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