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1// SPDX-License-Identifier: GPL-2.02/*3 * DAMON-based LRU-lists Sorting4 *5 * Author: SeongJae Park <sj@kernel.org>6 */7 8#define pr_fmt(fmt) "damon-lru-sort: " fmt9 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_PREFIX17#undef MODULE_PARAM_PREFIX18#endif19#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 as25 * ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that26 * DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the27 * watermarks-based activation condition. Refer to below descriptions for the28 * 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 not36 * applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT37 * reads values of parametrs except ``enabled`` again. Once the re-reading is38 * done, this parameter is set as ``N``. If invalid parameters are found while39 * 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 the49 * LRU list, so that it could not be reclaimed under memory pressure. 50% by50 * 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_SORT59 * identifies the region as cold, and mark it as unaccessed on the LRU list, so60 * that it could be reclaimed first under memory pressure. 120 seconds by61 * 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 work100 * 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 work109 * 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 thread116 *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 NUMA_NO_NODE);168}169 170/* Create a DAMON-based operation scheme for hot memory regions */171static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres)172{173 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern;174 175 pattern.min_nr_accesses = hot_thres;176 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO);177}178 179/* Create a DAMON-based operation scheme for cold memory regions */180static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres)181{182 struct damos_access_pattern pattern = damon_lru_sort_stub_pattern;183 184 pattern.max_nr_accesses = 0;185 pattern.min_age_region = cold_thres;186 return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO);187}188 189static int damon_lru_sort_apply_parameters(void)190{191 struct damon_ctx *param_ctx;192 struct damon_target *param_target;193 struct damos *hot_scheme, *cold_scheme;194 unsigned int hot_thres, cold_thres;195 int err;196 197 err = damon_modules_new_paddr_ctx_target(¶m_ctx, ¶m_target);198 if (err)199 return err;200 201 err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs);202 if (err)203 goto out;204 205 err = -ENOMEM;206 hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) *207 hot_thres_access_freq / 1000;208 hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres);209 if (!hot_scheme)210 goto out;211 212 cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval;213 cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres);214 if (!cold_scheme) {215 damon_destroy_scheme(hot_scheme);216 goto out;217 }218 219 damon_set_schemes(param_ctx, &hot_scheme, 1);220 damon_add_scheme(param_ctx, cold_scheme);221 222 err = damon_set_region_biggest_system_ram_default(param_target,223 &monitor_region_start,224 &monitor_region_end);225 if (err)226 goto out;227 err = damon_commit_ctx(ctx, param_ctx);228out:229 damon_destroy_ctx(param_ctx);230 return err;231}232 233static int damon_lru_sort_turn(bool on)234{235 int err;236 237 if (!on) {238 err = damon_stop(&ctx, 1);239 if (!err)240 kdamond_pid = -1;241 return err;242 }243 244 err = damon_lru_sort_apply_parameters();245 if (err)246 return err;247 248 err = damon_start(&ctx, 1, true);249 if (err)250 return err;251 kdamond_pid = ctx->kdamond->pid;252 return 0;253}254 255static int damon_lru_sort_enabled_store(const char *val,256 const struct kernel_param *kp)257{258 bool is_enabled = enabled;259 bool enable;260 int err;261 262 err = kstrtobool(val, &enable);263 if (err)264 return err;265 266 if (is_enabled == enable)267 return 0;268 269 /* Called before init function. The function will handle this. */270 if (!ctx)271 goto set_param_out;272 273 err = damon_lru_sort_turn(enable);274 if (err)275 return err;276 277set_param_out:278 enabled = enable;279 return err;280}281 282static const struct kernel_param_ops enabled_param_ops = {283 .set = damon_lru_sort_enabled_store,284 .get = param_get_bool,285};286 287module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);288MODULE_PARM_DESC(enabled,289 "Enable or disable DAMON_LRU_SORT (default: disabled)");290 291static int damon_lru_sort_handle_commit_inputs(void)292{293 int err;294 295 if (!commit_inputs)296 return 0;297 298 err = damon_lru_sort_apply_parameters();299 commit_inputs = false;300 return err;301}302 303static int damon_lru_sort_after_aggregation(struct damon_ctx *c)304{305 struct damos *s;306 307 /* update the stats parameter */308 damon_for_each_scheme(s, c) {309 if (s->action == DAMOS_LRU_PRIO)310 damon_lru_sort_hot_stat = s->stat;311 else if (s->action == DAMOS_LRU_DEPRIO)312 damon_lru_sort_cold_stat = s->stat;313 }314 315 return damon_lru_sort_handle_commit_inputs();316}317 318static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c)319{320 return damon_lru_sort_handle_commit_inputs();321}322 323static int __init damon_lru_sort_init(void)324{325 int err = damon_modules_new_paddr_ctx_target(&ctx, &target);326 327 if (err)328 return err;329 330 ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check;331 ctx->callback.after_aggregation = damon_lru_sort_after_aggregation;332 333 /* 'enabled' has set before this function, probably via command line */334 if (enabled)335 err = damon_lru_sort_turn(true);336 337 return err;338}339 340module_init(damon_lru_sort_init);341