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![SeongJae Park](/assets/img/avatar_default.png)
Support the PSI-driven quota self-tuning from DAMON_RECLAIM by introducing yet another parameter, 'quota_mem_pressure_us'. Users can set the desired amount of memory pressure stall time per each quota reset interval using the parameter. Then DAMON_RECLAIM monitor the memory pressure stall time, specifically system-wide memory 'some' PSI value that increased during the given time interval, and self-tune the quota using the DAMOS core logic. Link: https://lkml.kernel.org/r/20240219194431.159606-20-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
356 lines
9.4 KiB
C
356 lines
9.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* DAMON-based page reclamation
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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-reclaim: " 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_reclaim."
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/*
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* Enable or disable DAMON_RECLAIM.
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*
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* You can enable DAMON_RCLAIM by setting the value of this parameter as ``Y``.
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* Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could
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* do no real monitoring and reclamation due to the watermarks-based activation
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* condition. Refer to below descriptions for the watermarks parameter for
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* this.
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*/
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static bool enabled __read_mostly;
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/*
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* Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.
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*
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* Input parameters that updated while DAMON_RECLAIM is running are not applied
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* by default. Once this parameter is set as ``Y``, DAMON_RECLAIM reads values
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* of parametrs except ``enabled`` again. Once the re-reading is done, this
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* parameter is set as ``N``. If invalid parameters are found while the
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* re-reading, DAMON_RECLAIM 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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* 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_RECLAIM
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* identifies the region as cold, and reclaims. 120 seconds by default.
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*/
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static unsigned long min_age __read_mostly = 120000000;
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module_param(min_age, ulong, 0600);
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static struct damos_quota damon_reclaim_quota = {
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/* use up to 10 ms time, reclaim up to 128 MiB per 1 sec by default */
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.ms = 10,
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.sz = 128 * 1024 * 1024,
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.reset_interval = 1000,
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/* Within the quota, page out older regions first. */
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.weight_sz = 0,
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.weight_nr_accesses = 0,
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.weight_age = 1
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};
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DEFINE_DAMON_MODULES_DAMOS_QUOTAS(damon_reclaim_quota);
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/*
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* Desired level of memory pressure-stall time in microseconds.
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*
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* While keeping the caps that set by other quotas, DAMON_RECLAIM automatically
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* increases and decreases the effective level of the quota aiming this level of
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* memory pressure is incurred. System-wide ``some`` memory PSI in microseconds
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* per quota reset interval (``quota_reset_interval_ms``) is collected and
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* compared to this value to see if the aim is satisfied. Value zero means
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* disabling this auto-tuning feature.
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*
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* Disabled by default.
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*/
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static unsigned long quota_mem_pressure_us __read_mostly;
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module_param(quota_mem_pressure_us, ulong, 0600);
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/*
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* User-specifiable feedback for auto-tuning of the effective quota.
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*
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* While keeping the caps that set by other quotas, DAMON_RECLAIM automatically
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* increases and decreases the effective level of the quota aiming receiving this
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* feedback of value ``10,000`` from the user. DAMON_RECLAIM assumes the feedback
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* value and the quota are positively proportional. Value zero means disabling
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* this auto-tuning feature.
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*
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* Disabled by default.
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*
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*/
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static unsigned long quota_autotune_feedback __read_mostly;
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module_param(quota_autotune_feedback, ulong, 0600);
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static struct damos_watermarks damon_reclaim_wmarks = {
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.metric = DAMOS_WMARK_FREE_MEM_RATE,
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.interval = 5000000, /* 5 seconds */
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.high = 500, /* 50 percent */
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.mid = 400, /* 40 percent */
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.low = 200, /* 20 percent */
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};
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DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_reclaim_wmarks);
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static struct damon_attrs damon_reclaim_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_reclaim_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_RECLAIM 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_RECLAIM 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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* Skip anonymous pages reclamation.
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*
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* If this parameter is set as ``Y``, DAMON_RECLAIM does not reclaim anonymous
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* pages. By default, ``N``.
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*/
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static bool skip_anon __read_mostly;
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module_param(skip_anon, bool, 0600);
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/*
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* PID of the DAMON thread
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*
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* If DAMON_RECLAIM 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_reclaim_stat;
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DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_reclaim_stat,
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reclaim_tried_regions, reclaimed_regions, quota_exceeds);
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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_reclaim_new_scheme(void)
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{
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struct damos_access_pattern 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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/* and not accessed at all */
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.min_nr_accesses = 0,
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.max_nr_accesses = 0,
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/* for min_age or more micro-seconds */
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.min_age_region = min_age /
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damon_reclaim_mon_attrs.aggr_interval,
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.max_age_region = UINT_MAX,
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};
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return damon_new_scheme(
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&pattern,
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/* page out those, as soon as found */
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DAMOS_PAGEOUT,
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/* for each aggregation interval */
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0,
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/* under the quota. */
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&damon_reclaim_quota,
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/* (De)activate this according to the watermarks. */
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&damon_reclaim_wmarks);
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}
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static void damon_reclaim_copy_quota_status(struct damos_quota *dst,
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struct damos_quota *src)
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{
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dst->total_charged_sz = src->total_charged_sz;
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dst->total_charged_ns = src->total_charged_ns;
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dst->charged_sz = src->charged_sz;
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dst->charged_from = src->charged_from;
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dst->charge_target_from = src->charge_target_from;
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dst->charge_addr_from = src->charge_addr_from;
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dst->esz_bp = src->esz_bp;
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}
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static int damon_reclaim_apply_parameters(void)
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{
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struct damos *scheme, *old_scheme;
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struct damos_quota_goal *goal;
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struct damos_filter *filter;
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int err = 0;
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err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
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if (err)
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return err;
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/* Will be freed by next 'damon_set_schemes()' below */
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scheme = damon_reclaim_new_scheme();
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if (!scheme)
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return -ENOMEM;
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if (!list_empty(&ctx->schemes)) {
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damon_for_each_scheme(old_scheme, ctx)
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damon_reclaim_copy_quota_status(&scheme->quota,
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&old_scheme->quota);
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}
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if (quota_mem_pressure_us) {
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goal = damos_new_quota_goal(DAMOS_QUOTA_SOME_MEM_PSI_US,
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quota_mem_pressure_us);
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if (!goal) {
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damon_destroy_scheme(scheme);
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return -ENOMEM;
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}
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damos_add_quota_goal(&scheme->quota, goal);
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}
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if (quota_autotune_feedback) {
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goal = damos_new_quota_goal(DAMOS_QUOTA_USER_INPUT, 10000);
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if (!goal) {
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damon_destroy_scheme(scheme);
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return -ENOMEM;
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}
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goal->current_value = quota_autotune_feedback;
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damos_add_quota_goal(&scheme->quota, goal);
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}
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if (skip_anon) {
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filter = damos_new_filter(DAMOS_FILTER_TYPE_ANON, true);
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if (!filter) {
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/* Will be freed by next 'damon_set_schemes()' below */
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damon_destroy_scheme(scheme);
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return -ENOMEM;
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}
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damos_add_filter(scheme, filter);
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}
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damon_set_schemes(ctx, &scheme, 1);
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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_reclaim_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_reclaim_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_reclaim_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_reclaim_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_reclaim_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_RECLAIM (default: disabled)");
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static int damon_reclaim_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_reclaim_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_reclaim_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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damon_reclaim_stat = s->stat;
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return damon_reclaim_handle_commit_inputs();
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}
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static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)
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{
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return damon_reclaim_handle_commit_inputs();
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}
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static int __init damon_reclaim_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_reclaim_after_wmarks_check;
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ctx->callback.after_aggregation = damon_reclaim_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_reclaim_turn(true);
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return err;
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}
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module_init(damon_reclaim_init);
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