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 parametrs 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 * Access frequency threshold for hot memory regions identification in permil. 46 * 47 * If a memory region is accessed in frequency of this or higher, 48 * DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the 49 * LRU list, so that it could not be reclaimed under memory pressure. 50% by 50 * default. 51 */ 52 static unsigned long hot_thres_access_freq = 500; 53 module_param(hot_thres_access_freq, ulong, 0600); 54 55 /* 56 * Time threshold for cold memory regions identification in microseconds. 57 * 58 * If a memory region is not accessed for this or longer time, DAMON_LRU_SORT 59 * identifies the region as cold, and mark it as unaccessed on the LRU list, so 60 * that it could be reclaimed first under memory pressure. 120 seconds by 61 * default. 62 */ 63 static unsigned long cold_min_age __read_mostly = 120000000; 64 module_param(cold_min_age, ulong, 0600); 65 66 static struct damos_quota damon_lru_sort_quota = { 67 /* Use up to 10 ms per 1 sec, by default */ 68 .ms = 10, 69 .sz = 0, 70 .reset_interval = 1000, 71 /* Within the quota, mark hotter regions accessed first. */ 72 .weight_sz = 0, 73 .weight_nr_accesses = 1, 74 .weight_age = 0, 75 }; 76 DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota); 77 78 static struct damos_watermarks damon_lru_sort_wmarks = { 79 .metric = DAMOS_WMARK_FREE_MEM_RATE, 80 .interval = 5000000, /* 5 seconds */ 81 .high = 200, /* 20 percent */ 82 .mid = 150, /* 15 percent */ 83 .low = 50, /* 5 percent */ 84 }; 85 DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks); 86 87 static struct damon_attrs damon_lru_sort_mon_attrs = { 88 .sample_interval = 5000, /* 5 ms */ 89 .aggr_interval = 100000, /* 100 ms */ 90 .ops_update_interval = 0, 91 .min_nr_regions = 10, 92 .max_nr_regions = 1000, 93 }; 94 DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_lru_sort_mon_attrs); 95 96 /* 97 * Start of the target memory region in physical address. 98 * 99 * The start physical address of memory region that DAMON_LRU_SORT will do work 100 * against. By default, biggest System RAM is used as the region. 101 */ 102 static unsigned long monitor_region_start __read_mostly; 103 module_param(monitor_region_start, ulong, 0600); 104 105 /* 106 * End of the target memory region in physical address. 107 * 108 * The end physical address of memory region that DAMON_LRU_SORT will do work 109 * against. By default, biggest System RAM is used as the region. 110 */ 111 static unsigned long monitor_region_end __read_mostly; 112 module_param(monitor_region_end, ulong, 0600); 113 114 /* 115 * Scale factor for DAMON_LRU_SORT to ops address conversion. 116 * 117 * This parameter must not be set to 0. 118 */ 119 static unsigned long addr_unit __read_mostly = 1; 120 121 /* 122 * PID of the DAMON thread 123 * 124 * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread. 125 * Else, -1. 126 */ 127 static int kdamond_pid __read_mostly = -1; 128 module_param(kdamond_pid, int, 0400); 129 130 static struct damos_stat damon_lru_sort_hot_stat; 131 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat, 132 lru_sort_tried_hot_regions, lru_sorted_hot_regions, 133 hot_quota_exceeds); 134 135 static struct damos_stat damon_lru_sort_cold_stat; 136 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, 137 lru_sort_tried_cold_regions, lru_sorted_cold_regions, 138 cold_quota_exceeds); 139 140 static struct damos_access_pattern damon_lru_sort_stub_pattern = { 141 /* Find regions having PAGE_SIZE or larger size */ 142 .min_sz_region = PAGE_SIZE, 143 .max_sz_region = ULONG_MAX, 144 /* no matter its access frequency */ 145 .min_nr_accesses = 0, 146 .max_nr_accesses = UINT_MAX, 147 /* no matter its age */ 148 .min_age_region = 0, 149 .max_age_region = UINT_MAX, 150 }; 151 152 static struct damon_ctx *ctx; 153 static struct damon_target *target; 154 155 static struct damos *damon_lru_sort_new_scheme( 156 struct damos_access_pattern *pattern, enum damos_action action) 157 { 158 struct damos_quota quota = damon_lru_sort_quota; 159 160 /* Use half of total quota for hot/cold pages sorting */ 161 quota.ms = quota.ms / 2; 162 163 return damon_new_scheme( 164 /* find the pattern, and */ 165 pattern, 166 /* (de)prioritize on LRU-lists */ 167 action, 168 /* for each aggregation interval */ 169 0, 170 /* under the quota. */ 171 "a, 172 /* (De)activate this according to the watermarks. */ 173 &damon_lru_sort_wmarks, 174 NUMA_NO_NODE); 175 } 176 177 /* Create a DAMON-based operation scheme for hot memory regions */ 178 static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres) 179 { 180 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 181 182 pattern.min_nr_accesses = hot_thres; 183 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); 184 } 185 186 /* Create a DAMON-based operation scheme for cold memory regions */ 187 static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres) 188 { 189 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 190 191 pattern.max_nr_accesses = 0; 192 pattern.min_age_region = cold_thres; 193 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO); 194 } 195 196 static int damon_lru_sort_apply_parameters(void) 197 { 198 struct damon_ctx *param_ctx; 199 struct damon_target *param_target; 200 struct damos *hot_scheme, *cold_scheme; 201 unsigned int hot_thres, cold_thres; 202 int err; 203 204 err = damon_modules_new_paddr_ctx_target(¶m_ctx, ¶m_target); 205 if (err) 206 return err; 207 208 /* 209 * If monitor_region_start/end are unset, always silently 210 * reset addr_unit to 1. 211 */ 212 if (!monitor_region_start && !monitor_region_end) 213 addr_unit = 1; 214 param_ctx->addr_unit = addr_unit; 215 param_ctx->min_sz_region = max(DAMON_MIN_REGION / addr_unit, 1); 216 217 if (!damon_lru_sort_mon_attrs.sample_interval) { 218 err = -EINVAL; 219 goto out; 220 } 221 222 err = damon_set_attrs(param_ctx, &damon_lru_sort_mon_attrs); 223 if (err) 224 goto out; 225 226 err = -ENOMEM; 227 hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) * 228 hot_thres_access_freq / 1000; 229 hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres); 230 if (!hot_scheme) 231 goto out; 232 233 cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval; 234 cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres); 235 if (!cold_scheme) { 236 damon_destroy_scheme(hot_scheme); 237 goto out; 238 } 239 240 damon_set_schemes(param_ctx, &hot_scheme, 1); 241 damon_add_scheme(param_ctx, cold_scheme); 242 243 err = damon_set_region_biggest_system_ram_default(param_target, 244 &monitor_region_start, 245 &monitor_region_end, 246 param_ctx->min_sz_region); 247 if (err) 248 goto out; 249 err = damon_commit_ctx(ctx, param_ctx); 250 out: 251 damon_destroy_ctx(param_ctx); 252 return err; 253 } 254 255 static int damon_lru_sort_handle_commit_inputs(void) 256 { 257 int err; 258 259 if (!commit_inputs) 260 return 0; 261 262 err = damon_lru_sort_apply_parameters(); 263 commit_inputs = false; 264 return err; 265 } 266 267 static int damon_lru_sort_damon_call_fn(void *arg) 268 { 269 struct damon_ctx *c = arg; 270 struct damos *s; 271 272 /* update the stats parameter */ 273 damon_for_each_scheme(s, c) { 274 if (s->action == DAMOS_LRU_PRIO) 275 damon_lru_sort_hot_stat = s->stat; 276 else if (s->action == DAMOS_LRU_DEPRIO) 277 damon_lru_sort_cold_stat = s->stat; 278 } 279 280 return damon_lru_sort_handle_commit_inputs(); 281 } 282 283 static struct damon_call_control call_control = { 284 .fn = damon_lru_sort_damon_call_fn, 285 .repeat = true, 286 }; 287 288 static int damon_lru_sort_turn(bool on) 289 { 290 int err; 291 292 if (!on) { 293 err = damon_stop(&ctx, 1); 294 if (!err) 295 kdamond_pid = -1; 296 return err; 297 } 298 299 err = damon_lru_sort_apply_parameters(); 300 if (err) 301 return err; 302 303 err = damon_start(&ctx, 1, true); 304 if (err) 305 return err; 306 kdamond_pid = ctx->kdamond->pid; 307 return damon_call(ctx, &call_control); 308 } 309 310 static int damon_lru_sort_addr_unit_store(const char *val, 311 const struct kernel_param *kp) 312 { 313 unsigned long input_addr_unit; 314 int err = kstrtoul(val, 0, &input_addr_unit); 315 316 if (err) 317 return err; 318 if (!input_addr_unit) 319 return -EINVAL; 320 321 addr_unit = input_addr_unit; 322 return 0; 323 } 324 325 static const struct kernel_param_ops addr_unit_param_ops = { 326 .set = damon_lru_sort_addr_unit_store, 327 .get = param_get_ulong, 328 }; 329 330 module_param_cb(addr_unit, &addr_unit_param_ops, &addr_unit, 0600); 331 MODULE_PARM_DESC(addr_unit, 332 "Scale factor for DAMON_LRU_SORT to ops address conversion (default: 1)"); 333 334 static int damon_lru_sort_enabled_store(const char *val, 335 const struct kernel_param *kp) 336 { 337 bool is_enabled = enabled; 338 bool enable; 339 int err; 340 341 err = kstrtobool(val, &enable); 342 if (err) 343 return err; 344 345 if (is_enabled == enable) 346 return 0; 347 348 /* Called before init function. The function will handle this. */ 349 if (!damon_initialized()) 350 goto set_param_out; 351 352 err = damon_lru_sort_turn(enable); 353 if (err) 354 return err; 355 356 set_param_out: 357 enabled = enable; 358 return err; 359 } 360 361 static const struct kernel_param_ops enabled_param_ops = { 362 .set = damon_lru_sort_enabled_store, 363 .get = param_get_bool, 364 }; 365 366 module_param_cb(enabled, &enabled_param_ops, &enabled, 0600); 367 MODULE_PARM_DESC(enabled, 368 "Enable or disable DAMON_LRU_SORT (default: disabled)"); 369 370 static int __init damon_lru_sort_init(void) 371 { 372 int err; 373 374 if (!damon_initialized()) { 375 err = -ENOMEM; 376 goto out; 377 } 378 err = damon_modules_new_paddr_ctx_target(&ctx, &target); 379 if (err) 380 goto out; 381 382 call_control.data = ctx; 383 384 /* 'enabled' has set before this function, probably via command line */ 385 if (enabled) 386 err = damon_lru_sort_turn(true); 387 388 out: 389 if (err && enabled) 390 enabled = false; 391 return err; 392 } 393 394 module_init(damon_lru_sort_init); 395