WSL2-Linux-Kernel/mm/damon/lru_sort.c

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// SPDX-License-Identifier: GPL-2.0
/*
* DAMON-based LRU-lists Sorting
*
* Author: SeongJae Park <sj@kernel.org>
*/
#define pr_fmt(fmt) "damon-lru-sort: " fmt
#include <linux/damon.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/workqueue.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);
/*
* Limit of time for trying the LRU lists sorting in milliseconds.
*
* DAMON_LRU_SORT tries to use only up to this time within a time window
* (quota_reset_interval_ms) for trying LRU lists sorting. This can be used
* for limiting CPU consumption of DAMON_LRU_SORT. If the value is zero, the
* limit is disabled.
*
* 10 ms by default.
*/
static unsigned long quota_ms __read_mostly = 10;
module_param(quota_ms, ulong, 0600);
/*
* The time quota charge reset interval in milliseconds.
*
* The charge reset interval for the quota of time (quota_ms). That is,
* DAMON_LRU_SORT does not try LRU-lists sorting for more than quota_ms
* milliseconds or quota_sz bytes within quota_reset_interval_ms milliseconds.
*
* 1 second by default.
*/
static unsigned long quota_reset_interval_ms __read_mostly = 1000;
module_param(quota_reset_interval_ms, ulong, 0600);
/*
* The watermarks check time interval in microseconds.
*
* Minimal time to wait before checking the watermarks, when DAMON_LRU_SORT is
* enabled but inactive due to its watermarks rule. 5 seconds by default.
*/
static unsigned long wmarks_interval __read_mostly = 5000000;
module_param(wmarks_interval, ulong, 0600);
/*
* Free memory rate (per thousand) for the high watermark.
*
* If free memory of the system in bytes per thousand bytes is higher than
* this, DAMON_LRU_SORT becomes inactive, so it does nothing but periodically
* checks the watermarks. 200 (20%) by default.
*/
static unsigned long wmarks_high __read_mostly = 200;
module_param(wmarks_high, ulong, 0600);
/*
* Free memory rate (per thousand) for the middle watermark.
*
* If free memory of the system in bytes per thousand bytes is between this and
* the low watermark, DAMON_LRU_SORT becomes active, so starts the monitoring
* and the LRU-lists sorting. 150 (15%) by default.
*/
static unsigned long wmarks_mid __read_mostly = 150;
module_param(wmarks_mid, ulong, 0600);
/*
* Free memory rate (per thousand) for the low watermark.
*
* If free memory of the system in bytes per thousand bytes is lower than this,
* DAMON_LRU_SORT becomes inactive, so it does nothing but periodically checks
* the watermarks. 50 (5%) by default.
*/
static unsigned long wmarks_low __read_mostly = 50;
module_param(wmarks_low, ulong, 0600);
/*
* Sampling interval for the monitoring in microseconds.
*
* The sampling interval of DAMON for the hot/cold memory monitoring. Please
* refer to the DAMON documentation for more detail. 5 ms by default.
*/
static unsigned long sample_interval __read_mostly = 5000;
module_param(sample_interval, ulong, 0600);
/*
* Aggregation interval for the monitoring in microseconds.
*
* The aggregation interval of DAMON for the hot/cold memory monitoring.
* Please refer to the DAMON documentation for more detail. 100 ms by default.
*/
static unsigned long aggr_interval __read_mostly = 100000;
module_param(aggr_interval, ulong, 0600);
/*
* Minimum number of monitoring regions.
*
* The minimal number of monitoring regions of DAMON for the hot/cold memory
* monitoring. This can be used to set lower-bound of the monitoring quality.
* But, setting this too high could result in increased monitoring overhead.
* Please refer to the DAMON documentation for more detail. 10 by default.
*/
static unsigned long min_nr_regions __read_mostly = 10;
module_param(min_nr_regions, ulong, 0600);
/*
* Maximum number of monitoring regions.
*
* The maximum number of monitoring regions of DAMON for the hot/cold memory
* monitoring. This can be used to set upper-bound of the monitoring overhead.
* However, setting this too low could result in bad monitoring quality.
* Please refer to the DAMON documentation for more detail. 1000 by default.
*/
static unsigned long max_nr_regions __read_mostly = 1000;
module_param(max_nr_regions, ulong, 0600);
/*
* 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);
/*
* Number of hot memory regions that tried to be LRU-sorted.
*/
static unsigned long nr_lru_sort_tried_hot_regions __read_mostly;
module_param(nr_lru_sort_tried_hot_regions, ulong, 0400);
/*
* Total bytes of hot memory regions that tried to be LRU-sorted.
*/
static unsigned long bytes_lru_sort_tried_hot_regions __read_mostly;
module_param(bytes_lru_sort_tried_hot_regions, ulong, 0400);
/*
* Number of hot memory regions that successfully be LRU-sorted.
*/
static unsigned long nr_lru_sorted_hot_regions __read_mostly;
module_param(nr_lru_sorted_hot_regions, ulong, 0400);
/*
* Total bytes of hot memory regions that successfully be LRU-sorted.
*/
static unsigned long bytes_lru_sorted_hot_regions __read_mostly;
module_param(bytes_lru_sorted_hot_regions, ulong, 0400);
/*
* Number of times that the time quota limit for hot regions have exceeded
*/
static unsigned long nr_hot_quota_exceeds __read_mostly;
module_param(nr_hot_quota_exceeds, ulong, 0400);
/*
* Number of cold memory regions that tried to be LRU-sorted.
*/
static unsigned long nr_lru_sort_tried_cold_regions __read_mostly;
module_param(nr_lru_sort_tried_cold_regions, ulong, 0400);
/*
* Total bytes of cold memory regions that tried to be LRU-sorted.
*/
static unsigned long bytes_lru_sort_tried_cold_regions __read_mostly;
module_param(bytes_lru_sort_tried_cold_regions, ulong, 0400);
/*
* Number of cold memory regions that successfully be LRU-sorted.
*/
static unsigned long nr_lru_sorted_cold_regions __read_mostly;
module_param(nr_lru_sorted_cold_regions, ulong, 0400);
/*
* Total bytes of cold memory regions that successfully be LRU-sorted.
*/
static unsigned long bytes_lru_sorted_cold_regions __read_mostly;
module_param(bytes_lru_sorted_cold_regions, ulong, 0400);
/*
* Number of times that the time quota limit for cold regions have exceeded
*/
static unsigned long nr_cold_quota_exceeds __read_mostly;
module_param(nr_cold_quota_exceeds, ulong, 0400);
static struct damon_ctx *ctx;
static struct damon_target *target;
struct damon_lru_sort_ram_walk_arg {
unsigned long start;
unsigned long end;
};
static int walk_system_ram(struct resource *res, void *arg)
{
struct damon_lru_sort_ram_walk_arg *a = arg;
if (a->end - a->start < resource_size(res)) {
a->start = res->start;
a->end = res->end;
}
return 0;
}
/*
* Find biggest 'System RAM' resource and store its start and end address in
* @start and @end, respectively. If no System RAM is found, returns false.
*/
static bool get_monitoring_region(unsigned long *start, unsigned long *end)
{
struct damon_lru_sort_ram_walk_arg arg = {};
walk_system_ram_res(0, ULONG_MAX, &arg, walk_system_ram);
if (arg.end <= arg.start)
return false;
*start = arg.start;
*end = arg.end;
return true;
}
/* 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_watermarks wmarks = {
.metric = DAMOS_WMARK_FREE_MEM_RATE,
.interval = wmarks_interval,
.high = wmarks_high,
.mid = wmarks_mid,
.low = wmarks_low,
};
struct damos_quota quota = {
/*
* Do not try LRU-lists sorting of hot pages for more than half
* of quota_ms milliseconds within quota_reset_interval_ms.
*/
.ms = quota_ms / 2,
.sz = 0,
.reset_interval = quota_reset_interval_ms,
/* Within the quota, mark hotter regions accessed first. */
.weight_sz = 0,
.weight_nr_accesses = 1,
.weight_age = 0,
};
struct damos *scheme = damon_new_scheme(
/* Find regions having PAGE_SIZE or larger size */
PAGE_SIZE, ULONG_MAX,
/* and accessed for more than the threshold */
hot_thres, UINT_MAX,
/* no matter its age */
0, UINT_MAX,
/* prioritize those on LRU lists, as soon as found */
DAMOS_LRU_PRIO,
/* under the quota. */
&quota,
/* (De)activate this according to the watermarks. */
&wmarks);
return scheme;
}
/* 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_watermarks wmarks = {
.metric = DAMOS_WMARK_FREE_MEM_RATE,
.interval = wmarks_interval,
.high = wmarks_high,
.mid = wmarks_mid,
.low = wmarks_low,
};
struct damos_quota quota = {
/*
* Do not try LRU-lists sorting of cold pages for more than
* half of quota_ms milliseconds within
* quota_reset_interval_ms.
*/
.ms = quota_ms / 2,
.sz = 0,
.reset_interval = quota_reset_interval_ms,
/* Within the quota, mark colder regions not accessed first. */
.weight_sz = 0,
.weight_nr_accesses = 0,
.weight_age = 1,
};
struct damos *scheme = damon_new_scheme(
/* Find regions having PAGE_SIZE or larger size */
PAGE_SIZE, ULONG_MAX,
/* and not accessed at all */
0, 0,
/* for cold_thres or more micro-seconds, and */
cold_thres, UINT_MAX,
/* mark those as not accessed, as soon as found */
DAMOS_LRU_DEPRIO,
/* under the quota. */
&quota,
/* (De)activate this according to the watermarks. */
&wmarks);
return scheme;
}
static int damon_lru_sort_apply_parameters(void)
{
struct damos *scheme, *next_scheme;
struct damon_addr_range addr_range;
unsigned int hot_thres, cold_thres;
int err = 0;
err = damon_set_attrs(ctx, sample_interval, aggr_interval, 0,
min_nr_regions, max_nr_regions);
if (err)
return err;
/* free previously set schemes */
damon_for_each_scheme_safe(scheme, next_scheme, ctx)
damon_destroy_scheme(scheme);
/* aggr_interval / sample_interval is the maximum nr_accesses */
hot_thres = aggr_interval / sample_interval * hot_thres_access_freq /
1000;
scheme = damon_lru_sort_new_hot_scheme(hot_thres);
if (!scheme)
return -ENOMEM;
damon_add_scheme(ctx, scheme);
cold_thres = cold_min_age / aggr_interval;
scheme = damon_lru_sort_new_cold_scheme(cold_thres);
if (!scheme)
return -ENOMEM;
damon_add_scheme(ctx, scheme);
if (monitor_region_start > monitor_region_end)
return -EINVAL;
if (!monitor_region_start && !monitor_region_end &&
!get_monitoring_region(&monitor_region_start,
&monitor_region_end))
return -EINVAL;
addr_range.start = monitor_region_start;
addr_range.end = monitor_region_end;
return damon_set_regions(target, &addr_range, 1);
}
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 struct delayed_work damon_lru_sort_timer;
static void damon_lru_sort_timer_fn(struct work_struct *work)
{
static bool last_enabled;
bool now_enabled;
now_enabled = enabled;
if (last_enabled != now_enabled) {
if (!damon_lru_sort_turn(now_enabled))
last_enabled = now_enabled;
else
enabled = last_enabled;
}
}
static DECLARE_DELAYED_WORK(damon_lru_sort_timer, damon_lru_sort_timer_fn);
static bool damon_lru_sort_initialized;
static int damon_lru_sort_enabled_store(const char *val,
const struct kernel_param *kp)
{
int rc = param_set_bool(val, kp);
if (rc < 0)
return rc;
if (!damon_lru_sort_initialized)
return rc;
schedule_delayed_work(&damon_lru_sort_timer, 0);
return 0;
}
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) {
nr_lru_sort_tried_hot_regions = s->stat.nr_tried;
bytes_lru_sort_tried_hot_regions = s->stat.sz_tried;
nr_lru_sorted_hot_regions = s->stat.nr_applied;
bytes_lru_sorted_hot_regions = s->stat.sz_applied;
nr_hot_quota_exceeds = s->stat.qt_exceeds;
} else if (s->action == DAMOS_LRU_DEPRIO) {
nr_lru_sort_tried_cold_regions = s->stat.nr_tried;
bytes_lru_sort_tried_cold_regions = s->stat.sz_tried;
nr_lru_sorted_cold_regions = s->stat.nr_applied;
bytes_lru_sorted_cold_regions = s->stat.sz_applied;
nr_cold_quota_exceeds = s->stat.qt_exceeds;
}
}
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)
{
ctx = damon_new_ctx();
if (!ctx)
return -ENOMEM;
if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
damon_destroy_ctx(ctx);
return -EINVAL;
}
ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check;
ctx->callback.after_aggregation = damon_lru_sort_after_aggregation;
target = damon_new_target();
if (!target) {
damon_destroy_ctx(ctx);
return -ENOMEM;
}
damon_add_target(ctx, target);
schedule_delayed_work(&damon_lru_sort_timer, 0);
damon_lru_sort_initialized = true;
return 0;
}
module_init(damon_lru_sort_init);