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 */ 30static 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 */ 41static bool commit_inputs __read_mostly; 42module_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 */ 52static unsigned long hot_thres_access_freq = 500; 53module_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 */ 63static unsigned long cold_min_age __read_mostly = 120000000; 64module_param(cold_min_age, ulong, 0600); 65 66static 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}; 76DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota); 77 78static 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}; 85DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks); 86 87static 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}; 94DEFINE_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 */ 102static unsigned long monitor_region_start __read_mostly; 103module_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 */ 111static unsigned long monitor_region_end __read_mostly; 112module_param(monitor_region_end, ulong, 0600); 113 114/* 115 * PID of the DAMON thread 116 * 117 * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread. 118 * Else, -1. 119 */ 120static int kdamond_pid __read_mostly = -1; 121module_param(kdamond_pid, int, 0400); 122 123static struct damos_stat damon_lru_sort_hot_stat; 124DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat, 125 lru_sort_tried_hot_regions, lru_sorted_hot_regions, 126 hot_quota_exceeds); 127 128static struct damos_stat damon_lru_sort_cold_stat; 129DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, 130 lru_sort_tried_cold_regions, lru_sorted_cold_regions, 131 cold_quota_exceeds); 132 133static struct damos_access_pattern damon_lru_sort_stub_pattern = { 134 /* Find regions having PAGE_SIZE or larger size */ 135 .min_sz_region = PAGE_SIZE, 136 .max_sz_region = ULONG_MAX, 137 /* no matter its access frequency */ 138 .min_nr_accesses = 0, 139 .max_nr_accesses = UINT_MAX, 140 /* no matter its age */ 141 .min_age_region = 0, 142 .max_age_region = UINT_MAX, 143}; 144 145static struct damon_ctx *ctx; 146static struct damon_target *target; 147 148static struct damos *damon_lru_sort_new_scheme( 149 struct damos_access_pattern *pattern, enum damos_action action) 150{ 151 struct damos_quota quota = damon_lru_sort_quota; 152 153 /* Use half of total quota for hot/cold pages sorting */ 154 quota.ms = quota.ms / 2; 155 156 return damon_new_scheme( 157 /* find the pattern, and */ 158 pattern, 159 /* (de)prioritize on LRU-lists */ 160 action, 161 /* for each aggregation interval */ 162 0, 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 */ 170static 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 */ 179static 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 188static void damon_lru_sort_copy_quota_status(struct damos_quota *dst, 189 struct damos_quota *src) 190{ 191 dst->total_charged_sz = src->total_charged_sz; 192 dst->total_charged_ns = src->total_charged_ns; 193 dst->charged_sz = src->charged_sz; 194 dst->charged_from = src->charged_from; 195 dst->charge_target_from = src->charge_target_from; 196 dst->charge_addr_from = src->charge_addr_from; 197} 198 199static int damon_lru_sort_apply_parameters(void) 200{ 201 struct damos *scheme, *hot_scheme, *cold_scheme; 202 struct damos *old_hot_scheme = NULL, *old_cold_scheme = NULL; 203 unsigned int hot_thres, cold_thres; 204 int err = 0; 205 206 err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs); 207 if (err) 208 return err; 209 210 damon_for_each_scheme(scheme, ctx) { 211 if (!old_hot_scheme) { 212 old_hot_scheme = scheme; 213 continue; 214 } 215 old_cold_scheme = scheme; 216 } 217 218 hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) * 219 hot_thres_access_freq / 1000; 220 hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres); 221 if (!hot_scheme) 222 return -ENOMEM; 223 if (old_hot_scheme) 224 damon_lru_sort_copy_quota_status(&hot_scheme->quota, 225 &old_hot_scheme->quota); 226 227 cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval; 228 cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres); 229 if (!cold_scheme) { 230 damon_destroy_scheme(hot_scheme); 231 return -ENOMEM; 232 } 233 if (old_cold_scheme) 234 damon_lru_sort_copy_quota_status(&cold_scheme->quota, 235 &old_cold_scheme->quota); 236 237 damon_set_schemes(ctx, &hot_scheme, 1); 238 damon_add_scheme(ctx, cold_scheme); 239 240 return damon_set_region_biggest_system_ram_default(target, 241 &monitor_region_start, 242 &monitor_region_end); 243} 244 245static int damon_lru_sort_turn(bool on) 246{ 247 int err; 248 249 if (!on) { 250 err = damon_stop(&ctx, 1); 251 if (!err) 252 kdamond_pid = -1; 253 return err; 254 } 255 256 err = damon_lru_sort_apply_parameters(); 257 if (err) 258 return err; 259 260 err = damon_start(&ctx, 1, true); 261 if (err) 262 return err; 263 kdamond_pid = ctx->kdamond->pid; 264 return 0; 265} 266 267static int damon_lru_sort_enabled_store(const char *val, 268 const struct kernel_param *kp) 269{ 270 bool is_enabled = enabled; 271 bool enable; 272 int err; 273 274 err = kstrtobool(val, &enable); 275 if (err) 276 return err; 277 278 if (is_enabled == enable) 279 return 0; 280 281 /* Called before init function. The function will handle this. */ 282 if (!ctx) 283 goto set_param_out; 284 285 err = damon_lru_sort_turn(enable); 286 if (err) 287 return err; 288 289set_param_out: 290 enabled = enable; 291 return err; 292} 293 294static const struct kernel_param_ops enabled_param_ops = { 295 .set = damon_lru_sort_enabled_store, 296 .get = param_get_bool, 297}; 298 299module_param_cb(enabled, &enabled_param_ops, &enabled, 0600); 300MODULE_PARM_DESC(enabled, 301 "Enable or disable DAMON_LRU_SORT (default: disabled)"); 302 303static int damon_lru_sort_handle_commit_inputs(void) 304{ 305 int err; 306 307 if (!commit_inputs) 308 return 0; 309 310 err = damon_lru_sort_apply_parameters(); 311 commit_inputs = false; 312 return err; 313} 314 315static int damon_lru_sort_after_aggregation(struct damon_ctx *c) 316{ 317 struct damos *s; 318 319 /* update the stats parameter */ 320 damon_for_each_scheme(s, c) { 321 if (s->action == DAMOS_LRU_PRIO) 322 damon_lru_sort_hot_stat = s->stat; 323 else if (s->action == DAMOS_LRU_DEPRIO) 324 damon_lru_sort_cold_stat = s->stat; 325 } 326 327 return damon_lru_sort_handle_commit_inputs(); 328} 329 330static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c) 331{ 332 return damon_lru_sort_handle_commit_inputs(); 333} 334 335static int __init damon_lru_sort_init(void) 336{ 337 int err = damon_modules_new_paddr_ctx_target(&ctx, &target); 338 339 if (err) 340 return err; 341 342 ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check; 343 ctx->callback.after_aggregation = damon_lru_sort_after_aggregation; 344 345 /* 'enabled' has set before this function, probably via command line */ 346 if (enabled) 347 err = damon_lru_sort_turn(true); 348 349 return err; 350} 351 352module_init(damon_lru_sort_init); 353