// SPDX-License-Identifier: GPL-2.0 /* * DAMON-based LRU-lists Sorting * * Author: SeongJae Park */ #define pr_fmt(fmt) "damon-lru-sort: " fmt #include #include #include #include "modules-common.h" #ifdef MODULE_PARAM_PREFIX #undef MODULE_PARAM_PREFIX #endif #define MODULE_PARAM_PREFIX "damon_lru_sort." /* * Enable or disable DAMON_LRU_SORT. * * You can enable DAMON_LRU_SORT by setting the value of this parameter as * ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that * DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the * watermarks-based activation condition. Refer to below descriptions for the * watermarks parameter for this. */ static bool enabled __read_mostly; /* * Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``. * * Input parameters that updated while DAMON_LRU_SORT is running are not * applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT * reads values of parametrs except ``enabled`` again. Once the re-reading is * done, this parameter is set as ``N``. If invalid parameters are found while * the re-reading, DAMON_LRU_SORT will be disabled. */ static bool commit_inputs __read_mostly; module_param(commit_inputs, bool, 0600); /* * Access frequency threshold for hot memory regions identification in permil. * * If a memory region is accessed in frequency of this or higher, * DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the * LRU list, so that it could not be reclaimed under memory pressure. 50% by * default. */ static unsigned long hot_thres_access_freq = 500; module_param(hot_thres_access_freq, ulong, 0600); /* * Time threshold for cold memory regions identification in microseconds. * * If a memory region is not accessed for this or longer time, DAMON_LRU_SORT * identifies the region as cold, and mark it as unaccessed on the LRU list, so * that it could be reclaimed first under memory pressure. 120 seconds by * default. */ static unsigned long cold_min_age __read_mostly = 120000000; module_param(cold_min_age, ulong, 0600); static struct damos_quota damon_lru_sort_quota = { /* Use up to 10 ms per 1 sec, by default */ .ms = 10, .sz = 0, .reset_interval = 1000, /* Within the quota, mark hotter regions accessed first. */ .weight_sz = 0, .weight_nr_accesses = 1, .weight_age = 0, }; DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota); static struct damos_watermarks damon_lru_sort_wmarks = { .metric = DAMOS_WMARK_FREE_MEM_RATE, .interval = 5000000, /* 5 seconds */ .high = 200, /* 20 percent */ .mid = 150, /* 15 percent */ .low = 50, /* 5 percent */ }; DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks); static struct damon_attrs damon_lru_sort_mon_attrs = { .sample_interval = 5000, /* 5 ms */ .aggr_interval = 100000, /* 100 ms */ .ops_update_interval = 0, .min_nr_regions = 10, .max_nr_regions = 1000, }; DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_lru_sort_mon_attrs); /* * Start of the target memory region in physical address. * * The start physical address of memory region that DAMON_LRU_SORT will do work * against. By default, biggest System RAM is used as the region. */ static unsigned long monitor_region_start __read_mostly; module_param(monitor_region_start, ulong, 0600); /* * End of the target memory region in physical address. * * The end physical address of memory region that DAMON_LRU_SORT will do work * against. By default, biggest System RAM is used as the region. */ static unsigned long monitor_region_end __read_mostly; module_param(monitor_region_end, ulong, 0600); /* * PID of the DAMON thread * * If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread. * Else, -1. */ static int kdamond_pid __read_mostly = -1; module_param(kdamond_pid, int, 0400); static struct damos_stat damon_lru_sort_hot_stat; DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat, lru_sort_tried_hot_regions, lru_sorted_hot_regions, hot_quota_exceeds); static struct damos_stat damon_lru_sort_cold_stat; DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat, lru_sort_tried_cold_regions, lru_sorted_cold_regions, cold_quota_exceeds); static struct damos_access_pattern damon_lru_sort_stub_pattern = { /* Find regions having PAGE_SIZE or larger size */ .min_sz_region = PAGE_SIZE, .max_sz_region = ULONG_MAX, /* no matter its access frequency */ .min_nr_accesses = 0, .max_nr_accesses = UINT_MAX, /* no matter its age */ .min_age_region = 0, .max_age_region = UINT_MAX, }; static struct damon_ctx *ctx; static struct damon_target *target; static struct damos *damon_lru_sort_new_scheme( struct damos_access_pattern *pattern, enum damos_action action) { struct damos_quota quota = damon_lru_sort_quota; /* Use half of total quota for hot/cold pages sorting */ quota.ms = quota.ms / 2; return damon_new_scheme( /* find the pattern, and */ pattern, /* (de)prioritize on LRU-lists */ action, /* for each aggregation interval */ 0, /* under the quota. */ "a, /* (De)activate this according to the watermarks. */ &damon_lru_sort_wmarks); } /* Create a DAMON-based operation scheme for hot memory regions */ static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres) { struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; pattern.min_nr_accesses = hot_thres; return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO); } /* Create a DAMON-based operation scheme for cold memory regions */ static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres) { struct damos_access_pattern pattern = damon_lru_sort_stub_pattern; pattern.max_nr_accesses = 0; pattern.min_age_region = cold_thres; return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO); } static void damon_lru_sort_copy_quota_status(struct damos_quota *dst, struct damos_quota *src) { dst->total_charged_sz = src->total_charged_sz; dst->total_charged_ns = src->total_charged_ns; dst->charged_sz = src->charged_sz; dst->charged_from = src->charged_from; dst->charge_target_from = src->charge_target_from; dst->charge_addr_from = src->charge_addr_from; } static int damon_lru_sort_apply_parameters(void) { struct damos *scheme, *hot_scheme, *cold_scheme; struct damos *old_hot_scheme = NULL, *old_cold_scheme = NULL; unsigned int hot_thres, cold_thres; int err = 0; err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs); if (err) return err; damon_for_each_scheme(scheme, ctx) { if (!old_hot_scheme) { old_hot_scheme = scheme; continue; } old_cold_scheme = scheme; } hot_thres = damon_max_nr_accesses(&damon_lru_sort_mon_attrs) * hot_thres_access_freq / 1000; hot_scheme = damon_lru_sort_new_hot_scheme(hot_thres); if (!hot_scheme) return -ENOMEM; if (old_hot_scheme) damon_lru_sort_copy_quota_status(&hot_scheme->quota, &old_hot_scheme->quota); cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval; cold_scheme = damon_lru_sort_new_cold_scheme(cold_thres); if (!cold_scheme) { damon_destroy_scheme(hot_scheme); return -ENOMEM; } if (old_cold_scheme) damon_lru_sort_copy_quota_status(&cold_scheme->quota, &old_cold_scheme->quota); damon_set_schemes(ctx, &hot_scheme, 1); damon_add_scheme(ctx, cold_scheme); return damon_set_region_biggest_system_ram_default(target, &monitor_region_start, &monitor_region_end); } static int damon_lru_sort_turn(bool on) { int err; if (!on) { err = damon_stop(&ctx, 1); if (!err) kdamond_pid = -1; return err; } err = damon_lru_sort_apply_parameters(); if (err) return err; err = damon_start(&ctx, 1, true); if (err) return err; kdamond_pid = ctx->kdamond->pid; return 0; } static int damon_lru_sort_enabled_store(const char *val, const struct kernel_param *kp) { bool is_enabled = enabled; bool enable; int err; err = kstrtobool(val, &enable); if (err) return err; if (is_enabled == enable) return 0; /* Called before init function. The function will handle this. */ if (!ctx) goto set_param_out; err = damon_lru_sort_turn(enable); if (err) return err; set_param_out: enabled = enable; return err; } static const struct kernel_param_ops enabled_param_ops = { .set = damon_lru_sort_enabled_store, .get = param_get_bool, }; module_param_cb(enabled, &enabled_param_ops, &enabled, 0600); MODULE_PARM_DESC(enabled, "Enable or disable DAMON_LRU_SORT (default: disabled)"); static int damon_lru_sort_handle_commit_inputs(void) { int err; if (!commit_inputs) return 0; err = damon_lru_sort_apply_parameters(); commit_inputs = false; return err; } static int damon_lru_sort_after_aggregation(struct damon_ctx *c) { struct damos *s; /* update the stats parameter */ damon_for_each_scheme(s, c) { if (s->action == DAMOS_LRU_PRIO) damon_lru_sort_hot_stat = s->stat; else if (s->action == DAMOS_LRU_DEPRIO) damon_lru_sort_cold_stat = s->stat; } return damon_lru_sort_handle_commit_inputs(); } static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c) { return damon_lru_sort_handle_commit_inputs(); } static int __init damon_lru_sort_init(void) { int err = damon_modules_new_paddr_ctx_target(&ctx, &target); if (err) return err; ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check; ctx->callback.after_aggregation = damon_lru_sort_after_aggregation; /* 'enabled' has set before this function, probably via command line */ if (enabled) err = damon_lru_sort_turn(true); return err; } module_init(damon_lru_sort_init);