1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DAMON-based LRU-lists Sorting 4 * 5 * Author: SeongJae Park <sj@kernel.org> 6 */ 7 8 #define pr_fmt(fmt) "damon-lru-sort: " fmt 9 10 #include <linux/damon.h> 11 #include <linux/kstrtox.h> 12 #include <linux/module.h> 13 14 #include "modules-common.h" 15 16 #ifdef MODULE_PARAM_PREFIX 17 #undef MODULE_PARAM_PREFIX 18 #endif 19 #define MODULE_PARAM_PREFIX "damon_lru_sort." 20 21 /* 22 * Enable or disable DAMON_LRU_SORT. 23 * 24 * You can enable DAMON_LRU_SORT by setting the value of this parameter as 25 * ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that 26 * DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the 27 * watermarks-based activation condition. Refer to below descriptions for the 28 * watermarks parameter for this. 29 */ 30 static bool enabled __read_mostly; 31 32 /* 33 * Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``. 34 * 35 * Input parameters that updated while DAMON_LRU_SORT is running are not 36 * applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT 37 * reads values of parameters except ``enabled`` again. Once the re-reading is 38 * done, this parameter is set as ``N``. If invalid parameters are found while 39 * the re-reading, DAMON_LRU_SORT will be disabled. 40 */ 41 static bool commit_inputs __read_mostly; 42 module_param(commit_inputs, bool, 0600); 43 44 /* 45 * Desired active to [in]active memory ratio in bp (1/10,000). 46 * 47 * While keeping the caps that set by other quotas, DAMON_LRU_SORT 48 * automatically increases and decreases the effective level of the quota 49 * aiming the LRU [de]prioritizations of the hot and cold memory resulting in 50 * this active to [in]active memory ratio. Value zero means disabling this 51 * auto-tuning feature. 52 * 53 * Disabled by default. 54 */ 55 static unsigned long active_mem_bp __read_mostly; 56 module_param(active_mem_bp, ulong, 0600); 57 58 /* 59 * Auto-tune monitoring intervals. 60 * 61 * If this parameter is set as ``Y``, DAMON_LRU_SORT automatically tunes 62 * DAMON's sampling and aggregation intervals. The auto-tuning aims to capture 63 * meaningful amount of access events in each DAMON-snapshot, while keeping the 64 * sampling interval 5 milliseconds in minimum, and 10 seconds in maximum. 65 * Setting this as ``N`` disables the auto-tuning. 66 * 67 * Disabled by default. 68 */ 69 static bool autotune_monitoring_intervals __read_mostly; 70 module_param(autotune_monitoring_intervals, bool, 0600); 71 72 /* 73 * Filter [non-]young pages accordingly for LRU [de]prioritizations. 74 * 75 * If this is set, check page level access (youngness) once again before each 76 * LRU [de]prioritization operation. LRU prioritization operation is skipped 77 * if the page has not accessed since the last check (not young). LRU 78 * deprioritization operation is skipped if the page has accessed since the 79 * last check (young). The feature is enabled or disabled if this parameter is 80 * set as ``Y`` or ``N``, respectively. 81 * 82 * Disabled by default. 83 */ 84 static bool filter_young_pages __read_mostly; 85 module_param(filter_young_pages, bool, 0600); 86 87 /* 88 * Access frequency threshold for hot memory regions identification in permil. 89 * 90 * If a memory region is accessed in frequency of this or higher, 91 * DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the 92 * LRU list, so that it could not be reclaimed under memory pressure. 50% by 93 * default. 94 */ 95 static unsigned long hot_thres_access_freq = 500; 96 module_param(hot_thres_access_freq, ulong, 0600); 97 98 /* 99 * Time threshold for cold memory regions identification in microseconds. 100 * 101 * If a memory region is not accessed for this or longer time, DAMON_LRU_SORT 102 * identifies the region as cold, and mark it as unaccessed on the LRU list, so 103 * that it could be reclaimed first under memory pressure. 120 seconds by 104 * default. 105 */ 106 static unsigned long cold_min_age __read_mostly = 120000000; 107 module_param(cold_min_age, ulong, 0600); 108 109 static struct damos_quota damon_lru_sort_quota = { 110 /* Use up to 10 ms per 1 sec, by default */ 111 .ms = 10, 112 .sz = 0, 113 .reset_interval = 1000, 114 /* Within the quota, mark hotter regions accessed first. */ 115 .weight_sz = 0, 116 .weight_nr_accesses = 1, 117 .weight_age = 1, 118 }; 119 DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota); 120 121 static struct damos_watermarks damon_lru_sort_wmarks = { 122 .metric = DAMOS_WMARK_FREE_MEM_RATE, 123 .interval = 5000000, /* 5 seconds */ 124 .high = 200, /* 20 percent */ 125 .mid = 150, /* 15 percent */ 126 .low = 50, /* 5 percent */ 127 }; 128 DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks); 129 130 static struct damon_attrs damon_lru_sort_mon_attrs = { 131 .sample_interval = 5000, /* 5 ms */ 132 .aggr_interval = 100000, /* 100 ms */ 133 .ops_update_interval = 0, 134 .min_nr_regions = 10, 135 .max_nr_regions = 1000, 136 }; 137 DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_lru_sort_mon_attrs); 138 139 /* 140 * Start of the target memory region in physical address. 141 * 142 * The start physical address of memory region that DAMON_LRU_SORT will do work 143 * against. By default, biggest System RAM is used as the region. 144 */ 145 static unsigned long monitor_region_start __read_mostly; 146 module_param(monitor_region_start, ulong, 0600); 147 148 /* 149 * End of the target memory region in physical address. 150 * 151 * The end physical address of memory region that DAMON_LRU_SORT will do work 152 * against. By default, biggest System RAM is used as the region. 153 */ 154 static unsigned long monitor_region_end __read_mostly; 155 module_param(monitor_region_end, ulong, 0600); 156 157 /* 158 * Scale factor for DAMON_LRU_SORT to ops address conversion. 159 * 160 * This parameter must not be set to 0. 161 */ 162 static unsigned long addr_unit __read_mostly = 1; 163 164 /* 165 * PID of the DAMON thread 166 * 167 * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread. 168 * Else, -1. 169 */ 170 static int kdamond_pid __read_mostly = -1; 171 module_param(kdamond_pid, int, 0400); 172 173 static struct damos_stat damon_lru_sort_hot_stat; 174 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat, 175 lru_sort_tried_hot_regions, lru_sorted_hot_regions, 176 hot_quota_exceeds); 177 178 static struct damos_stat damon_lru_sort_cold_stat; 179 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, 180 lru_sort_tried_cold_regions, lru_sorted_cold_regions, 181 cold_quota_exceeds); 182 183 static struct damos_access_pattern damon_lru_sort_stub_pattern = { 184 /* Find regions having PAGE_SIZE or larger size */ 185 .min_sz_region = PAGE_SIZE, 186 .max_sz_region = ULONG_MAX, 187 /* no matter its access frequency */ 188 .min_nr_accesses = 0, 189 .max_nr_accesses = UINT_MAX, 190 /* no matter its age */ 191 .min_age_region = 0, 192 .max_age_region = UINT_MAX, 193 }; 194 195 static struct damon_ctx *ctx; 196 static struct damon_target *target; 197 198 static struct damos *damon_lru_sort_new_scheme( 199 struct damos_access_pattern *pattern, enum damos_action action) 200 { 201 struct damos_quota quota = damon_lru_sort_quota; 202 203 /* Use half of total quota for hot/cold pages sorting */ 204 quota.ms = quota.ms / 2; 205 206 return damon_new_scheme( 207 /* find the pattern, and */ 208 pattern, 209 /* (de)prioritize on LRU-lists */ 210 action, 211 /* for each aggregation interval */ 212 0, 213 /* under the quota. */ 214 "a, 215 /* (De)activate this according to the watermarks. */ 216 &damon_lru_sort_wmarks, 217 NUMA_NO_NODE); 218 } 219 220 /* Create a DAMON-based operation scheme for hot memory regions */ 221 static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres) 222 { 223 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 224 225 pattern.min_nr_accesses = hot_thres; 226 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); 227 } 228 229 /* Create a DAMON-based operation scheme for cold memory regions */ 230 static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres) 231 { 232 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 233 234 pattern.max_nr_accesses = 0; 235 pattern.min_age_region = cold_thres; 236 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO); 237 } 238 239 static int damon_lru_sort_add_quota_goals(struct damos *hot_scheme, 240 struct damos *cold_scheme) 241 { 242 struct damos_quota_goal *goal; 243 244 if (!active_mem_bp) 245 return 0; 246 goal = damos_new_quota_goal(DAMOS_QUOTA_ACTIVE_MEM_BP, active_mem_bp); 247 if (!goal) 248 return -ENOMEM; 249 damos_add_quota_goal(&hot_scheme->quota, goal); 250 /* aim 0.2 % goal conflict, to keep little ping pong */ 251 goal = damos_new_quota_goal(DAMOS_QUOTA_INACTIVE_MEM_BP, 252 10000 - active_mem_bp + 2); 253 if (!goal) 254 return -ENOMEM; 255 damos_add_quota_goal(&cold_scheme->quota, goal); 256 return 0; 257 } 258 259 static int damon_lru_sort_add_filters(struct damos *hot_scheme, 260 struct damos *cold_scheme) 261 { 262 struct damos_filter *filter; 263 264 if (!filter_young_pages) 265 return 0; 266 267 /* disallow prioritizing not-young pages */ 268 filter = damos_new_filter(DAMOS_FILTER_TYPE_YOUNG, false, false); 269 if (!filter) 270 return -ENOMEM; 271 damos_add_filter(hot_scheme, filter); 272 273 /* disabllow de-prioritizing young pages */ 274 filter = damos_new_filter(DAMOS_FILTER_TYPE_YOUNG, true, false); 275 if (!filter) 276 return -ENOMEM; 277 damos_add_filter(cold_scheme, filter); 278 return 0; 279 } 280 281 static int damon_lru_sort_apply_parameters(void) 282 { 283 struct damon_ctx *param_ctx; 284 struct damon_target *param_target; 285 struct damon_attrs attrs; 286 struct damos *hot_scheme, *cold_scheme; 287 unsigned int hot_thres, cold_thres; 288 int err; 289 290 err = damon_modules_new_paddr_ctx_target(¶m_ctx, ¶m_target); 291 if (err) 292 return err; 293 294 /* 295 * If monitor_region_start/end are unset, always silently 296 * reset addr_unit to 1. 297 */ 298 if (!monitor_region_start && !monitor_region_end) 299 addr_unit = 1; 300 param_ctx->addr_unit = addr_unit; 301 param_ctx->min_region_sz = max(DAMON_MIN_REGION_SZ / addr_unit, 1); 302 303 if (!damon_lru_sort_mon_attrs.sample_interval) { 304 err = -EINVAL; 305 goto out; 306 } 307 308 attrs = damon_lru_sort_mon_attrs; 309 if (autotune_monitoring_intervals) { 310 attrs.sample_interval = 5000; 311 attrs.aggr_interval = 100000; 312 attrs.intervals_goal.access_bp = 40; 313 attrs.intervals_goal.aggrs = 3; 314 attrs.intervals_goal.min_sample_us = 5000; 315 attrs.intervals_goal.max_sample_us = 10 * 1000 * 1000; 316 } 317 err = damon_set_attrs(param_ctx, &attrs); 318 if (err) 319 goto out; 320 321 err = -ENOMEM; 322 hot_thres = damon_max_nr_accesses(&attrs) * 323 hot_thres_access_freq / 1000; 324 hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres); 325 if (!hot_scheme) 326 goto out; 327 328 cold_thres = cold_min_age / attrs.aggr_interval; 329 cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres); 330 if (!cold_scheme) { 331 damon_destroy_scheme(hot_scheme); 332 goto out; 333 } 334 335 damon_set_schemes(param_ctx, &hot_scheme, 1); 336 damon_add_scheme(param_ctx, cold_scheme); 337 338 err = damon_lru_sort_add_quota_goals(hot_scheme, cold_scheme); 339 if (err) 340 goto out; 341 err = damon_lru_sort_add_filters(hot_scheme, cold_scheme); 342 if (err) 343 goto out; 344 345 err = damon_set_region_biggest_system_ram_default(param_target, 346 &monitor_region_start, 347 &monitor_region_end, 348 param_ctx->min_region_sz); 349 if (err) 350 goto out; 351 err = damon_commit_ctx(ctx, param_ctx); 352 out: 353 damon_destroy_ctx(param_ctx); 354 return err; 355 } 356 357 static int damon_lru_sort_handle_commit_inputs(void) 358 { 359 int err; 360 361 if (!commit_inputs) 362 return 0; 363 364 err = damon_lru_sort_apply_parameters(); 365 commit_inputs = false; 366 return err; 367 } 368 369 static int damon_lru_sort_damon_call_fn(void *arg) 370 { 371 struct damon_ctx *c = arg; 372 struct damos *s; 373 374 /* update the stats parameter */ 375 damon_for_each_scheme(s, c) { 376 if (s->action == DAMOS_LRU_PRIO) 377 damon_lru_sort_hot_stat = s->stat; 378 else if (s->action == DAMOS_LRU_DEPRIO) 379 damon_lru_sort_cold_stat = s->stat; 380 } 381 382 return damon_lru_sort_handle_commit_inputs(); 383 } 384 385 static struct damon_call_control call_control = { 386 .fn = damon_lru_sort_damon_call_fn, 387 .repeat = true, 388 }; 389 390 static int damon_lru_sort_turn(bool on) 391 { 392 int err; 393 394 if (!on) { 395 err = damon_stop(&ctx, 1); 396 if (!err) 397 kdamond_pid = -1; 398 return err; 399 } 400 401 err = damon_lru_sort_apply_parameters(); 402 if (err) 403 return err; 404 405 err = damon_start(&ctx, 1, true); 406 if (err) 407 return err; 408 kdamond_pid = damon_kdamond_pid(ctx); 409 if (kdamond_pid < 0) 410 return kdamond_pid; 411 return damon_call(ctx, &call_control); 412 } 413 414 static int damon_lru_sort_addr_unit_store(const char *val, 415 const struct kernel_param *kp) 416 { 417 unsigned long input_addr_unit; 418 int err = kstrtoul(val, 0, &input_addr_unit); 419 420 if (err) 421 return err; 422 if (!input_addr_unit) 423 return -EINVAL; 424 425 addr_unit = input_addr_unit; 426 return 0; 427 } 428 429 static const struct kernel_param_ops addr_unit_param_ops = { 430 .set = damon_lru_sort_addr_unit_store, 431 .get = param_get_ulong, 432 }; 433 434 module_param_cb(addr_unit, &addr_unit_param_ops, &addr_unit, 0600); 435 MODULE_PARM_DESC(addr_unit, 436 "Scale factor for DAMON_LRU_SORT to ops address conversion (default: 1)"); 437 438 static int damon_lru_sort_enabled_store(const char *val, 439 const struct kernel_param *kp) 440 { 441 bool is_enabled = enabled; 442 bool enable; 443 int err; 444 445 err = kstrtobool(val, &enable); 446 if (err) 447 return err; 448 449 if (is_enabled == enable) 450 return 0; 451 452 /* Called before init function. The function will handle this. */ 453 if (!damon_initialized()) 454 goto set_param_out; 455 456 err = damon_lru_sort_turn(enable); 457 if (err) 458 return err; 459 460 set_param_out: 461 enabled = enable; 462 return err; 463 } 464 465 static const struct kernel_param_ops enabled_param_ops = { 466 .set = damon_lru_sort_enabled_store, 467 .get = param_get_bool, 468 }; 469 470 module_param_cb(enabled, &enabled_param_ops, &enabled, 0600); 471 MODULE_PARM_DESC(enabled, 472 "Enable or disable DAMON_LRU_SORT (default: disabled)"); 473 474 static int __init damon_lru_sort_init(void) 475 { 476 int err; 477 478 if (!damon_initialized()) { 479 err = -ENOMEM; 480 goto out; 481 } 482 err = damon_modules_new_paddr_ctx_target(&ctx, &target); 483 if (err) 484 goto out; 485 486 call_control.data = ctx; 487 488 /* 'enabled' has set before this function, probably via command line */ 489 if (enabled) 490 err = damon_lru_sort_turn(true); 491 492 out: 493 if (err && enabled) 494 enabled = false; 495 return err; 496 } 497 498 module_init(damon_lru_sort_init); 499