| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Data Access Monitor |
| 4 | * |
| 5 | * Author: SeongJae Park <sjpark@amazon.de> |
| 6 | */ |
| 7 | |
| 8 | #define pr_fmt(fmt) "damon: " fmt |
| 9 | |
| 10 | #include <linux/damon.h> |
| 11 | #include <linux/delay.h> |
| 12 | #include <linux/kthread.h> |
| 13 | #include <linux/mm.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/string.h> |
| 16 | |
| 17 | #define CREATE_TRACE_POINTS |
| 18 | #include <trace/events/damon.h> |
| 19 | |
| 20 | #ifdef CONFIG_DAMON_KUNIT_TEST |
| 21 | #undef DAMON_MIN_REGION |
| 22 | #define DAMON_MIN_REGION 1 |
| 23 | #endif |
| 24 | |
| 25 | static DEFINE_MUTEX(damon_lock); |
| 26 | static int nr_running_ctxs; |
| 27 | static bool running_exclusive_ctxs; |
| 28 | |
| 29 | static DEFINE_MUTEX(damon_ops_lock); |
| 30 | static struct damon_operations damon_registered_ops[NR_DAMON_OPS]; |
| 31 | |
| 32 | static struct kmem_cache *damon_region_cache __ro_after_init; |
| 33 | |
| 34 | /* Should be called under damon_ops_lock with id smaller than NR_DAMON_OPS */ |
| 35 | static bool __damon_is_registered_ops(enum damon_ops_id id) |
| 36 | { |
| 37 | struct damon_operations empty_ops = {}; |
| 38 | |
| 39 | if (!memcmp(&empty_ops, &damon_registered_ops[id], sizeof(empty_ops))) |
| 40 | return false; |
| 41 | return true; |
| 42 | } |
| 43 | |
| 44 | /** |
| 45 | * damon_is_registered_ops() - Check if a given damon_operations is registered. |
| 46 | * @id: Id of the damon_operations to check if registered. |
| 47 | * |
| 48 | * Return: true if the ops is set, false otherwise. |
| 49 | */ |
| 50 | bool damon_is_registered_ops(enum damon_ops_id id) |
| 51 | { |
| 52 | bool registered; |
| 53 | |
| 54 | if (id >= NR_DAMON_OPS) |
| 55 | return false; |
| 56 | mutex_lock(&damon_ops_lock); |
| 57 | registered = __damon_is_registered_ops(id); |
| 58 | mutex_unlock(&damon_ops_lock); |
| 59 | return registered; |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * damon_register_ops() - Register a monitoring operations set to DAMON. |
| 64 | * @ops: monitoring operations set to register. |
| 65 | * |
| 66 | * This function registers a monitoring operations set of valid &struct |
| 67 | * damon_operations->id so that others can find and use them later. |
| 68 | * |
| 69 | * Return: 0 on success, negative error code otherwise. |
| 70 | */ |
| 71 | int damon_register_ops(struct damon_operations *ops) |
| 72 | { |
| 73 | int err = 0; |
| 74 | |
| 75 | if (ops->id >= NR_DAMON_OPS) |
| 76 | return -EINVAL; |
| 77 | mutex_lock(&damon_ops_lock); |
| 78 | /* Fail for already registered ops */ |
| 79 | if (__damon_is_registered_ops(ops->id)) { |
| 80 | err = -EINVAL; |
| 81 | goto out; |
| 82 | } |
| 83 | damon_registered_ops[ops->id] = *ops; |
| 84 | out: |
| 85 | mutex_unlock(&damon_ops_lock); |
| 86 | return err; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * damon_select_ops() - Select a monitoring operations to use with the context. |
| 91 | * @ctx: monitoring context to use the operations. |
| 92 | * @id: id of the registered monitoring operations to select. |
| 93 | * |
| 94 | * This function finds registered monitoring operations set of @id and make |
| 95 | * @ctx to use it. |
| 96 | * |
| 97 | * Return: 0 on success, negative error code otherwise. |
| 98 | */ |
| 99 | int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id) |
| 100 | { |
| 101 | int err = 0; |
| 102 | |
| 103 | if (id >= NR_DAMON_OPS) |
| 104 | return -EINVAL; |
| 105 | |
| 106 | mutex_lock(&damon_ops_lock); |
| 107 | if (!__damon_is_registered_ops(id)) |
| 108 | err = -EINVAL; |
| 109 | else |
| 110 | ctx->ops = damon_registered_ops[id]; |
| 111 | mutex_unlock(&damon_ops_lock); |
| 112 | return err; |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * Construct a damon_region struct |
| 117 | * |
| 118 | * Returns the pointer to the new struct if success, or NULL otherwise |
| 119 | */ |
| 120 | struct damon_region *damon_new_region(unsigned long start, unsigned long end) |
| 121 | { |
| 122 | struct damon_region *region; |
| 123 | |
| 124 | region = kmem_cache_alloc(damon_region_cache, GFP_KERNEL); |
| 125 | if (!region) |
| 126 | return NULL; |
| 127 | |
| 128 | region->ar.start = start; |
| 129 | region->ar.end = end; |
| 130 | region->nr_accesses = 0; |
| 131 | INIT_LIST_HEAD(®ion->list); |
| 132 | |
| 133 | region->age = 0; |
| 134 | region->last_nr_accesses = 0; |
| 135 | |
| 136 | return region; |
| 137 | } |
| 138 | |
| 139 | void damon_add_region(struct damon_region *r, struct damon_target *t) |
| 140 | { |
| 141 | list_add_tail(&r->list, &t->regions_list); |
| 142 | t->nr_regions++; |
| 143 | } |
| 144 | |
| 145 | static void damon_del_region(struct damon_region *r, struct damon_target *t) |
| 146 | { |
| 147 | list_del(&r->list); |
| 148 | t->nr_regions--; |
| 149 | } |
| 150 | |
| 151 | static void damon_free_region(struct damon_region *r) |
| 152 | { |
| 153 | kmem_cache_free(damon_region_cache, r); |
| 154 | } |
| 155 | |
| 156 | void damon_destroy_region(struct damon_region *r, struct damon_target *t) |
| 157 | { |
| 158 | damon_del_region(r, t); |
| 159 | damon_free_region(r); |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * Check whether a region is intersecting an address range |
| 164 | * |
| 165 | * Returns true if it is. |
| 166 | */ |
| 167 | static bool damon_intersect(struct damon_region *r, |
| 168 | struct damon_addr_range *re) |
| 169 | { |
| 170 | return !(r->ar.end <= re->start || re->end <= r->ar.start); |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Fill holes in regions with new regions. |
| 175 | */ |
| 176 | static int damon_fill_regions_holes(struct damon_region *first, |
| 177 | struct damon_region *last, struct damon_target *t) |
| 178 | { |
| 179 | struct damon_region *r = first; |
| 180 | |
| 181 | damon_for_each_region_from(r, t) { |
| 182 | struct damon_region *next, *newr; |
| 183 | |
| 184 | if (r == last) |
| 185 | break; |
| 186 | next = damon_next_region(r); |
| 187 | if (r->ar.end != next->ar.start) { |
| 188 | newr = damon_new_region(r->ar.end, next->ar.start); |
| 189 | if (!newr) |
| 190 | return -ENOMEM; |
| 191 | damon_insert_region(newr, r, next, t); |
| 192 | } |
| 193 | } |
| 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * damon_set_regions() - Set regions of a target for given address ranges. |
| 199 | * @t: the given target. |
| 200 | * @ranges: array of new monitoring target ranges. |
| 201 | * @nr_ranges: length of @ranges. |
| 202 | * |
| 203 | * This function adds new regions to, or modify existing regions of a |
| 204 | * monitoring target to fit in specific ranges. |
| 205 | * |
| 206 | * Return: 0 if success, or negative error code otherwise. |
| 207 | */ |
| 208 | int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges, |
| 209 | unsigned int nr_ranges) |
| 210 | { |
| 211 | struct damon_region *r, *next; |
| 212 | unsigned int i; |
| 213 | int err; |
| 214 | |
| 215 | /* Remove regions which are not in the new ranges */ |
| 216 | damon_for_each_region_safe(r, next, t) { |
| 217 | for (i = 0; i < nr_ranges; i++) { |
| 218 | if (damon_intersect(r, &ranges[i])) |
| 219 | break; |
| 220 | } |
| 221 | if (i == nr_ranges) |
| 222 | damon_destroy_region(r, t); |
| 223 | } |
| 224 | |
| 225 | r = damon_first_region(t); |
| 226 | /* Add new regions or resize existing regions to fit in the ranges */ |
| 227 | for (i = 0; i < nr_ranges; i++) { |
| 228 | struct damon_region *first = NULL, *last, *newr; |
| 229 | struct damon_addr_range *range; |
| 230 | |
| 231 | range = &ranges[i]; |
| 232 | /* Get the first/last regions intersecting with the range */ |
| 233 | damon_for_each_region_from(r, t) { |
| 234 | if (damon_intersect(r, range)) { |
| 235 | if (!first) |
| 236 | first = r; |
| 237 | last = r; |
| 238 | } |
| 239 | if (r->ar.start >= range->end) |
| 240 | break; |
| 241 | } |
| 242 | if (!first) { |
| 243 | /* no region intersects with this range */ |
| 244 | newr = damon_new_region( |
| 245 | ALIGN_DOWN(range->start, |
| 246 | DAMON_MIN_REGION), |
| 247 | ALIGN(range->end, DAMON_MIN_REGION)); |
| 248 | if (!newr) |
| 249 | return -ENOMEM; |
| 250 | damon_insert_region(newr, damon_prev_region(r), r, t); |
| 251 | } else { |
| 252 | /* resize intersecting regions to fit in this range */ |
| 253 | first->ar.start = ALIGN_DOWN(range->start, |
| 254 | DAMON_MIN_REGION); |
| 255 | last->ar.end = ALIGN(range->end, DAMON_MIN_REGION); |
| 256 | |
| 257 | /* fill possible holes in the range */ |
| 258 | err = damon_fill_regions_holes(first, last, t); |
| 259 | if (err) |
| 260 | return err; |
| 261 | } |
| 262 | } |
| 263 | return 0; |
| 264 | } |
| 265 | |
| 266 | struct damos_filter *damos_new_filter(enum damos_filter_type type, |
| 267 | bool matching) |
| 268 | { |
| 269 | struct damos_filter *filter; |
| 270 | |
| 271 | filter = kmalloc(sizeof(*filter), GFP_KERNEL); |
| 272 | if (!filter) |
| 273 | return NULL; |
| 274 | filter->type = type; |
| 275 | filter->matching = matching; |
| 276 | INIT_LIST_HEAD(&filter->list); |
| 277 | return filter; |
| 278 | } |
| 279 | |
| 280 | void damos_add_filter(struct damos *s, struct damos_filter *f) |
| 281 | { |
| 282 | list_add_tail(&f->list, &s->filters); |
| 283 | } |
| 284 | |
| 285 | static void damos_del_filter(struct damos_filter *f) |
| 286 | { |
| 287 | list_del(&f->list); |
| 288 | } |
| 289 | |
| 290 | static void damos_free_filter(struct damos_filter *f) |
| 291 | { |
| 292 | kfree(f); |
| 293 | } |
| 294 | |
| 295 | void damos_destroy_filter(struct damos_filter *f) |
| 296 | { |
| 297 | damos_del_filter(f); |
| 298 | damos_free_filter(f); |
| 299 | } |
| 300 | |
| 301 | /* initialize private fields of damos_quota and return the pointer */ |
| 302 | static struct damos_quota *damos_quota_init_priv(struct damos_quota *quota) |
| 303 | { |
| 304 | quota->total_charged_sz = 0; |
| 305 | quota->total_charged_ns = 0; |
| 306 | quota->esz = 0; |
| 307 | quota->charged_sz = 0; |
| 308 | quota->charged_from = 0; |
| 309 | quota->charge_target_from = NULL; |
| 310 | quota->charge_addr_from = 0; |
| 311 | return quota; |
| 312 | } |
| 313 | |
| 314 | struct damos *damon_new_scheme(struct damos_access_pattern *pattern, |
| 315 | enum damos_action action, struct damos_quota *quota, |
| 316 | struct damos_watermarks *wmarks) |
| 317 | { |
| 318 | struct damos *scheme; |
| 319 | |
| 320 | scheme = kmalloc(sizeof(*scheme), GFP_KERNEL); |
| 321 | if (!scheme) |
| 322 | return NULL; |
| 323 | scheme->pattern = *pattern; |
| 324 | scheme->action = action; |
| 325 | INIT_LIST_HEAD(&scheme->filters); |
| 326 | scheme->stat = (struct damos_stat){}; |
| 327 | INIT_LIST_HEAD(&scheme->list); |
| 328 | |
| 329 | scheme->quota = *(damos_quota_init_priv(quota)); |
| 330 | |
| 331 | scheme->wmarks = *wmarks; |
| 332 | scheme->wmarks.activated = true; |
| 333 | |
| 334 | return scheme; |
| 335 | } |
| 336 | |
| 337 | void damon_add_scheme(struct damon_ctx *ctx, struct damos *s) |
| 338 | { |
| 339 | list_add_tail(&s->list, &ctx->schemes); |
| 340 | } |
| 341 | |
| 342 | static void damon_del_scheme(struct damos *s) |
| 343 | { |
| 344 | list_del(&s->list); |
| 345 | } |
| 346 | |
| 347 | static void damon_free_scheme(struct damos *s) |
| 348 | { |
| 349 | kfree(s); |
| 350 | } |
| 351 | |
| 352 | void damon_destroy_scheme(struct damos *s) |
| 353 | { |
| 354 | struct damos_filter *f, *next; |
| 355 | |
| 356 | damos_for_each_filter_safe(f, next, s) |
| 357 | damos_destroy_filter(f); |
| 358 | damon_del_scheme(s); |
| 359 | damon_free_scheme(s); |
| 360 | } |
| 361 | |
| 362 | /* |
| 363 | * Construct a damon_target struct |
| 364 | * |
| 365 | * Returns the pointer to the new struct if success, or NULL otherwise |
| 366 | */ |
| 367 | struct damon_target *damon_new_target(void) |
| 368 | { |
| 369 | struct damon_target *t; |
| 370 | |
| 371 | t = kmalloc(sizeof(*t), GFP_KERNEL); |
| 372 | if (!t) |
| 373 | return NULL; |
| 374 | |
| 375 | t->pid = NULL; |
| 376 | t->nr_regions = 0; |
| 377 | INIT_LIST_HEAD(&t->regions_list); |
| 378 | INIT_LIST_HEAD(&t->list); |
| 379 | |
| 380 | return t; |
| 381 | } |
| 382 | |
| 383 | void damon_add_target(struct damon_ctx *ctx, struct damon_target *t) |
| 384 | { |
| 385 | list_add_tail(&t->list, &ctx->adaptive_targets); |
| 386 | } |
| 387 | |
| 388 | bool damon_targets_empty(struct damon_ctx *ctx) |
| 389 | { |
| 390 | return list_empty(&ctx->adaptive_targets); |
| 391 | } |
| 392 | |
| 393 | static void damon_del_target(struct damon_target *t) |
| 394 | { |
| 395 | list_del(&t->list); |
| 396 | } |
| 397 | |
| 398 | void damon_free_target(struct damon_target *t) |
| 399 | { |
| 400 | struct damon_region *r, *next; |
| 401 | |
| 402 | damon_for_each_region_safe(r, next, t) |
| 403 | damon_free_region(r); |
| 404 | kfree(t); |
| 405 | } |
| 406 | |
| 407 | void damon_destroy_target(struct damon_target *t) |
| 408 | { |
| 409 | damon_del_target(t); |
| 410 | damon_free_target(t); |
| 411 | } |
| 412 | |
| 413 | unsigned int damon_nr_regions(struct damon_target *t) |
| 414 | { |
| 415 | return t->nr_regions; |
| 416 | } |
| 417 | |
| 418 | struct damon_ctx *damon_new_ctx(void) |
| 419 | { |
| 420 | struct damon_ctx *ctx; |
| 421 | |
| 422 | ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); |
| 423 | if (!ctx) |
| 424 | return NULL; |
| 425 | |
| 426 | ctx->attrs.sample_interval = 5 * 1000; |
| 427 | ctx->attrs.aggr_interval = 100 * 1000; |
| 428 | ctx->attrs.ops_update_interval = 60 * 1000 * 1000; |
| 429 | |
| 430 | ktime_get_coarse_ts64(&ctx->last_aggregation); |
| 431 | ctx->last_ops_update = ctx->last_aggregation; |
| 432 | |
| 433 | mutex_init(&ctx->kdamond_lock); |
| 434 | |
| 435 | ctx->attrs.min_nr_regions = 10; |
| 436 | ctx->attrs.max_nr_regions = 1000; |
| 437 | |
| 438 | INIT_LIST_HEAD(&ctx->adaptive_targets); |
| 439 | INIT_LIST_HEAD(&ctx->schemes); |
| 440 | |
| 441 | return ctx; |
| 442 | } |
| 443 | |
| 444 | static void damon_destroy_targets(struct damon_ctx *ctx) |
| 445 | { |
| 446 | struct damon_target *t, *next_t; |
| 447 | |
| 448 | if (ctx->ops.cleanup) { |
| 449 | ctx->ops.cleanup(ctx); |
| 450 | return; |
| 451 | } |
| 452 | |
| 453 | damon_for_each_target_safe(t, next_t, ctx) |
| 454 | damon_destroy_target(t); |
| 455 | } |
| 456 | |
| 457 | void damon_destroy_ctx(struct damon_ctx *ctx) |
| 458 | { |
| 459 | struct damos *s, *next_s; |
| 460 | |
| 461 | damon_destroy_targets(ctx); |
| 462 | |
| 463 | damon_for_each_scheme_safe(s, next_s, ctx) |
| 464 | damon_destroy_scheme(s); |
| 465 | |
| 466 | kfree(ctx); |
| 467 | } |
| 468 | |
| 469 | static unsigned int damon_age_for_new_attrs(unsigned int age, |
| 470 | struct damon_attrs *old_attrs, struct damon_attrs *new_attrs) |
| 471 | { |
| 472 | return age * old_attrs->aggr_interval / new_attrs->aggr_interval; |
| 473 | } |
| 474 | |
| 475 | /* convert access ratio in bp (per 10,000) to nr_accesses */ |
| 476 | static unsigned int damon_accesses_bp_to_nr_accesses( |
| 477 | unsigned int accesses_bp, struct damon_attrs *attrs) |
| 478 | { |
| 479 | unsigned int max_nr_accesses = |
| 480 | attrs->aggr_interval / attrs->sample_interval; |
| 481 | |
| 482 | return accesses_bp * max_nr_accesses / 10000; |
| 483 | } |
| 484 | |
| 485 | /* convert nr_accesses to access ratio in bp (per 10,000) */ |
| 486 | static unsigned int damon_nr_accesses_to_accesses_bp( |
| 487 | unsigned int nr_accesses, struct damon_attrs *attrs) |
| 488 | { |
| 489 | unsigned int max_nr_accesses = |
| 490 | attrs->aggr_interval / attrs->sample_interval; |
| 491 | |
| 492 | return nr_accesses * 10000 / max_nr_accesses; |
| 493 | } |
| 494 | |
| 495 | static unsigned int damon_nr_accesses_for_new_attrs(unsigned int nr_accesses, |
| 496 | struct damon_attrs *old_attrs, struct damon_attrs *new_attrs) |
| 497 | { |
| 498 | return damon_accesses_bp_to_nr_accesses( |
| 499 | damon_nr_accesses_to_accesses_bp( |
| 500 | nr_accesses, old_attrs), |
| 501 | new_attrs); |
| 502 | } |
| 503 | |
| 504 | static void damon_update_monitoring_result(struct damon_region *r, |
| 505 | struct damon_attrs *old_attrs, struct damon_attrs *new_attrs) |
| 506 | { |
| 507 | r->nr_accesses = damon_nr_accesses_for_new_attrs(r->nr_accesses, |
| 508 | old_attrs, new_attrs); |
| 509 | r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs); |
| 510 | } |
| 511 | |
| 512 | /* |
| 513 | * region->nr_accesses is the number of sampling intervals in the last |
| 514 | * aggregation interval that access to the region has found, and region->age is |
| 515 | * the number of aggregation intervals that its access pattern has maintained. |
| 516 | * For the reason, the real meaning of the two fields depend on current |
| 517 | * sampling interval and aggregation interval. This function updates |
| 518 | * ->nr_accesses and ->age of given damon_ctx's regions for new damon_attrs. |
| 519 | */ |
| 520 | static void damon_update_monitoring_results(struct damon_ctx *ctx, |
| 521 | struct damon_attrs *new_attrs) |
| 522 | { |
| 523 | struct damon_attrs *old_attrs = &ctx->attrs; |
| 524 | struct damon_target *t; |
| 525 | struct damon_region *r; |
| 526 | |
| 527 | /* if any interval is zero, simply forgive conversion */ |
| 528 | if (!old_attrs->sample_interval || !old_attrs->aggr_interval || |
| 529 | !new_attrs->sample_interval || |
| 530 | !new_attrs->aggr_interval) |
| 531 | return; |
| 532 | |
| 533 | damon_for_each_target(t, ctx) |
| 534 | damon_for_each_region(r, t) |
| 535 | damon_update_monitoring_result( |
| 536 | r, old_attrs, new_attrs); |
| 537 | } |
| 538 | |
| 539 | /** |
| 540 | * damon_set_attrs() - Set attributes for the monitoring. |
| 541 | * @ctx: monitoring context |
| 542 | * @attrs: monitoring attributes |
| 543 | * |
| 544 | * This function should not be called while the kdamond is running. |
| 545 | * Every time interval is in micro-seconds. |
| 546 | * |
| 547 | * Return: 0 on success, negative error code otherwise. |
| 548 | */ |
| 549 | int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs) |
| 550 | { |
| 551 | if (attrs->min_nr_regions < 3) |
| 552 | return -EINVAL; |
| 553 | if (attrs->min_nr_regions > attrs->max_nr_regions) |
| 554 | return -EINVAL; |
| 555 | if (attrs->sample_interval > attrs->aggr_interval) |
| 556 | return -EINVAL; |
| 557 | |
| 558 | damon_update_monitoring_results(ctx, attrs); |
| 559 | ctx->attrs = *attrs; |
| 560 | return 0; |
| 561 | } |
| 562 | |
| 563 | /** |
| 564 | * damon_set_schemes() - Set data access monitoring based operation schemes. |
| 565 | * @ctx: monitoring context |
| 566 | * @schemes: array of the schemes |
| 567 | * @nr_schemes: number of entries in @schemes |
| 568 | * |
| 569 | * This function should not be called while the kdamond of the context is |
| 570 | * running. |
| 571 | */ |
| 572 | void damon_set_schemes(struct damon_ctx *ctx, struct damos **schemes, |
| 573 | ssize_t nr_schemes) |
| 574 | { |
| 575 | struct damos *s, *next; |
| 576 | ssize_t i; |
| 577 | |
| 578 | damon_for_each_scheme_safe(s, next, ctx) |
| 579 | damon_destroy_scheme(s); |
| 580 | for (i = 0; i < nr_schemes; i++) |
| 581 | damon_add_scheme(ctx, schemes[i]); |
| 582 | } |
| 583 | |
| 584 | /** |
| 585 | * damon_nr_running_ctxs() - Return number of currently running contexts. |
| 586 | */ |
| 587 | int damon_nr_running_ctxs(void) |
| 588 | { |
| 589 | int nr_ctxs; |
| 590 | |
| 591 | mutex_lock(&damon_lock); |
| 592 | nr_ctxs = nr_running_ctxs; |
| 593 | mutex_unlock(&damon_lock); |
| 594 | |
| 595 | return nr_ctxs; |
| 596 | } |
| 597 | |
| 598 | /* Returns the size upper limit for each monitoring region */ |
| 599 | static unsigned long damon_region_sz_limit(struct damon_ctx *ctx) |
| 600 | { |
| 601 | struct damon_target *t; |
| 602 | struct damon_region *r; |
| 603 | unsigned long sz = 0; |
| 604 | |
| 605 | damon_for_each_target(t, ctx) { |
| 606 | damon_for_each_region(r, t) |
| 607 | sz += damon_sz_region(r); |
| 608 | } |
| 609 | |
| 610 | if (ctx->attrs.min_nr_regions) |
| 611 | sz /= ctx->attrs.min_nr_regions; |
| 612 | if (sz < DAMON_MIN_REGION) |
| 613 | sz = DAMON_MIN_REGION; |
| 614 | |
| 615 | return sz; |
| 616 | } |
| 617 | |
| 618 | static int kdamond_fn(void *data); |
| 619 | |
| 620 | /* |
| 621 | * __damon_start() - Starts monitoring with given context. |
| 622 | * @ctx: monitoring context |
| 623 | * |
| 624 | * This function should be called while damon_lock is hold. |
| 625 | * |
| 626 | * Return: 0 on success, negative error code otherwise. |
| 627 | */ |
| 628 | static int __damon_start(struct damon_ctx *ctx) |
| 629 | { |
| 630 | int err = -EBUSY; |
| 631 | |
| 632 | mutex_lock(&ctx->kdamond_lock); |
| 633 | if (!ctx->kdamond) { |
| 634 | err = 0; |
| 635 | ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond.%d", |
| 636 | nr_running_ctxs); |
| 637 | if (IS_ERR(ctx->kdamond)) { |
| 638 | err = PTR_ERR(ctx->kdamond); |
| 639 | ctx->kdamond = NULL; |
| 640 | } |
| 641 | } |
| 642 | mutex_unlock(&ctx->kdamond_lock); |
| 643 | |
| 644 | return err; |
| 645 | } |
| 646 | |
| 647 | /** |
| 648 | * damon_start() - Starts the monitorings for a given group of contexts. |
| 649 | * @ctxs: an array of the pointers for contexts to start monitoring |
| 650 | * @nr_ctxs: size of @ctxs |
| 651 | * @exclusive: exclusiveness of this contexts group |
| 652 | * |
| 653 | * This function starts a group of monitoring threads for a group of monitoring |
| 654 | * contexts. One thread per each context is created and run in parallel. The |
| 655 | * caller should handle synchronization between the threads by itself. If |
| 656 | * @exclusive is true and a group of threads that created by other |
| 657 | * 'damon_start()' call is currently running, this function does nothing but |
| 658 | * returns -EBUSY. |
| 659 | * |
| 660 | * Return: 0 on success, negative error code otherwise. |
| 661 | */ |
| 662 | int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive) |
| 663 | { |
| 664 | int i; |
| 665 | int err = 0; |
| 666 | |
| 667 | mutex_lock(&damon_lock); |
| 668 | if ((exclusive && nr_running_ctxs) || |
| 669 | (!exclusive && running_exclusive_ctxs)) { |
| 670 | mutex_unlock(&damon_lock); |
| 671 | return -EBUSY; |
| 672 | } |
| 673 | |
| 674 | for (i = 0; i < nr_ctxs; i++) { |
| 675 | err = __damon_start(ctxs[i]); |
| 676 | if (err) |
| 677 | break; |
| 678 | nr_running_ctxs++; |
| 679 | } |
| 680 | if (exclusive && nr_running_ctxs) |
| 681 | running_exclusive_ctxs = true; |
| 682 | mutex_unlock(&damon_lock); |
| 683 | |
| 684 | return err; |
| 685 | } |
| 686 | |
| 687 | /* |
| 688 | * __damon_stop() - Stops monitoring of a given context. |
| 689 | * @ctx: monitoring context |
| 690 | * |
| 691 | * Return: 0 on success, negative error code otherwise. |
| 692 | */ |
| 693 | static int __damon_stop(struct damon_ctx *ctx) |
| 694 | { |
| 695 | struct task_struct *tsk; |
| 696 | |
| 697 | mutex_lock(&ctx->kdamond_lock); |
| 698 | tsk = ctx->kdamond; |
| 699 | if (tsk) { |
| 700 | get_task_struct(tsk); |
| 701 | mutex_unlock(&ctx->kdamond_lock); |
| 702 | kthread_stop(tsk); |
| 703 | put_task_struct(tsk); |
| 704 | return 0; |
| 705 | } |
| 706 | mutex_unlock(&ctx->kdamond_lock); |
| 707 | |
| 708 | return -EPERM; |
| 709 | } |
| 710 | |
| 711 | /** |
| 712 | * damon_stop() - Stops the monitorings for a given group of contexts. |
| 713 | * @ctxs: an array of the pointers for contexts to stop monitoring |
| 714 | * @nr_ctxs: size of @ctxs |
| 715 | * |
| 716 | * Return: 0 on success, negative error code otherwise. |
| 717 | */ |
| 718 | int damon_stop(struct damon_ctx **ctxs, int nr_ctxs) |
| 719 | { |
| 720 | int i, err = 0; |
| 721 | |
| 722 | for (i = 0; i < nr_ctxs; i++) { |
| 723 | /* nr_running_ctxs is decremented in kdamond_fn */ |
| 724 | err = __damon_stop(ctxs[i]); |
| 725 | if (err) |
| 726 | break; |
| 727 | } |
| 728 | return err; |
| 729 | } |
| 730 | |
| 731 | /* |
| 732 | * damon_check_reset_time_interval() - Check if a time interval is elapsed. |
| 733 | * @baseline: the time to check whether the interval has elapsed since |
| 734 | * @interval: the time interval (microseconds) |
| 735 | * |
| 736 | * See whether the given time interval has passed since the given baseline |
| 737 | * time. If so, it also updates the baseline to current time for next check. |
| 738 | * |
| 739 | * Return: true if the time interval has passed, or false otherwise. |
| 740 | */ |
| 741 | static bool damon_check_reset_time_interval(struct timespec64 *baseline, |
| 742 | unsigned long interval) |
| 743 | { |
| 744 | struct timespec64 now; |
| 745 | |
| 746 | ktime_get_coarse_ts64(&now); |
| 747 | if ((timespec64_to_ns(&now) - timespec64_to_ns(baseline)) < |
| 748 | interval * 1000) |
| 749 | return false; |
| 750 | *baseline = now; |
| 751 | return true; |
| 752 | } |
| 753 | |
| 754 | /* |
| 755 | * Check whether it is time to flush the aggregated information |
| 756 | */ |
| 757 | static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx) |
| 758 | { |
| 759 | return damon_check_reset_time_interval(&ctx->last_aggregation, |
| 760 | ctx->attrs.aggr_interval); |
| 761 | } |
| 762 | |
| 763 | /* |
| 764 | * Reset the aggregated monitoring results ('nr_accesses' of each region). |
| 765 | */ |
| 766 | static void kdamond_reset_aggregated(struct damon_ctx *c) |
| 767 | { |
| 768 | struct damon_target *t; |
| 769 | unsigned int ti = 0; /* target's index */ |
| 770 | |
| 771 | damon_for_each_target(t, c) { |
| 772 | struct damon_region *r; |
| 773 | |
| 774 | damon_for_each_region(r, t) { |
| 775 | trace_damon_aggregated(t, ti, r, damon_nr_regions(t)); |
| 776 | r->last_nr_accesses = r->nr_accesses; |
| 777 | r->nr_accesses = 0; |
| 778 | } |
| 779 | ti++; |
| 780 | } |
| 781 | } |
| 782 | |
| 783 | static void damon_split_region_at(struct damon_target *t, |
| 784 | struct damon_region *r, unsigned long sz_r); |
| 785 | |
| 786 | static bool __damos_valid_target(struct damon_region *r, struct damos *s) |
| 787 | { |
| 788 | unsigned long sz; |
| 789 | |
| 790 | sz = damon_sz_region(r); |
| 791 | return s->pattern.min_sz_region <= sz && |
| 792 | sz <= s->pattern.max_sz_region && |
| 793 | s->pattern.min_nr_accesses <= r->nr_accesses && |
| 794 | r->nr_accesses <= s->pattern.max_nr_accesses && |
| 795 | s->pattern.min_age_region <= r->age && |
| 796 | r->age <= s->pattern.max_age_region; |
| 797 | } |
| 798 | |
| 799 | static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t, |
| 800 | struct damon_region *r, struct damos *s) |
| 801 | { |
| 802 | bool ret = __damos_valid_target(r, s); |
| 803 | |
| 804 | if (!ret || !s->quota.esz || !c->ops.get_scheme_score) |
| 805 | return ret; |
| 806 | |
| 807 | return c->ops.get_scheme_score(c, t, r, s) >= s->quota.min_score; |
| 808 | } |
| 809 | |
| 810 | /* |
| 811 | * damos_skip_charged_region() - Check if the given region or starting part of |
| 812 | * it is already charged for the DAMOS quota. |
| 813 | * @t: The target of the region. |
| 814 | * @rp: The pointer to the region. |
| 815 | * @s: The scheme to be applied. |
| 816 | * |
| 817 | * If a quota of a scheme has exceeded in a quota charge window, the scheme's |
| 818 | * action would applied to only a part of the target access pattern fulfilling |
| 819 | * regions. To avoid applying the scheme action to only already applied |
| 820 | * regions, DAMON skips applying the scheme action to the regions that charged |
| 821 | * in the previous charge window. |
| 822 | * |
| 823 | * This function checks if a given region should be skipped or not for the |
| 824 | * reason. If only the starting part of the region has previously charged, |
| 825 | * this function splits the region into two so that the second one covers the |
| 826 | * area that not charged in the previous charge widnow and saves the second |
| 827 | * region in *rp and returns false, so that the caller can apply DAMON action |
| 828 | * to the second one. |
| 829 | * |
| 830 | * Return: true if the region should be entirely skipped, false otherwise. |
| 831 | */ |
| 832 | static bool damos_skip_charged_region(struct damon_target *t, |
| 833 | struct damon_region **rp, struct damos *s) |
| 834 | { |
| 835 | struct damon_region *r = *rp; |
| 836 | struct damos_quota *quota = &s->quota; |
| 837 | unsigned long sz_to_skip; |
| 838 | |
| 839 | /* Skip previously charged regions */ |
| 840 | if (quota->charge_target_from) { |
| 841 | if (t != quota->charge_target_from) |
| 842 | return true; |
| 843 | if (r == damon_last_region(t)) { |
| 844 | quota->charge_target_from = NULL; |
| 845 | quota->charge_addr_from = 0; |
| 846 | return true; |
| 847 | } |
| 848 | if (quota->charge_addr_from && |
| 849 | r->ar.end <= quota->charge_addr_from) |
| 850 | return true; |
| 851 | |
| 852 | if (quota->charge_addr_from && r->ar.start < |
| 853 | quota->charge_addr_from) { |
| 854 | sz_to_skip = ALIGN_DOWN(quota->charge_addr_from - |
| 855 | r->ar.start, DAMON_MIN_REGION); |
| 856 | if (!sz_to_skip) { |
| 857 | if (damon_sz_region(r) <= DAMON_MIN_REGION) |
| 858 | return true; |
| 859 | sz_to_skip = DAMON_MIN_REGION; |
| 860 | } |
| 861 | damon_split_region_at(t, r, sz_to_skip); |
| 862 | r = damon_next_region(r); |
| 863 | *rp = r; |
| 864 | } |
| 865 | quota->charge_target_from = NULL; |
| 866 | quota->charge_addr_from = 0; |
| 867 | } |
| 868 | return false; |
| 869 | } |
| 870 | |
| 871 | static void damos_update_stat(struct damos *s, |
| 872 | unsigned long sz_tried, unsigned long sz_applied) |
| 873 | { |
| 874 | s->stat.nr_tried++; |
| 875 | s->stat.sz_tried += sz_tried; |
| 876 | if (sz_applied) |
| 877 | s->stat.nr_applied++; |
| 878 | s->stat.sz_applied += sz_applied; |
| 879 | } |
| 880 | |
| 881 | static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t, |
| 882 | struct damon_region *r, struct damos *s) |
| 883 | { |
| 884 | struct damos_quota *quota = &s->quota; |
| 885 | unsigned long sz = damon_sz_region(r); |
| 886 | struct timespec64 begin, end; |
| 887 | unsigned long sz_applied = 0; |
| 888 | int err = 0; |
| 889 | |
| 890 | if (c->ops.apply_scheme) { |
| 891 | if (quota->esz && quota->charged_sz + sz > quota->esz) { |
| 892 | sz = ALIGN_DOWN(quota->esz - quota->charged_sz, |
| 893 | DAMON_MIN_REGION); |
| 894 | if (!sz) |
| 895 | goto update_stat; |
| 896 | damon_split_region_at(t, r, sz); |
| 897 | } |
| 898 | ktime_get_coarse_ts64(&begin); |
| 899 | if (c->callback.before_damos_apply) |
| 900 | err = c->callback.before_damos_apply(c, t, r, s); |
| 901 | if (!err) |
| 902 | sz_applied = c->ops.apply_scheme(c, t, r, s); |
| 903 | ktime_get_coarse_ts64(&end); |
| 904 | quota->total_charged_ns += timespec64_to_ns(&end) - |
| 905 | timespec64_to_ns(&begin); |
| 906 | quota->charged_sz += sz; |
| 907 | if (quota->esz && quota->charged_sz >= quota->esz) { |
| 908 | quota->charge_target_from = t; |
| 909 | quota->charge_addr_from = r->ar.end + 1; |
| 910 | } |
| 911 | } |
| 912 | if (s->action != DAMOS_STAT) |
| 913 | r->age = 0; |
| 914 | |
| 915 | update_stat: |
| 916 | damos_update_stat(s, sz, sz_applied); |
| 917 | } |
| 918 | |
| 919 | static void damon_do_apply_schemes(struct damon_ctx *c, |
| 920 | struct damon_target *t, |
| 921 | struct damon_region *r) |
| 922 | { |
| 923 | struct damos *s; |
| 924 | |
| 925 | damon_for_each_scheme(s, c) { |
| 926 | struct damos_quota *quota = &s->quota; |
| 927 | |
| 928 | if (!s->wmarks.activated) |
| 929 | continue; |
| 930 | |
| 931 | /* Check the quota */ |
| 932 | if (quota->esz && quota->charged_sz >= quota->esz) |
| 933 | continue; |
| 934 | |
| 935 | if (damos_skip_charged_region(t, &r, s)) |
| 936 | continue; |
| 937 | |
| 938 | if (!damos_valid_target(c, t, r, s)) |
| 939 | continue; |
| 940 | |
| 941 | damos_apply_scheme(c, t, r, s); |
| 942 | } |
| 943 | } |
| 944 | |
| 945 | /* Shouldn't be called if quota->ms and quota->sz are zero */ |
| 946 | static void damos_set_effective_quota(struct damos_quota *quota) |
| 947 | { |
| 948 | unsigned long throughput; |
| 949 | unsigned long esz; |
| 950 | |
| 951 | if (!quota->ms) { |
| 952 | quota->esz = quota->sz; |
| 953 | return; |
| 954 | } |
| 955 | |
| 956 | if (quota->total_charged_ns) |
| 957 | throughput = quota->total_charged_sz * 1000000 / |
| 958 | quota->total_charged_ns; |
| 959 | else |
| 960 | throughput = PAGE_SIZE * 1024; |
| 961 | esz = throughput * quota->ms; |
| 962 | |
| 963 | if (quota->sz && quota->sz < esz) |
| 964 | esz = quota->sz; |
| 965 | quota->esz = esz; |
| 966 | } |
| 967 | |
| 968 | static void damos_adjust_quota(struct damon_ctx *c, struct damos *s) |
| 969 | { |
| 970 | struct damos_quota *quota = &s->quota; |
| 971 | struct damon_target *t; |
| 972 | struct damon_region *r; |
| 973 | unsigned long cumulated_sz; |
| 974 | unsigned int score, max_score = 0; |
| 975 | |
| 976 | if (!quota->ms && !quota->sz) |
| 977 | return; |
| 978 | |
| 979 | /* New charge window starts */ |
| 980 | if (time_after_eq(jiffies, quota->charged_from + |
| 981 | msecs_to_jiffies(quota->reset_interval))) { |
| 982 | if (quota->esz && quota->charged_sz >= quota->esz) |
| 983 | s->stat.qt_exceeds++; |
| 984 | quota->total_charged_sz += quota->charged_sz; |
| 985 | quota->charged_from = jiffies; |
| 986 | quota->charged_sz = 0; |
| 987 | damos_set_effective_quota(quota); |
| 988 | } |
| 989 | |
| 990 | if (!c->ops.get_scheme_score) |
| 991 | return; |
| 992 | |
| 993 | /* Fill up the score histogram */ |
| 994 | memset(quota->histogram, 0, sizeof(quota->histogram)); |
| 995 | damon_for_each_target(t, c) { |
| 996 | damon_for_each_region(r, t) { |
| 997 | if (!__damos_valid_target(r, s)) |
| 998 | continue; |
| 999 | score = c->ops.get_scheme_score(c, t, r, s); |
| 1000 | quota->histogram[score] += damon_sz_region(r); |
| 1001 | if (score > max_score) |
| 1002 | max_score = score; |
| 1003 | } |
| 1004 | } |
| 1005 | |
| 1006 | /* Set the min score limit */ |
| 1007 | for (cumulated_sz = 0, score = max_score; ; score--) { |
| 1008 | cumulated_sz += quota->histogram[score]; |
| 1009 | if (cumulated_sz >= quota->esz || !score) |
| 1010 | break; |
| 1011 | } |
| 1012 | quota->min_score = score; |
| 1013 | } |
| 1014 | |
| 1015 | static void kdamond_apply_schemes(struct damon_ctx *c) |
| 1016 | { |
| 1017 | struct damon_target *t; |
| 1018 | struct damon_region *r, *next_r; |
| 1019 | struct damos *s; |
| 1020 | |
| 1021 | damon_for_each_scheme(s, c) { |
| 1022 | if (!s->wmarks.activated) |
| 1023 | continue; |
| 1024 | |
| 1025 | damos_adjust_quota(c, s); |
| 1026 | } |
| 1027 | |
| 1028 | damon_for_each_target(t, c) { |
| 1029 | damon_for_each_region_safe(r, next_r, t) |
| 1030 | damon_do_apply_schemes(c, t, r); |
| 1031 | } |
| 1032 | } |
| 1033 | |
| 1034 | /* |
| 1035 | * Merge two adjacent regions into one region |
| 1036 | */ |
| 1037 | static void damon_merge_two_regions(struct damon_target *t, |
| 1038 | struct damon_region *l, struct damon_region *r) |
| 1039 | { |
| 1040 | unsigned long sz_l = damon_sz_region(l), sz_r = damon_sz_region(r); |
| 1041 | |
| 1042 | l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) / |
| 1043 | (sz_l + sz_r); |
| 1044 | l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r); |
| 1045 | l->ar.end = r->ar.end; |
| 1046 | damon_destroy_region(r, t); |
| 1047 | } |
| 1048 | |
| 1049 | /* |
| 1050 | * Merge adjacent regions having similar access frequencies |
| 1051 | * |
| 1052 | * t target affected by this merge operation |
| 1053 | * thres '->nr_accesses' diff threshold for the merge |
| 1054 | * sz_limit size upper limit of each region |
| 1055 | */ |
| 1056 | static void damon_merge_regions_of(struct damon_target *t, unsigned int thres, |
| 1057 | unsigned long sz_limit) |
| 1058 | { |
| 1059 | struct damon_region *r, *prev = NULL, *next; |
| 1060 | |
| 1061 | damon_for_each_region_safe(r, next, t) { |
| 1062 | if (abs(r->nr_accesses - r->last_nr_accesses) > thres) |
| 1063 | r->age = 0; |
| 1064 | else |
| 1065 | r->age++; |
| 1066 | |
| 1067 | if (prev && prev->ar.end == r->ar.start && |
| 1068 | abs(prev->nr_accesses - r->nr_accesses) <= thres && |
| 1069 | damon_sz_region(prev) + damon_sz_region(r) <= sz_limit) |
| 1070 | damon_merge_two_regions(t, prev, r); |
| 1071 | else |
| 1072 | prev = r; |
| 1073 | } |
| 1074 | } |
| 1075 | |
| 1076 | /* |
| 1077 | * Merge adjacent regions having similar access frequencies |
| 1078 | * |
| 1079 | * threshold '->nr_accesses' diff threshold for the merge |
| 1080 | * sz_limit size upper limit of each region |
| 1081 | * |
| 1082 | * This function merges monitoring target regions which are adjacent and their |
| 1083 | * access frequencies are similar. This is for minimizing the monitoring |
| 1084 | * overhead under the dynamically changeable access pattern. If a merge was |
| 1085 | * unnecessarily made, later 'kdamond_split_regions()' will revert it. |
| 1086 | */ |
| 1087 | static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold, |
| 1088 | unsigned long sz_limit) |
| 1089 | { |
| 1090 | struct damon_target *t; |
| 1091 | |
| 1092 | damon_for_each_target(t, c) |
| 1093 | damon_merge_regions_of(t, threshold, sz_limit); |
| 1094 | } |
| 1095 | |
| 1096 | /* |
| 1097 | * Split a region in two |
| 1098 | * |
| 1099 | * r the region to be split |
| 1100 | * sz_r size of the first sub-region that will be made |
| 1101 | */ |
| 1102 | static void damon_split_region_at(struct damon_target *t, |
| 1103 | struct damon_region *r, unsigned long sz_r) |
| 1104 | { |
| 1105 | struct damon_region *new; |
| 1106 | |
| 1107 | new = damon_new_region(r->ar.start + sz_r, r->ar.end); |
| 1108 | if (!new) |
| 1109 | return; |
| 1110 | |
| 1111 | r->ar.end = new->ar.start; |
| 1112 | |
| 1113 | new->age = r->age; |
| 1114 | new->last_nr_accesses = r->last_nr_accesses; |
| 1115 | |
| 1116 | damon_insert_region(new, r, damon_next_region(r), t); |
| 1117 | } |
| 1118 | |
| 1119 | /* Split every region in the given target into 'nr_subs' regions */ |
| 1120 | static void damon_split_regions_of(struct damon_target *t, int nr_subs) |
| 1121 | { |
| 1122 | struct damon_region *r, *next; |
| 1123 | unsigned long sz_region, sz_sub = 0; |
| 1124 | int i; |
| 1125 | |
| 1126 | damon_for_each_region_safe(r, next, t) { |
| 1127 | sz_region = damon_sz_region(r); |
| 1128 | |
| 1129 | for (i = 0; i < nr_subs - 1 && |
| 1130 | sz_region > 2 * DAMON_MIN_REGION; i++) { |
| 1131 | /* |
| 1132 | * Randomly select size of left sub-region to be at |
| 1133 | * least 10 percent and at most 90% of original region |
| 1134 | */ |
| 1135 | sz_sub = ALIGN_DOWN(damon_rand(1, 10) * |
| 1136 | sz_region / 10, DAMON_MIN_REGION); |
| 1137 | /* Do not allow blank region */ |
| 1138 | if (sz_sub == 0 || sz_sub >= sz_region) |
| 1139 | continue; |
| 1140 | |
| 1141 | damon_split_region_at(t, r, sz_sub); |
| 1142 | sz_region = sz_sub; |
| 1143 | } |
| 1144 | } |
| 1145 | } |
| 1146 | |
| 1147 | /* |
| 1148 | * Split every target region into randomly-sized small regions |
| 1149 | * |
| 1150 | * This function splits every target region into random-sized small regions if |
| 1151 | * current total number of the regions is equal or smaller than half of the |
| 1152 | * user-specified maximum number of regions. This is for maximizing the |
| 1153 | * monitoring accuracy under the dynamically changeable access patterns. If a |
| 1154 | * split was unnecessarily made, later 'kdamond_merge_regions()' will revert |
| 1155 | * it. |
| 1156 | */ |
| 1157 | static void kdamond_split_regions(struct damon_ctx *ctx) |
| 1158 | { |
| 1159 | struct damon_target *t; |
| 1160 | unsigned int nr_regions = 0; |
| 1161 | static unsigned int last_nr_regions; |
| 1162 | int nr_subregions = 2; |
| 1163 | |
| 1164 | damon_for_each_target(t, ctx) |
| 1165 | nr_regions += damon_nr_regions(t); |
| 1166 | |
| 1167 | if (nr_regions > ctx->attrs.max_nr_regions / 2) |
| 1168 | return; |
| 1169 | |
| 1170 | /* Maybe the middle of the region has different access frequency */ |
| 1171 | if (last_nr_regions == nr_regions && |
| 1172 | nr_regions < ctx->attrs.max_nr_regions / 3) |
| 1173 | nr_subregions = 3; |
| 1174 | |
| 1175 | damon_for_each_target(t, ctx) |
| 1176 | damon_split_regions_of(t, nr_subregions); |
| 1177 | |
| 1178 | last_nr_regions = nr_regions; |
| 1179 | } |
| 1180 | |
| 1181 | /* |
| 1182 | * Check whether it is time to check and apply the operations-related data |
| 1183 | * structures. |
| 1184 | * |
| 1185 | * Returns true if it is. |
| 1186 | */ |
| 1187 | static bool kdamond_need_update_operations(struct damon_ctx *ctx) |
| 1188 | { |
| 1189 | return damon_check_reset_time_interval(&ctx->last_ops_update, |
| 1190 | ctx->attrs.ops_update_interval); |
| 1191 | } |
| 1192 | |
| 1193 | /* |
| 1194 | * Check whether current monitoring should be stopped |
| 1195 | * |
| 1196 | * The monitoring is stopped when either the user requested to stop, or all |
| 1197 | * monitoring targets are invalid. |
| 1198 | * |
| 1199 | * Returns true if need to stop current monitoring. |
| 1200 | */ |
| 1201 | static bool kdamond_need_stop(struct damon_ctx *ctx) |
| 1202 | { |
| 1203 | struct damon_target *t; |
| 1204 | |
| 1205 | if (kthread_should_stop()) |
| 1206 | return true; |
| 1207 | |
| 1208 | if (!ctx->ops.target_valid) |
| 1209 | return false; |
| 1210 | |
| 1211 | damon_for_each_target(t, ctx) { |
| 1212 | if (ctx->ops.target_valid(t)) |
| 1213 | return false; |
| 1214 | } |
| 1215 | |
| 1216 | return true; |
| 1217 | } |
| 1218 | |
| 1219 | static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric) |
| 1220 | { |
| 1221 | struct sysinfo i; |
| 1222 | |
| 1223 | switch (metric) { |
| 1224 | case DAMOS_WMARK_FREE_MEM_RATE: |
| 1225 | si_meminfo(&i); |
| 1226 | return i.freeram * 1000 / i.totalram; |
| 1227 | default: |
| 1228 | break; |
| 1229 | } |
| 1230 | return -EINVAL; |
| 1231 | } |
| 1232 | |
| 1233 | /* |
| 1234 | * Returns zero if the scheme is active. Else, returns time to wait for next |
| 1235 | * watermark check in micro-seconds. |
| 1236 | */ |
| 1237 | static unsigned long damos_wmark_wait_us(struct damos *scheme) |
| 1238 | { |
| 1239 | unsigned long metric; |
| 1240 | |
| 1241 | if (scheme->wmarks.metric == DAMOS_WMARK_NONE) |
| 1242 | return 0; |
| 1243 | |
| 1244 | metric = damos_wmark_metric_value(scheme->wmarks.metric); |
| 1245 | /* higher than high watermark or lower than low watermark */ |
| 1246 | if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) { |
| 1247 | if (scheme->wmarks.activated) |
| 1248 | pr_debug("deactivate a scheme (%d) for %s wmark\n", |
| 1249 | scheme->action, |
| 1250 | metric > scheme->wmarks.high ? |
| 1251 | "high" : "low"); |
| 1252 | scheme->wmarks.activated = false; |
| 1253 | return scheme->wmarks.interval; |
| 1254 | } |
| 1255 | |
| 1256 | /* inactive and higher than middle watermark */ |
| 1257 | if ((scheme->wmarks.high >= metric && metric >= scheme->wmarks.mid) && |
| 1258 | !scheme->wmarks.activated) |
| 1259 | return scheme->wmarks.interval; |
| 1260 | |
| 1261 | if (!scheme->wmarks.activated) |
| 1262 | pr_debug("activate a scheme (%d)\n", scheme->action); |
| 1263 | scheme->wmarks.activated = true; |
| 1264 | return 0; |
| 1265 | } |
| 1266 | |
| 1267 | static void kdamond_usleep(unsigned long usecs) |
| 1268 | { |
| 1269 | /* See Documentation/timers/timers-howto.rst for the thresholds */ |
| 1270 | if (usecs > 20 * USEC_PER_MSEC) |
| 1271 | schedule_timeout_idle(usecs_to_jiffies(usecs)); |
| 1272 | else |
| 1273 | usleep_idle_range(usecs, usecs + 1); |
| 1274 | } |
| 1275 | |
| 1276 | /* Returns negative error code if it's not activated but should return */ |
| 1277 | static int kdamond_wait_activation(struct damon_ctx *ctx) |
| 1278 | { |
| 1279 | struct damos *s; |
| 1280 | unsigned long wait_time; |
| 1281 | unsigned long min_wait_time = 0; |
| 1282 | bool init_wait_time = false; |
| 1283 | |
| 1284 | while (!kdamond_need_stop(ctx)) { |
| 1285 | damon_for_each_scheme(s, ctx) { |
| 1286 | wait_time = damos_wmark_wait_us(s); |
| 1287 | if (!init_wait_time || wait_time < min_wait_time) { |
| 1288 | init_wait_time = true; |
| 1289 | min_wait_time = wait_time; |
| 1290 | } |
| 1291 | } |
| 1292 | if (!min_wait_time) |
| 1293 | return 0; |
| 1294 | |
| 1295 | kdamond_usleep(min_wait_time); |
| 1296 | |
| 1297 | if (ctx->callback.after_wmarks_check && |
| 1298 | ctx->callback.after_wmarks_check(ctx)) |
| 1299 | break; |
| 1300 | } |
| 1301 | return -EBUSY; |
| 1302 | } |
| 1303 | |
| 1304 | /* |
| 1305 | * The monitoring daemon that runs as a kernel thread |
| 1306 | */ |
| 1307 | static int kdamond_fn(void *data) |
| 1308 | { |
| 1309 | struct damon_ctx *ctx = data; |
| 1310 | struct damon_target *t; |
| 1311 | struct damon_region *r, *next; |
| 1312 | unsigned int max_nr_accesses = 0; |
| 1313 | unsigned long sz_limit = 0; |
| 1314 | |
| 1315 | pr_debug("kdamond (%d) starts\n", current->pid); |
| 1316 | |
| 1317 | if (ctx->ops.init) |
| 1318 | ctx->ops.init(ctx); |
| 1319 | if (ctx->callback.before_start && ctx->callback.before_start(ctx)) |
| 1320 | goto done; |
| 1321 | |
| 1322 | sz_limit = damon_region_sz_limit(ctx); |
| 1323 | |
| 1324 | while (!kdamond_need_stop(ctx)) { |
| 1325 | if (kdamond_wait_activation(ctx)) |
| 1326 | break; |
| 1327 | |
| 1328 | if (ctx->ops.prepare_access_checks) |
| 1329 | ctx->ops.prepare_access_checks(ctx); |
| 1330 | if (ctx->callback.after_sampling && |
| 1331 | ctx->callback.after_sampling(ctx)) |
| 1332 | break; |
| 1333 | |
| 1334 | kdamond_usleep(ctx->attrs.sample_interval); |
| 1335 | |
| 1336 | if (ctx->ops.check_accesses) |
| 1337 | max_nr_accesses = ctx->ops.check_accesses(ctx); |
| 1338 | |
| 1339 | if (kdamond_aggregate_interval_passed(ctx)) { |
| 1340 | kdamond_merge_regions(ctx, |
| 1341 | max_nr_accesses / 10, |
| 1342 | sz_limit); |
| 1343 | if (ctx->callback.after_aggregation && |
| 1344 | ctx->callback.after_aggregation(ctx)) |
| 1345 | break; |
| 1346 | if (!list_empty(&ctx->schemes)) |
| 1347 | kdamond_apply_schemes(ctx); |
| 1348 | kdamond_reset_aggregated(ctx); |
| 1349 | kdamond_split_regions(ctx); |
| 1350 | if (ctx->ops.reset_aggregated) |
| 1351 | ctx->ops.reset_aggregated(ctx); |
| 1352 | } |
| 1353 | |
| 1354 | if (kdamond_need_update_operations(ctx)) { |
| 1355 | if (ctx->ops.update) |
| 1356 | ctx->ops.update(ctx); |
| 1357 | sz_limit = damon_region_sz_limit(ctx); |
| 1358 | } |
| 1359 | } |
| 1360 | done: |
| 1361 | damon_for_each_target(t, ctx) { |
| 1362 | damon_for_each_region_safe(r, next, t) |
| 1363 | damon_destroy_region(r, t); |
| 1364 | } |
| 1365 | |
| 1366 | if (ctx->callback.before_terminate) |
| 1367 | ctx->callback.before_terminate(ctx); |
| 1368 | if (ctx->ops.cleanup) |
| 1369 | ctx->ops.cleanup(ctx); |
| 1370 | |
| 1371 | pr_debug("kdamond (%d) finishes\n", current->pid); |
| 1372 | mutex_lock(&ctx->kdamond_lock); |
| 1373 | ctx->kdamond = NULL; |
| 1374 | mutex_unlock(&ctx->kdamond_lock); |
| 1375 | |
| 1376 | mutex_lock(&damon_lock); |
| 1377 | nr_running_ctxs--; |
| 1378 | if (!nr_running_ctxs && running_exclusive_ctxs) |
| 1379 | running_exclusive_ctxs = false; |
| 1380 | mutex_unlock(&damon_lock); |
| 1381 | |
| 1382 | return 0; |
| 1383 | } |
| 1384 | |
| 1385 | /* |
| 1386 | * struct damon_system_ram_region - System RAM resource address region of |
| 1387 | * [@start, @end). |
| 1388 | * @start: Start address of the region (inclusive). |
| 1389 | * @end: End address of the region (exclusive). |
| 1390 | */ |
| 1391 | struct damon_system_ram_region { |
| 1392 | unsigned long start; |
| 1393 | unsigned long end; |
| 1394 | }; |
| 1395 | |
| 1396 | static int walk_system_ram(struct resource *res, void *arg) |
| 1397 | { |
| 1398 | struct damon_system_ram_region *a = arg; |
| 1399 | |
| 1400 | if (a->end - a->start < resource_size(res)) { |
| 1401 | a->start = res->start; |
| 1402 | a->end = res->end; |
| 1403 | } |
| 1404 | return 0; |
| 1405 | } |
| 1406 | |
| 1407 | /* |
| 1408 | * Find biggest 'System RAM' resource and store its start and end address in |
| 1409 | * @start and @end, respectively. If no System RAM is found, returns false. |
| 1410 | */ |
| 1411 | static bool damon_find_biggest_system_ram(unsigned long *start, |
| 1412 | unsigned long *end) |
| 1413 | |
| 1414 | { |
| 1415 | struct damon_system_ram_region arg = {}; |
| 1416 | |
| 1417 | walk_system_ram_res(0, ULONG_MAX, &arg, walk_system_ram); |
| 1418 | if (arg.end <= arg.start) |
| 1419 | return false; |
| 1420 | |
| 1421 | *start = arg.start; |
| 1422 | *end = arg.end; |
| 1423 | return true; |
| 1424 | } |
| 1425 | |
| 1426 | /** |
| 1427 | * damon_set_region_biggest_system_ram_default() - Set the region of the given |
| 1428 | * monitoring target as requested, or biggest 'System RAM'. |
| 1429 | * @t: The monitoring target to set the region. |
| 1430 | * @start: The pointer to the start address of the region. |
| 1431 | * @end: The pointer to the end address of the region. |
| 1432 | * |
| 1433 | * This function sets the region of @t as requested by @start and @end. If the |
| 1434 | * values of @start and @end are zero, however, this function finds the biggest |
| 1435 | * 'System RAM' resource and sets the region to cover the resource. In the |
| 1436 | * latter case, this function saves the start and end addresses of the resource |
| 1437 | * in @start and @end, respectively. |
| 1438 | * |
| 1439 | * Return: 0 on success, negative error code otherwise. |
| 1440 | */ |
| 1441 | int damon_set_region_biggest_system_ram_default(struct damon_target *t, |
| 1442 | unsigned long *start, unsigned long *end) |
| 1443 | { |
| 1444 | struct damon_addr_range addr_range; |
| 1445 | |
| 1446 | if (*start > *end) |
| 1447 | return -EINVAL; |
| 1448 | |
| 1449 | if (!*start && !*end && |
| 1450 | !damon_find_biggest_system_ram(start, end)) |
| 1451 | return -EINVAL; |
| 1452 | |
| 1453 | addr_range.start = *start; |
| 1454 | addr_range.end = *end; |
| 1455 | return damon_set_regions(t, &addr_range, 1); |
| 1456 | } |
| 1457 | |
| 1458 | static int __init damon_init(void) |
| 1459 | { |
| 1460 | damon_region_cache = KMEM_CACHE(damon_region, 0); |
| 1461 | if (unlikely(!damon_region_cache)) { |
| 1462 | pr_err("creating damon_region_cache fails\n"); |
| 1463 | return -ENOMEM; |
| 1464 | } |
| 1465 | |
| 1466 | return 0; |
| 1467 | } |
| 1468 | |
| 1469 | subsys_initcall(damon_init); |
| 1470 | |
| 1471 | #include "core-test.h" |