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/ioport.h> 12 #include <linux/module.h> 13 #include <linux/sched.h> 14 #include <linux/workqueue.h> 15 16 #include "modules-common.h" 17 18 #ifdef MODULE_PARAM_PREFIX 19 #undef MODULE_PARAM_PREFIX 20 #endif 21 #define MODULE_PARAM_PREFIX "damon_lru_sort." 22 23 /* 24 * Enable or disable DAMON_LRU_SORT. 25 * 26 * You can enable DAMON_LRU_SORT by setting the value of this parameter as 27 * ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that 28 * DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the 29 * watermarks-based activation condition. Refer to below descriptions for the 30 * watermarks parameter for this. 31 */ 32 static bool enabled __read_mostly; 33 34 /* 35 * Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``. 36 * 37 * Input parameters that updated while DAMON_LRU_SORT is running are not 38 * applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT 39 * reads values of parametrs except ``enabled`` again. Once the re-reading is 40 * done, this parameter is set as ``N``. If invalid parameters are found while 41 * the re-reading, DAMON_LRU_SORT will be disabled. 42 */ 43 static bool commit_inputs __read_mostly; 44 module_param(commit_inputs, bool, 0600); 45 46 /* 47 * Access frequency threshold for hot memory regions identification in permil. 48 * 49 * If a memory region is accessed in frequency of this or higher, 50 * DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the 51 * LRU list, so that it could not be reclaimed under memory pressure. 50% by 52 * default. 53 */ 54 static unsigned long hot_thres_access_freq = 500; 55 module_param(hot_thres_access_freq, ulong, 0600); 56 57 /* 58 * Time threshold for cold memory regions identification in microseconds. 59 * 60 * If a memory region is not accessed for this or longer time, DAMON_LRU_SORT 61 * identifies the region as cold, and mark it as unaccessed on the LRU list, so 62 * that it could be reclaimed first under memory pressure. 120 seconds by 63 * default. 64 */ 65 static unsigned long cold_min_age __read_mostly = 120000000; 66 module_param(cold_min_age, ulong, 0600); 67 68 static struct damos_quota damon_lru_sort_quota = { 69 /* Use up to 10 ms per 1 sec, by default */ 70 .ms = 10, 71 .sz = 0, 72 .reset_interval = 1000, 73 /* Within the quota, mark hotter regions accessed first. */ 74 .weight_sz = 0, 75 .weight_nr_accesses = 1, 76 .weight_age = 0, 77 }; 78 DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota); 79 80 static struct damos_watermarks damon_lru_sort_wmarks = { 81 .metric = DAMOS_WMARK_FREE_MEM_RATE, 82 .interval = 5000000, /* 5 seconds */ 83 .high = 200, /* 20 percent */ 84 .mid = 150, /* 15 percent */ 85 .low = 50, /* 5 percent */ 86 }; 87 DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks); 88 89 static struct damon_attrs damon_lru_sort_mon_attrs = { 90 .sample_interval = 5000, /* 5 ms */ 91 .aggr_interval = 100000, /* 100 ms */ 92 .ops_update_interval = 0, 93 .min_nr_regions = 10, 94 .max_nr_regions = 1000, 95 }; 96 DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_lru_sort_mon_attrs); 97 98 /* 99 * Start of the target memory region in physical address. 100 * 101 * The start physical address of memory region that DAMON_LRU_SORT will do work 102 * against. By default, biggest System RAM is used as the region. 103 */ 104 static unsigned long monitor_region_start __read_mostly; 105 module_param(monitor_region_start, ulong, 0600); 106 107 /* 108 * End of the target memory region in physical address. 109 * 110 * The end physical address of memory region that DAMON_LRU_SORT will do work 111 * against. By default, biggest System RAM is used as the region. 112 */ 113 static unsigned long monitor_region_end __read_mostly; 114 module_param(monitor_region_end, ulong, 0600); 115 116 /* 117 * PID of the DAMON thread 118 * 119 * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread. 120 * Else, -1. 121 */ 122 static int kdamond_pid __read_mostly = -1; 123 module_param(kdamond_pid, int, 0400); 124 125 static struct damos_stat damon_lru_sort_hot_stat; 126 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat, 127 lru_sort_tried_hot_regions, lru_sorted_hot_regions, 128 hot_quota_exceeds); 129 130 static struct damos_stat damon_lru_sort_cold_stat; 131 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, 132 lru_sort_tried_cold_regions, lru_sorted_cold_regions, 133 cold_quota_exceeds); 134 135 static struct damos_access_pattern damon_lru_sort_stub_pattern = { 136 /* Find regions having PAGE_SIZE or larger size */ 137 .min_sz_region = PAGE_SIZE, 138 .max_sz_region = ULONG_MAX, 139 /* no matter its access frequency */ 140 .min_nr_accesses = 0, 141 .max_nr_accesses = UINT_MAX, 142 /* no matter its age */ 143 .min_age_region = 0, 144 .max_age_region = UINT_MAX, 145 }; 146 147 static struct damon_ctx *ctx; 148 static struct damon_target *target; 149 150 static struct damos *damon_lru_sort_new_scheme( 151 struct damos_access_pattern *pattern, enum damos_action action) 152 { 153 struct damos_quota quota = damon_lru_sort_quota; 154 155 /* Use half of total quota for hot/cold pages sorting */ 156 quota.ms = quota.ms / 2; 157 158 return damon_new_scheme( 159 /* find the pattern, and */ 160 pattern, 161 /* (de)prioritize on LRU-lists */ 162 action, 163 /* under the quota. */ 164 "a, 165 /* (De)activate this according to the watermarks. */ 166 &damon_lru_sort_wmarks); 167 } 168 169 /* Create a DAMON-based operation scheme for hot memory regions */ 170 static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres) 171 { 172 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 173 174 pattern.min_nr_accesses = hot_thres; 175 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); 176 } 177 178 /* Create a DAMON-based operation scheme for cold memory regions */ 179 static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres) 180 { 181 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; 182 183 pattern.max_nr_accesses = 0; 184 pattern.min_age_region = cold_thres; 185 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO); 186 } 187 188 static int damon_lru_sort_apply_parameters(void) 189 { 190 struct damos *scheme; 191 unsigned int hot_thres, cold_thres; 192 int err = 0; 193 194 err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs); 195 if (err) 196 return err; 197 198 /* aggr_interval / sample_interval is the maximum nr_accesses */ 199 hot_thres = damon_lru_sort_mon_attrs.aggr_interval / 200 damon_lru_sort_mon_attrs.sample_interval * 201 hot_thres_access_freq / 1000; 202 scheme = damon_lru_sort_new_hot_scheme(hot_thres); 203 if (!scheme) 204 return -ENOMEM; 205 damon_set_schemes(ctx, &scheme, 1); 206 207 cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval; 208 scheme = damon_lru_sort_new_cold_scheme(cold_thres); 209 if (!scheme) 210 return -ENOMEM; 211 damon_add_scheme(ctx, scheme); 212 213 return damon_set_region_biggest_system_ram_default(target, 214 &monitor_region_start, 215 &monitor_region_end); 216 } 217 218 static int damon_lru_sort_turn(bool on) 219 { 220 int err; 221 222 if (!on) { 223 err = damon_stop(&ctx, 1); 224 if (!err) 225 kdamond_pid = -1; 226 return err; 227 } 228 229 err = damon_lru_sort_apply_parameters(); 230 if (err) 231 return err; 232 233 err = damon_start(&ctx, 1, true); 234 if (err) 235 return err; 236 kdamond_pid = ctx->kdamond->pid; 237 return 0; 238 } 239 240 static struct delayed_work damon_lru_sort_timer; 241 static void damon_lru_sort_timer_fn(struct work_struct *work) 242 { 243 static bool last_enabled; 244 bool now_enabled; 245 246 now_enabled = enabled; 247 if (last_enabled != now_enabled) { 248 if (!damon_lru_sort_turn(now_enabled)) 249 last_enabled = now_enabled; 250 else 251 enabled = last_enabled; 252 } 253 } 254 static DECLARE_DELAYED_WORK(damon_lru_sort_timer, damon_lru_sort_timer_fn); 255 256 static bool damon_lru_sort_initialized; 257 258 static int damon_lru_sort_enabled_store(const char *val, 259 const struct kernel_param *kp) 260 { 261 int rc = param_set_bool(val, kp); 262 263 if (rc < 0) 264 return rc; 265 266 if (!damon_lru_sort_initialized) 267 return rc; 268 269 schedule_delayed_work(&damon_lru_sort_timer, 0); 270 271 return 0; 272 } 273 274 static const struct kernel_param_ops enabled_param_ops = { 275 .set = damon_lru_sort_enabled_store, 276 .get = param_get_bool, 277 }; 278 279 module_param_cb(enabled, &enabled_param_ops, &enabled, 0600); 280 MODULE_PARM_DESC(enabled, 281 "Enable or disable DAMON_LRU_SORT (default: disabled)"); 282 283 static int damon_lru_sort_handle_commit_inputs(void) 284 { 285 int err; 286 287 if (!commit_inputs) 288 return 0; 289 290 err = damon_lru_sort_apply_parameters(); 291 commit_inputs = false; 292 return err; 293 } 294 295 static int damon_lru_sort_after_aggregation(struct damon_ctx *c) 296 { 297 struct damos *s; 298 299 /* update the stats parameter */ 300 damon_for_each_scheme(s, c) { 301 if (s->action == DAMOS_LRU_PRIO) 302 damon_lru_sort_hot_stat = s->stat; 303 else if (s->action == DAMOS_LRU_DEPRIO) 304 damon_lru_sort_cold_stat = s->stat; 305 } 306 307 return damon_lru_sort_handle_commit_inputs(); 308 } 309 310 static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c) 311 { 312 return damon_lru_sort_handle_commit_inputs(); 313 } 314 315 static int __init damon_lru_sort_init(void) 316 { 317 ctx = damon_new_ctx(); 318 if (!ctx) 319 return -ENOMEM; 320 321 if (damon_select_ops(ctx, DAMON_OPS_PADDR)) { 322 damon_destroy_ctx(ctx); 323 return -EINVAL; 324 } 325 326 ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check; 327 ctx->callback.after_aggregation = damon_lru_sort_after_aggregation; 328 329 target = damon_new_target(); 330 if (!target) { 331 damon_destroy_ctx(ctx); 332 return -ENOMEM; 333 } 334 damon_add_target(ctx, target); 335 336 schedule_delayed_work(&damon_lru_sort_timer, 0); 337 338 damon_lru_sort_initialized = true; 339 return 0; 340 } 341 342 module_init(damon_lru_sort_init); 343