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1// SPDX-License-Identifier: GPL-2.02/*3 * DAMON-based page reclamation4 *5 * Author: SeongJae Park <sj@kernel.org>6 */7 8#define pr_fmt(fmt) "damon-reclaim: " 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_reclaim."20 21/*22 * Enable or disable DAMON_RECLAIM.23 *24 * You can enable DAMON_RCLAIM by setting the value of this parameter as ``Y``.25 * Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could26 * do no real monitoring and reclamation due to the watermarks-based activation27 * condition. Refer to below descriptions for the watermarks parameter for28 * this.29 */30static bool enabled __read_mostly;31 32/*33 * Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.34 *35 * Input parameters that updated while DAMON_RECLAIM is running are not applied36 * by default. Once this parameter is set as ``Y``, DAMON_RECLAIM reads values37 * of parametrs except ``enabled`` again. Once the re-reading is done, this38 * parameter is set as ``N``. If invalid parameters are found while the39 * re-reading, DAMON_RECLAIM will be disabled.40 */41static bool commit_inputs __read_mostly;42module_param(commit_inputs, bool, 0600);43 44/*45 * Time threshold for cold memory regions identification in microseconds.46 *47 * If a memory region is not accessed for this or longer time, DAMON_RECLAIM48 * identifies the region as cold, and reclaims. 120 seconds by default.49 */50static unsigned long min_age __read_mostly = 120000000;51module_param(min_age, ulong, 0600);52 53static struct damos_quota damon_reclaim_quota = {54 /* use up to 10 ms time, reclaim up to 128 MiB per 1 sec by default */55 .ms = 10,56 .sz = 128 * 1024 * 1024,57 .reset_interval = 1000,58 /* Within the quota, page out older regions first. */59 .weight_sz = 0,60 .weight_nr_accesses = 0,61 .weight_age = 162};63DEFINE_DAMON_MODULES_DAMOS_QUOTAS(damon_reclaim_quota);64 65/*66 * Desired level of memory pressure-stall time in microseconds.67 *68 * While keeping the caps that set by other quotas, DAMON_RECLAIM automatically69 * increases and decreases the effective level of the quota aiming this level of70 * memory pressure is incurred. System-wide ``some`` memory PSI in microseconds71 * per quota reset interval (``quota_reset_interval_ms``) is collected and72 * compared to this value to see if the aim is satisfied. Value zero means73 * disabling this auto-tuning feature.74 *75 * Disabled by default.76 */77static unsigned long quota_mem_pressure_us __read_mostly;78module_param(quota_mem_pressure_us, ulong, 0600);79 80/*81 * User-specifiable feedback for auto-tuning of the effective quota.82 *83 * While keeping the caps that set by other quotas, DAMON_RECLAIM automatically84 * increases and decreases the effective level of the quota aiming receiving this85 * feedback of value ``10,000`` from the user. DAMON_RECLAIM assumes the feedback86 * value and the quota are positively proportional. Value zero means disabling87 * this auto-tuning feature.88 *89 * Disabled by default.90 *91 */92static unsigned long quota_autotune_feedback __read_mostly;93module_param(quota_autotune_feedback, ulong, 0600);94 95static struct damos_watermarks damon_reclaim_wmarks = {96 .metric = DAMOS_WMARK_FREE_MEM_RATE,97 .interval = 5000000, /* 5 seconds */98 .high = 500, /* 50 percent */99 .mid = 400, /* 40 percent */100 .low = 200, /* 20 percent */101};102DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_reclaim_wmarks);103 104static struct damon_attrs damon_reclaim_mon_attrs = {105 .sample_interval = 5000, /* 5 ms */106 .aggr_interval = 100000, /* 100 ms */107 .ops_update_interval = 0,108 .min_nr_regions = 10,109 .max_nr_regions = 1000,110};111DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_reclaim_mon_attrs);112 113/*114 * Start of the target memory region in physical address.115 *116 * The start physical address of memory region that DAMON_RECLAIM will do work117 * against. By default, biggest System RAM is used as the region.118 */119static unsigned long monitor_region_start __read_mostly;120module_param(monitor_region_start, ulong, 0600);121 122/*123 * End of the target memory region in physical address.124 *125 * The end physical address of memory region that DAMON_RECLAIM will do work126 * against. By default, biggest System RAM is used as the region.127 */128static unsigned long monitor_region_end __read_mostly;129module_param(monitor_region_end, ulong, 0600);130 131/*132 * Skip anonymous pages reclamation.133 *134 * If this parameter is set as ``Y``, DAMON_RECLAIM does not reclaim anonymous135 * pages. By default, ``N``.136 */137static bool skip_anon __read_mostly;138module_param(skip_anon, bool, 0600);139 140/*141 * PID of the DAMON thread142 *143 * If DAMON_RECLAIM is enabled, this becomes the PID of the worker thread.144 * Else, -1.145 */146static int kdamond_pid __read_mostly = -1;147module_param(kdamond_pid, int, 0400);148 149static struct damos_stat damon_reclaim_stat;150DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_reclaim_stat,151 reclaim_tried_regions, reclaimed_regions, quota_exceeds);152 153static struct damon_ctx *ctx;154static struct damon_target *target;155 156static struct damos *damon_reclaim_new_scheme(void)157{158 struct damos_access_pattern pattern = {159 /* Find regions having PAGE_SIZE or larger size */160 .min_sz_region = PAGE_SIZE,161 .max_sz_region = ULONG_MAX,162 /* and not accessed at all */163 .min_nr_accesses = 0,164 .max_nr_accesses = 0,165 /* for min_age or more micro-seconds */166 .min_age_region = min_age /167 damon_reclaim_mon_attrs.aggr_interval,168 .max_age_region = UINT_MAX,169 };170 171 return damon_new_scheme(172 &pattern,173 /* page out those, as soon as found */174 DAMOS_PAGEOUT,175 /* for each aggregation interval */176 0,177 /* under the quota. */178 &damon_reclaim_quota,179 /* (De)activate this according to the watermarks. */180 &damon_reclaim_wmarks,181 NUMA_NO_NODE);182}183 184static int damon_reclaim_apply_parameters(void)185{186 struct damon_ctx *param_ctx;187 struct damon_target *param_target;188 struct damos *scheme;189 struct damos_quota_goal *goal;190 struct damos_filter *filter;191 int err;192 193 err = damon_modules_new_paddr_ctx_target(¶m_ctx, ¶m_target);194 if (err)195 return err;196 197 err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);198 if (err)199 goto out;200 201 err = -ENOMEM;202 scheme = damon_reclaim_new_scheme();203 if (!scheme)204 goto out;205 damon_set_schemes(ctx, &scheme, 1);206 207 if (quota_mem_pressure_us) {208 goal = damos_new_quota_goal(DAMOS_QUOTA_SOME_MEM_PSI_US,209 quota_mem_pressure_us);210 if (!goal)211 goto out;212 damos_add_quota_goal(&scheme->quota, goal);213 }214 215 if (quota_autotune_feedback) {216 goal = damos_new_quota_goal(DAMOS_QUOTA_USER_INPUT, 10000);217 if (!goal)218 goto out;219 goal->current_value = quota_autotune_feedback;220 damos_add_quota_goal(&scheme->quota, goal);221 }222 223 if (skip_anon) {224 filter = damos_new_filter(DAMOS_FILTER_TYPE_ANON, true);225 if (!filter)226 goto out;227 damos_add_filter(scheme, filter);228 }229 230 err = damon_set_region_biggest_system_ram_default(param_target,231 &monitor_region_start,232 &monitor_region_end);233 if (err)234 goto out;235 err = damon_commit_ctx(ctx, param_ctx);236out:237 damon_destroy_ctx(param_ctx);238 return err;239}240 241static int damon_reclaim_turn(bool on)242{243 int err;244 245 if (!on) {246 err = damon_stop(&ctx, 1);247 if (!err)248 kdamond_pid = -1;249 return err;250 }251 252 err = damon_reclaim_apply_parameters();253 if (err)254 return err;255 256 err = damon_start(&ctx, 1, true);257 if (err)258 return err;259 kdamond_pid = ctx->kdamond->pid;260 return 0;261}262 263static int damon_reclaim_enabled_store(const char *val,264 const struct kernel_param *kp)265{266 bool is_enabled = enabled;267 bool enable;268 int err;269 270 err = kstrtobool(val, &enable);271 if (err)272 return err;273 274 if (is_enabled == enable)275 return 0;276 277 /* Called before init function. The function will handle this. */278 if (!ctx)279 goto set_param_out;280 281 err = damon_reclaim_turn(enable);282 if (err)283 return err;284 285set_param_out:286 enabled = enable;287 return err;288}289 290static const struct kernel_param_ops enabled_param_ops = {291 .set = damon_reclaim_enabled_store,292 .get = param_get_bool,293};294 295module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);296MODULE_PARM_DESC(enabled,297 "Enable or disable DAMON_RECLAIM (default: disabled)");298 299static int damon_reclaim_handle_commit_inputs(void)300{301 int err;302 303 if (!commit_inputs)304 return 0;305 306 err = damon_reclaim_apply_parameters();307 commit_inputs = false;308 return err;309}310 311static int damon_reclaim_after_aggregation(struct damon_ctx *c)312{313 struct damos *s;314 315 /* update the stats parameter */316 damon_for_each_scheme(s, c)317 damon_reclaim_stat = s->stat;318 319 return damon_reclaim_handle_commit_inputs();320}321 322static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)323{324 return damon_reclaim_handle_commit_inputs();325}326 327static int __init damon_reclaim_init(void)328{329 int err = damon_modules_new_paddr_ctx_target(&ctx, &target);330 331 if (err)332 return err;333 334 ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;335 ctx->callback.after_aggregation = damon_reclaim_after_aggregation;336 337 /* 'enabled' has set before this function, probably via command line */338 if (enabled)339 err = damon_reclaim_turn(true);340 341 return err;342}343 344module_init(damon_reclaim_init);345