insert() is useless and will return NULL to |
| 475 | * signal that state. There are two user-visible tracing_map |
| 476 | * variables, 'hits' and 'drops', which are updated by this function. |
| 477 | * Every time an element is either successfully inserted or retrieved, |
| 478 | * the 'hits' value is incrememented. Every time an element insertion |
| 479 | * fails, the 'drops' value is incremented. |
| 480 | * |
| 481 | * This is a lock-free tracing map insertion function implementing a |
| 482 | * modified form of Cliff Click's basic insertion algorithm. It |
| 483 | * requires the table size be a power of two. To prevent any |
| 484 | * possibility of an infinite loop we always make the internal table |
| 485 | * size double the size of the requested table size (max_elts * 2). |
| 486 | * Likewise, we never reuse a slot or resize or delete elements - when |
| 487 | * we've reached max_elts entries, we simply return NULL once we've |
| 488 | * run out of entries. Readers can at any point in time traverse the |
| 489 | * tracing map and safely access the key/val pairs. |
| 490 | * |
| 491 | * Return: the tracing_map_elt pointer val associated with the key. |
| 492 | * If this was a newly inserted key, the val will be a newly allocated |
| 493 | * and associated tracing_map_elt pointer val. If the key wasn't |
| 494 | * found and the pool of tracing_map_elts has been exhausted, NULL is |
| 495 | * returned and no further insertions will succeed. |
| 496 | */ |
| 497 | struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key) |
| 498 | { |
| 499 | return __tracing_map_insert(map, key, false); |
| 500 | } |
| 501 | |
| 502 | /** |
| 503 | * tracing_map_lookup - Retrieve val from a tracing_map |
| 504 | * @map: The tracing_map to perform the lookup on |
| 505 | * @key: The key to look up |
| 506 | * |
| 507 | * Looks up key in tracing_map and if found returns the matching |
| 508 | * tracing_map_elt. This is a lock-free lookup; see |
| 509 | * tracing_map_insert() for details on tracing_map and how it works. |
| 510 | * Every time an element is retrieved, the 'hits' value is |
| 511 | * incrememented. There is one user-visible tracing_map variable, |
| 512 | * 'hits', which is updated by this function. Every time an element |
| 513 | * is successfully retrieved, the 'hits' value is incrememented. The |
| 514 | * 'drops' value is never updated by this function. |
| 515 | * |
| 516 | * Return: the tracing_map_elt pointer val associated with the key. |
| 517 | * If the key wasn't found, NULL is returned. |
| 518 | */ |
| 519 | struct tracing_map_elt *tracing_map_lookup(struct tracing_map *map, void *key) |
| 520 | { |
| 521 | return __tracing_map_insert(map, key, true); |
| 522 | } |
| 523 | |
| 524 | /** |
| 525 | * tracing_map_destroy - Destroy a tracing_map |
| 526 | * @map: The tracing_map to destroy |
| 527 | * |
| 528 | * Frees a tracing_map along with its associated array of |
| 529 | * tracing_map_elts. |
| 530 | * |
| 531 | * Callers should make sure there are no readers or writers actively |
| 532 | * reading or inserting into the map before calling this. |
| 533 | */ |
| 534 | void tracing_map_destroy(struct tracing_map *map) |
| 535 | { |
| 536 | if (!map) |
| 537 | return; |
| 538 | |
| 539 | tracing_map_free_elts(map); |
| 540 | |
| 541 | tracing_map_array_free(map->map); |
| 542 | kfree(map); |
| 543 | } |
| 544 | |
| 545 | /** |
| 546 | * tracing_map_clear - Clear a tracing_map |
| 547 | * @map: The tracing_map to clear |
| 548 | * |
| 549 | * Resets the tracing map to a cleared or initial state. The |
| 550 | * tracing_map_elts are all cleared, and the array of struct |
| 551 | * tracing_map_entry is reset to an initialized state. |
| 552 | * |
| 553 | * Callers should make sure there are no writers actively inserting |
| 554 | * into the map before calling this. |
| 555 | */ |
| 556 | void tracing_map_clear(struct tracing_map *map) |
| 557 | { |
| 558 | unsigned int i; |
| 559 | |
| 560 | atomic_set(&map->next_elt, -1); |
| 561 | atomic64_set(&map->hits, 0); |
| 562 | atomic64_set(&map->drops, 0); |
| 563 | |
| 564 | tracing_map_array_clear(map->map); |
| 565 | |
| 566 | for (i = 0; i < map->max_elts; i++) |
| 567 | tracing_map_elt_clear(*(TRACING_MAP_ELT(map->elts, i))); |
| 568 | } |
| 569 | |
| 570 | static void set_sort_key(struct tracing_map *map, |
| 571 | struct tracing_map_sort_key *sort_key) |
| 572 | { |
| 573 | map->sort_key = *sort_key; |
| 574 | } |
| 575 | |
| 576 | /** |
| 577 | * tracing_map_create - Create a lock-free map and element pool |
| 578 | * @map_bits: The size of the map (2 ** map_bits) |
| 579 | * @key_size: The size of the key for the map in bytes |
| 580 | * @ops: Optional client-defined tracing_map_ops instance |
| 581 | * @private_data: Client data associated with the map |
| 582 | * |
| 583 | * Creates and sets up a map to contain 2 ** map_bits number of |
| 584 | * elements (internally maintained as 'max_elts' in struct |
| 585 | * tracing_map). Before using, map fields should be added to the map |
| 586 | * with tracing_map_add_sum_field() and tracing_map_add_key_field(). |
| 587 | * tracing_map_init() should then be called to allocate the array of |
| 588 | * tracing_map_elts, in order to avoid allocating anything in the map |
| 589 | * insertion path. The user-specified map size reflects the maximum |
| 590 | * number of elements that can be contained in the table requested by |
| 591 | * the user - internally we double that in order to keep the table |
| 592 | * sparse and keep collisions manageable. |
| 593 | * |
| 594 | * A tracing_map is a special-purpose map designed to aggregate or |
| 595 | * 'sum' one or more values associated with a specific object of type |
| 596 | * tracing_map_elt, which is attached by the map to a given key. |
| 597 | * |
| 598 | * tracing_map_create() sets up the map itself, and provides |
| 599 | * operations for inserting tracing_map_elts, but doesn't allocate the |
| 600 | * tracing_map_elts themselves, or provide a means for describing the |
| 601 | * keys or sums associated with the tracing_map_elts. All |
| 602 | * tracing_map_elts for a given map have the same set of sums and |
| 603 | * keys, which are defined by the client using the functions |
| 604 | * tracing_map_add_key_field() and tracing_map_add_sum_field(). Once |
| 605 | * the fields are defined, the pool of elements allocated for the map |
| 606 | * can be created, which occurs when the client code calls |
| 607 | * tracing_map_init(). |
| 608 | * |
| 609 | * When tracing_map_init() returns, tracing_map_elt elements can be |
| 610 | * inserted into the map using tracing_map_insert(). When called, |
| 611 | * tracing_map_insert() grabs a free tracing_map_elt from the pool, or |
| 612 | * finds an existing match in the map and in either case returns it. |
| 613 | * The client can then use tracing_map_update_sum() and |
| 614 | * tracing_map_read_sum() to update or read a given sum field for the |
| 615 | * tracing_map_elt. |
| 616 | * |
| 617 | * The client can at any point retrieve and traverse the current set |
| 618 | * of inserted tracing_map_elts in a tracing_map, via |
| 619 | * tracing_map_sort_entries(). Sorting can be done on any field, |
| 620 | * including keys. |
| 621 | * |
| 622 | * See tracing_map.h for a description of tracing_map_ops. |
| 623 | * |
| 624 | * Return: the tracing_map pointer if successful, ERR_PTR if not. |
| 625 | */ |
| 626 | struct tracing_map *tracing_map_create(unsigned int map_bits, |
| 627 | unsigned int key_size, |
| 628 | const struct tracing_map_ops *ops, |
| 629 | void *private_data) |
| 630 | { |
| 631 | struct tracing_map *map; |
| 632 | unsigned int i; |
| 633 | |
| 634 | if (map_bits < TRACING_MAP_BITS_MIN || |
| 635 | map_bits > TRACING_MAP_BITS_MAX) |
| 636 | return ERR_PTR(-EINVAL); |
| 637 | |
| 638 | map = kzalloc(sizeof(*map), GFP_KERNEL); |
| 639 | if (!map) |
| 640 | return ERR_PTR(-ENOMEM); |
| 641 | |
| 642 | map->map_bits = map_bits; |
| 643 | map->max_elts = (1 << map_bits); |
| 644 | atomic_set(&map->next_elt, -1); |
| 645 | |
| 646 | map->map_size = (1 << (map_bits + 1)); |
| 647 | map->ops = ops; |
| 648 | |
| 649 | map->private_data = private_data; |
| 650 | |
| 651 | map->map = tracing_map_array_alloc(map->map_size, |
| 652 | sizeof(struct tracing_map_entry)); |
| 653 | if (!map->map) |
| 654 | goto free; |
| 655 | |
| 656 | map->key_size = key_size; |
| 657 | for (i = 0; i < TRACING_MAP_KEYS_MAX; i++) |
| 658 | map->key_idx[i] = -1; |
| 659 | out: |
| 660 | return map; |
| 661 | free: |
| 662 | tracing_map_destroy(map); |
| 663 | map = ERR_PTR(-ENOMEM); |
| 664 | |
| 665 | goto out; |
| 666 | } |
| 667 | |
| 668 | /** |
| 669 | * tracing_map_init - Allocate and clear a map's tracing_map_elts |
| 670 | * @map: The tracing_map to initialize |
| 671 | * |
| 672 | * Allocates a clears a pool of tracing_map_elts equal to the |
| 673 | * user-specified size of 2 ** map_bits (internally maintained as |
| 674 | * 'max_elts' in struct tracing_map). Before using, the map fields |
| 675 | * should be added to the map with tracing_map_add_sum_field() and |
| 676 | * tracing_map_add_key_field(). tracing_map_init() should then be |
| 677 | * called to allocate the array of tracing_map_elts, in order to avoid |
| 678 | * allocating anything in the map insertion path. The user-specified |
| 679 | * map size reflects the max number of elements requested by the user |
| 680 | * - internally we double that in order to keep the table sparse and |
| 681 | * keep collisions manageable. |
| 682 | * |
| 683 | * See tracing_map.h for a description of tracing_map_ops. |
| 684 | * |
| 685 | * Return: the tracing_map pointer if successful, ERR_PTR if not. |
| 686 | */ |
| 687 | int tracing_map_init(struct tracing_map *map) |
| 688 | { |
| 689 | int err; |
| 690 | |
| 691 | if (map->n_fields < 2) |
| 692 | return -EINVAL; /* need at least 1 key and 1 val */ |
| 693 | |
| 694 | err = tracing_map_alloc_elts(map); |
| 695 | if (err) |
| 696 | return err; |
| 697 | |
| 698 | tracing_map_clear(map); |
| 699 | |
| 700 | return err; |
| 701 | } |
| 702 | |
| 703 | static int cmp_entries_dup(const struct tracing_map_sort_entry **a, |
| 704 | const struct tracing_map_sort_entry **b) |
| 705 | { |
| 706 | int ret = 0; |
| 707 | |
| 708 | if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size)) |
| 709 | ret = 1; |
| 710 | |
| 711 | return ret; |
| 712 | } |
| 713 | |
| 714 | static int cmp_entries_sum(const struct tracing_map_sort_entry **a, |
| 715 | const struct tracing_map_sort_entry **b) |
| 716 | { |
| 717 | const struct tracing_map_elt *elt_a, *elt_b; |
| 718 | struct tracing_map_sort_key *sort_key; |
| 719 | struct tracing_map_field *field; |
| 720 | tracing_map_cmp_fn_t cmp_fn; |
| 721 | void *val_a, *val_b; |
| 722 | int ret = 0; |
| 723 | |
| 724 | elt_a = (*a)->elt; |
| 725 | elt_b = (*b)->elt; |
| 726 | |
| 727 | sort_key = &elt_a->map->sort_key; |
| 728 | |
| 729 | field = &elt_a->fields[sort_key->field_idx]; |
| 730 | cmp_fn = field->cmp_fn; |
| 731 | |
| 732 | val_a = &elt_a->fields[sort_key->field_idx].sum; |
| 733 | val_b = &elt_b->fields[sort_key->field_idx].sum; |
| 734 | |
| 735 | ret = cmp_fn(val_a, val_b); |
| 736 | if (sort_key->descending) |
| 737 | ret = -ret; |
| 738 | |
| 739 | return ret; |
| 740 | } |
| 741 | |
| 742 | static int cmp_entries_key(const struct tracing_map_sort_entry **a, |
| 743 | const struct tracing_map_sort_entry **b) |
| 744 | { |
| 745 | const struct tracing_map_elt *elt_a, *elt_b; |
| 746 | struct tracing_map_sort_key *sort_key; |
| 747 | struct tracing_map_field *field; |
| 748 | tracing_map_cmp_fn_t cmp_fn; |
| 749 | void *val_a, *val_b; |
| 750 | int ret = 0; |
| 751 | |
| 752 | elt_a = (*a)->elt; |
| 753 | elt_b = (*b)->elt; |
| 754 | |
| 755 | sort_key = &elt_a->map->sort_key; |
| 756 | |
| 757 | field = &elt_a->fields[sort_key->field_idx]; |
| 758 | |
| 759 | cmp_fn = field->cmp_fn; |
| 760 | |
| 761 | val_a = elt_a->key + field->offset; |
| 762 | val_b = elt_b->key + field->offset; |
| 763 | |
| 764 | ret = cmp_fn(val_a, val_b); |
| 765 | if (sort_key->descending) |
| 766 | ret = -ret; |
| 767 | |
| 768 | return ret; |
| 769 | } |
| 770 | |
| 771 | static void destroy_sort_entry(struct tracing_map_sort_entry *entry) |
| 772 | { |
| 773 | if (!entry) |
| 774 | return; |
| 775 | |
| 776 | if (entry->elt_copied) |
| 777 | tracing_map_elt_free(entry->elt); |
| 778 | |
| 779 | kfree(entry); |
| 780 | } |
| 781 | |
| 782 | /** |
| 783 | * tracing_map_destroy_sort_entries - Destroy an array of sort entries |
| 784 | * @entries: The entries to destroy |
| 785 | * @n_entries: The number of entries in the array |
| 786 | * |
| 787 | * Destroy the elements returned by a tracing_map_sort_entries() call. |
| 788 | */ |
| 789 | void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries, |
| 790 | unsigned int n_entries) |
| 791 | { |
| 792 | unsigned int i; |
| 793 | |
| 794 | for (i = 0; i < n_entries; i++) |
| 795 | destroy_sort_entry(entries[i]); |
| 796 | |
| 797 | vfree(entries); |
| 798 | } |
| 799 | |
| 800 | static struct tracing_map_sort_entry * |
| 801 | create_sort_entry(void *key, struct tracing_map_elt *elt) |
| 802 | { |
| 803 | struct tracing_map_sort_entry *sort_entry; |
| 804 | |
| 805 | sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL); |
| 806 | if (!sort_entry) |
| 807 | return NULL; |
| 808 | |
| 809 | sort_entry->key = key; |
| 810 | sort_entry->elt = elt; |
| 811 | |
| 812 | return sort_entry; |
| 813 | } |
| 814 | |
| 815 | static struct tracing_map_elt *copy_elt(struct tracing_map_elt *elt) |
| 816 | { |
| 817 | struct tracing_map_elt *dup_elt; |
| 818 | unsigned int i; |
| 819 | |
| 820 | dup_elt = tracing_map_elt_alloc(elt->map); |
| 821 | if (IS_ERR(dup_elt)) |
| 822 | return NULL; |
| 823 | |
| 824 | if (elt->map->ops && elt->map->ops->elt_copy) |
| 825 | elt->map->ops->elt_copy(dup_elt, elt); |
| 826 | |
| 827 | dup_elt->private_data = elt->private_data; |
| 828 | memcpy(dup_elt->key, elt->key, elt->map->key_size); |
| 829 | |
| 830 | for (i = 0; i < elt->map->n_fields; i++) { |
| 831 | atomic64_set(&dup_elt->fields[i].sum, |
| 832 | atomic64_read(&elt->fields[i].sum)); |
| 833 | dup_elt->fields[i].cmp_fn = elt->fields[i].cmp_fn; |
| 834 | } |
| 835 | |
| 836 | return dup_elt; |
| 837 | } |
| 838 | |
| 839 | static int merge_dup(struct tracing_map_sort_entry **sort_entries, |
| 840 | unsigned int target, unsigned int dup) |
| 841 | { |
| 842 | struct tracing_map_elt *target_elt, *elt; |
| 843 | bool first_dup = (target - dup) == 1; |
| 844 | int i; |
| 845 | |
| 846 | if (first_dup) { |
| 847 | elt = sort_entries[target]->elt; |
| 848 | target_elt = copy_elt(elt); |
| 849 | if (!target_elt) |
| 850 | return -ENOMEM; |
| 851 | sort_entries[target]->elt = target_elt; |
| 852 | sort_entries[target]->elt_copied = true; |
| 853 | } else |
| 854 | target_elt = sort_entries[target]->elt; |
| 855 | |
| 856 | elt = sort_entries[dup]->elt; |
| 857 | |
| 858 | for (i = 0; i < elt->map->n_fields; i++) |
| 859 | atomic64_add(atomic64_read(&elt->fields[i].sum), |
| 860 | &target_elt->fields[i].sum); |
| 861 | |
| 862 | sort_entries[dup]->dup = true; |
| 863 | |
| 864 | return 0; |
| 865 | } |
| 866 | |
| 867 | static int merge_dups(struct tracing_map_sort_entry **sort_entries, |
| 868 | int n_entries, unsigned int key_size) |
| 869 | { |
| 870 | unsigned int dups = 0, total_dups = 0; |
| 871 | int err, i, j; |
| 872 | void *key; |
| 873 | |
| 874 | if (n_entries < 2) |
| 875 | return total_dups; |
| 876 | |
| 877 | sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *), |
| 878 | (int (*)(const void *, const void *))cmp_entries_dup, NULL); |
| 879 | |
| 880 | key = sort_entries[0]->key; |
| 881 | for (i = 1; i < n_entries; i++) { |
| 882 | if (!memcmp(sort_entries[i]->key, key, key_size)) { |
| 883 | dups++; total_dups++; |
| 884 | err = merge_dup(sort_entries, i - dups, i); |
| 885 | if (err) |
| 886 | return err; |
| 887 | continue; |
| 888 | } |
| 889 | key = sort_entries[i]->key; |
| 890 | dups = 0; |
| 891 | } |
| 892 | |
| 893 | if (!total_dups) |
| 894 | return total_dups; |
| 895 | |
| 896 | for (i = 0, j = 0; i < n_entries; i++) { |
| 897 | if (!sort_entries[i]->dup) { |
| 898 | sort_entries[j] = sort_entries[i]; |
| 899 | if (j++ != i) |
| 900 | sort_entries[i] = NULL; |
| 901 | } else { |
| 902 | destroy_sort_entry(sort_entries[i]); |
| 903 | sort_entries[i] = NULL; |
| 904 | } |
| 905 | } |
| 906 | |
| 907 | return total_dups; |
| 908 | } |
| 909 | |
| 910 | static bool is_key(struct tracing_map *map, unsigned int field_idx) |
| 911 | { |
| 912 | unsigned int i; |
| 913 | |
| 914 | for (i = 0; i < map->n_keys; i++) |
| 915 | if (map->key_idx[i] == field_idx) |
| 916 | return true; |
| 917 | return false; |
| 918 | } |
| 919 | |
| 920 | static void sort_secondary(struct tracing_map *map, |
| 921 | const struct tracing_map_sort_entry **entries, |
| 922 | unsigned int n_entries, |
| 923 | struct tracing_map_sort_key *primary_key, |
| 924 | struct tracing_map_sort_key *secondary_key) |
| 925 | { |
| 926 | int (*primary_fn)(const struct tracing_map_sort_entry **, |
| 927 | const struct tracing_map_sort_entry **); |
| 928 | int (*secondary_fn)(const struct tracing_map_sort_entry **, |
| 929 | const struct tracing_map_sort_entry **); |
| 930 | unsigned i, start = 0, n_sub = 1; |
| 931 | |
| 932 | if (is_key(map, primary_key->field_idx)) |
| 933 | primary_fn = cmp_entries_key; |
| 934 | else |
| 935 | primary_fn = cmp_entries_sum; |
| 936 | |
| 937 | if (is_key(map, secondary_key->field_idx)) |
| 938 | secondary_fn = cmp_entries_key; |
| 939 | else |
| 940 | secondary_fn = cmp_entries_sum; |
| 941 | |
| 942 | for (i = 0; i < n_entries - 1; i++) { |
| 943 | const struct tracing_map_sort_entry **a = &entries[i]; |
| 944 | const struct tracing_map_sort_entry **b = &entries[i + 1]; |
| 945 | |
| 946 | if (primary_fn(a, b) == 0) { |
| 947 | n_sub++; |
| 948 | if (i < n_entries - 2) |
| 949 | continue; |
| 950 | } |
| 951 | |
| 952 | if (n_sub < 2) { |
| 953 | start = i + 1; |
| 954 | n_sub = 1; |
| 955 | continue; |
| 956 | } |
| 957 | |
| 958 | set_sort_key(map, secondary_key); |
| 959 | sort(&entries[start], n_sub, |
| 960 | sizeof(struct tracing_map_sort_entry *), |
| 961 | (int (*)(const void *, const void *))secondary_fn, NULL); |
| 962 | set_sort_key(map, primary_key); |
| 963 | |
| 964 | start = i + 1; |
| 965 | n_sub = 1; |
| 966 | } |
| 967 | } |
| 968 | |
| 969 | /** |
| 970 | * tracing_map_sort_entries - Sort the current set of tracing_map_elts in a map |
| 971 | * @map: The tracing_map |
| 972 | * @sort_key: The sort key to use for sorting |
| 973 | * @sort_entries: outval: pointer to allocated and sorted array of entries |
| 974 | * |
| 975 | * tracing_map_sort_entries() sorts the current set of entries in the |
| 976 | * map and returns the list of tracing_map_sort_entries containing |
| 977 | * them to the client in the sort_entries param. The client can |
| 978 | * access the struct tracing_map_elt element of interest directly as |
| 979 | * the 'elt' field of a returned struct tracing_map_sort_entry object. |
| 980 | * |
| 981 | * The sort_key has only two fields: idx and descending. 'idx' refers |
| 982 | * to the index of the field added via tracing_map_add_sum_field() or |
| 983 | * tracing_map_add_key_field() when the tracing_map was initialized. |
| 984 | * 'descending' is a flag that if set reverses the sort order, which |
| 985 | * by default is ascending. |
| 986 | * |
| 987 | * The client should not hold on to the returned array but should use |
| 988 | * it and call tracing_map_destroy_sort_entries() when done. |
| 989 | * |
| 990 | * Return: the number of sort_entries in the struct tracing_map_sort_entry |
| 991 | * array, negative on error |
| 992 | */ |
| 993 | int tracing_map_sort_entries(struct tracing_map *map, |
| 994 | struct tracing_map_sort_key *sort_keys, |
| 995 | unsigned int n_sort_keys, |
| 996 | struct tracing_map_sort_entry ***sort_entries) |
| 997 | { |
| 998 | int (*cmp_entries_fn)(const struct tracing_map_sort_entry **, |
| 999 | const struct tracing_map_sort_entry **); |
| 1000 | struct tracing_map_sort_entry *sort_entry, **entries; |
| 1001 | int i, n_entries, ret; |
| 1002 | |
| 1003 | entries = vmalloc(map->max_elts * sizeof(sort_entry)); |
| 1004 | if (!entries) |
| 1005 | return -ENOMEM; |
| 1006 | |
| 1007 | for (i = 0, n_entries = 0; i < map->map_size; i++) { |
| 1008 | struct tracing_map_entry *entry; |
| 1009 | |
| 1010 | entry = TRACING_MAP_ENTRY(map->map, i); |
| 1011 | |
| 1012 | if (!entry->key || !entry->val) |
| 1013 | continue; |
| 1014 | |
| 1015 | entries[n_entries] = create_sort_entry(entry->val->key, |
| 1016 | entry->val); |
| 1017 | if (!entries[n_entries++]) { |
| 1018 | ret = -ENOMEM; |
| 1019 | goto free; |
| 1020 | } |
| 1021 | } |
| 1022 | |
| 1023 | if (n_entries == 0) { |
| 1024 | ret = 0; |
| 1025 | goto free; |
| 1026 | } |
| 1027 | |
| 1028 | if (n_entries == 1) { |
| 1029 | *sort_entries = entries; |
| 1030 | return 1; |
| 1031 | } |
| 1032 | |
| 1033 | ret = merge_dups(entries, n_entries, map->key_size); |
| 1034 | if (ret < 0) |
| 1035 | goto free; |
| 1036 | n_entries -= ret; |
| 1037 | |
| 1038 | if (is_key(map, sort_keys[0].field_idx)) |
| 1039 | cmp_entries_fn = cmp_entries_key; |
| 1040 | else |
| 1041 | cmp_entries_fn = cmp_entries_sum; |
| 1042 | |
| 1043 | set_sort_key(map, &sort_keys[0]); |
| 1044 | |
| 1045 | sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *), |
| 1046 | (int (*)(const void *, const void *))cmp_entries_fn, NULL); |
| 1047 | |
| 1048 | if (n_sort_keys > 1) |
| 1049 | sort_secondary(map, |
| 1050 | (const struct tracing_map_sort_entry **)entries, |
| 1051 | n_entries, |
| 1052 | &sort_keys[0], |
| 1053 | &sort_keys[1]); |
| 1054 | |
| 1055 | *sort_entries = entries; |
| 1056 | |
| 1057 | return n_entries; |
| 1058 | free: |
| 1059 | tracing_map_destroy_sort_entries(entries, n_entries); |
| 1060 | |
| 1061 | return ret; |
| 1062 | } |