mm/damon/reclaim.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * DAMON-based page reclamation
  *
  * Author: SeongJae Park <sj@kernel.org>
  */

 #define pr_fmt(fmt) "damon-reclaim: " fmt

 #include <linux/damon.h>
 #include <linux/kstrtox.h>
 #include <linux/module.h>

 #include "modules-common.h"

 #ifdef MODULE_PARAM_PREFIX
 #undef MODULE_PARAM_PREFIX
 #endif
 #define MODULE_PARAM_PREFIX "damon_reclaim."

 /*
  * Enable or disable DAMON_RECLAIM.
  *
  * You can enable DAMON_RCLAIM by setting the value of this parameter as ``Y``.
  * Setting it as ``N`` disables DAMON_RECLAIM.  Note that DAMON_RECLAIM could
  * do no real monitoring and reclamation due to the watermarks-based activation
  * condition.  Refer to below descriptions for the watermarks parameter for
  * this.
  */
 static bool enabled __read_mostly;

 /*
  * Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.
  *
  * Input parameters that updated while DAMON_RECLAIM is running are not applied
  * by default.  Once this parameter is set as ``Y``, DAMON_RECLAIM 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_RECLAIM will be disabled.
  */
 static bool commit_inputs __read_mostly;
 module_param(commit_inputs, bool, 0600);

 /*
  * Time threshold for cold memory regions identification in microseconds.
  *
  * If a memory region is not accessed for this or longer time, DAMON_RECLAIM
  * identifies the region as cold, and reclaims.  120 seconds by default.
  */
 static unsigned long min_age __read_mostly = 120000000;
 module_param(min_age, ulong, 0600);

 static struct damos_quota damon_reclaim_quota = {
 	/* use up to 10 ms time, reclaim up to 128 MiB per 1 sec by default */
 	.ms = 10,
 	.sz = 128 * 1024 * 1024,
 	.reset_interval = 1000,
 	/* Within the quota, page out older regions first. */
 	.weight_sz = 0,
 	.weight_nr_accesses = 0,
 	.weight_age = 1
 };
 DEFINE_DAMON_MODULES_DAMOS_QUOTAS(damon_reclaim_quota);

 static struct damos_watermarks damon_reclaim_wmarks = {
 	.metric = DAMOS_WMARK_FREE_MEM_RATE,
 	.interval = 5000000,	/* 5 seconds */
 	.high = 500,		/* 50 percent */
 	.mid = 400,		/* 40 percent */
 	.low = 200,		/* 20 percent */
 };
 DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_reclaim_wmarks);

 static struct damon_attrs damon_reclaim_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_reclaim_mon_attrs);

 /*
  * Start of the target memory region in physical address.
  *
  * The start physical address of memory region that DAMON_RECLAIM 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_RECLAIM 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_RECLAIM 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_reclaim_stat;
 DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_reclaim_stat,
 		reclaim_tried_regions, reclaimed_regions, quota_exceeds);

 static struct damon_ctx *ctx;
 static struct damon_target *target;

 static struct damos *damon_reclaim_new_scheme(void)
 {
 	struct damos_access_pattern pattern = {
 		/* Find regions having PAGE_SIZE or larger size */
 		.min_sz_region = PAGE_SIZE,
 		.max_sz_region = ULONG_MAX,
 		/* and not accessed at all */
 		.min_nr_accesses = 0,
 		.max_nr_accesses = 0,
 		/* for min_age or more micro-seconds */
 		.min_age_region = min_age /
 			damon_reclaim_mon_attrs.aggr_interval,
 		.max_age_region = UINT_MAX,
 	};

 	return damon_new_scheme(
 			&pattern,
 			/* page out those, as soon as found */
 			DAMOS_PAGEOUT,
 			/* under the quota. */
 			&damon_reclaim_quota,
 			/* (De)activate this according to the watermarks. */
 			&damon_reclaim_wmarks);
 }

 static int damon_reclaim_apply_parameters(void)
 {
 	struct damos *scheme;
 	int err = 0;

 	err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
 	if (err)
 		return err;

 	/* Will be freed by next 'damon_set_schemes()' below */
 	scheme = damon_reclaim_new_scheme();
 	if (!scheme)
 		return -ENOMEM;
 	damon_set_schemes(ctx, &scheme, 1);

 	return damon_set_region_biggest_system_ram_default(target,
 					&monitor_region_start,
 					&monitor_region_end);
 }

 static int damon_reclaim_turn(bool on)
 {
 	int err;

 	if (!on) {
 		err = damon_stop(&ctx, 1);
 		if (!err)
 			kdamond_pid = -1;
 		return err;
 	}

 	err = damon_reclaim_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_reclaim_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_reclaim_turn(enable);
 	if (err)
 		return err;

 set_param_out:
 	enabled = enable;
 	return err;
 }

 static const struct kernel_param_ops enabled_param_ops = {
 	.set = damon_reclaim_enabled_store,
 	.get = param_get_bool,
 };

 module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
 MODULE_PARM_DESC(enabled,
 	"Enable or disable DAMON_RECLAIM (default: disabled)");

 static int damon_reclaim_handle_commit_inputs(void)
 {
 	int err;

 	if (!commit_inputs)
 		return 0;

 	err = damon_reclaim_apply_parameters();
 	commit_inputs = false;
 	return err;
 }

 static int damon_reclaim_after_aggregation(struct damon_ctx *c)
 {
 	struct damos *s;

 	/* update the stats parameter */
 	damon_for_each_scheme(s, c)
 		damon_reclaim_stat = s->stat;

 	return damon_reclaim_handle_commit_inputs();
 }

 static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)
 {
 	return damon_reclaim_handle_commit_inputs();
 }

 static int __init damon_reclaim_init(void)
 {
 	int err = damon_modules_new_paddr_ctx_target(&ctx, &target);

 	if (err)
 		return err;

 	ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;
 	ctx->callback.after_aggregation = damon_reclaim_after_aggregation;

 	/* 'enabled' has set before this function, probably via command line */
 	if (enabled)
 		err = damon_reclaim_turn(true);

 	return err;
 }

 module_init(damon_reclaim_init);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* DAMON-based page reclamation
	*
	* Author: SeongJae Park <sj@kernel.org>
	*/

	#define pr_fmt(fmt) "damon-reclaim: " fmt

	#include <linux/damon.h>
	#include <linux/kstrtox.h>
	#include <linux/module.h>

	#include "modules-common.h"

	#ifdef MODULE_PARAM_PREFIX
	#undef MODULE_PARAM_PREFIX
	#endif
	#define MODULE_PARAM_PREFIX "damon_reclaim."

	/*
	* Enable or disable DAMON_RECLAIM.
	*
	* You can enable DAMON_RCLAIM by setting the value of this parameter as ``Y``.
	* Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could
	* do no real monitoring and reclamation due to the watermarks-based activation
	* condition. Refer to below descriptions for the watermarks parameter for
	* this.
	*/
	static bool enabled __read_mostly;

	/*
	* Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.
	*
	* Input parameters that updated while DAMON_RECLAIM is running are not applied
	* by default. Once this parameter is set as ``Y``, DAMON_RECLAIM 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_RECLAIM will be disabled.
	*/
	static bool commit_inputs __read_mostly;
	module_param(commit_inputs, bool, 0600);

	/*
	* Time threshold for cold memory regions identification in microseconds.
	*
	* If a memory region is not accessed for this or longer time, DAMON_RECLAIM
	* identifies the region as cold, and reclaims. 120 seconds by default.
	*/
	static unsigned long min_age __read_mostly = 120000000;
	module_param(min_age, ulong, 0600);

	static struct damos_quota damon_reclaim_quota = {
	/* use up to 10 ms time, reclaim up to 128 MiB per 1 sec by default */
	.ms = 10,
	.sz = 128 * 1024 * 1024,
	.reset_interval = 1000,
	/* Within the quota, page out older regions first. */
	.weight_sz = 0,
	.weight_nr_accesses = 0,
	.weight_age = 1
	};
	DEFINE_DAMON_MODULES_DAMOS_QUOTAS(damon_reclaim_quota);

	static struct damos_watermarks damon_reclaim_wmarks = {
	.metric = DAMOS_WMARK_FREE_MEM_RATE,
	.interval = 5000000, /* 5 seconds */
	.high = 500, /* 50 percent */
	.mid = 400, /* 40 percent */
	.low = 200, /* 20 percent */
	};
	DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_reclaim_wmarks);

	static struct damon_attrs damon_reclaim_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_reclaim_mon_attrs);

	/*
	* Start of the target memory region in physical address.
	*
	* The start physical address of memory region that DAMON_RECLAIM 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_RECLAIM 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_RECLAIM 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_reclaim_stat;
	DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_reclaim_stat,
	reclaim_tried_regions, reclaimed_regions, quota_exceeds);

	static struct damon_ctx *ctx;
	static struct damon_target *target;

	static struct damos *damon_reclaim_new_scheme(void)
	{
	struct damos_access_pattern pattern = {
	/* Find regions having PAGE_SIZE or larger size */
	.min_sz_region = PAGE_SIZE,
	.max_sz_region = ULONG_MAX,
	/* and not accessed at all */
	.min_nr_accesses = 0,
	.max_nr_accesses = 0,
	/* for min_age or more micro-seconds */
	.min_age_region = min_age /
	damon_reclaim_mon_attrs.aggr_interval,
	.max_age_region = UINT_MAX,
	};

	return damon_new_scheme(
	&pattern,
	/* page out those, as soon as found */
	DAMOS_PAGEOUT,
	/* under the quota. */
	&damon_reclaim_quota,
	/* (De)activate this according to the watermarks. */
	&damon_reclaim_wmarks);
	}

	static int damon_reclaim_apply_parameters(void)
	{
	struct damos *scheme;
	int err = 0;

	err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
	if (err)
	return err;

	/* Will be freed by next 'damon_set_schemes()' below */
	scheme = damon_reclaim_new_scheme();
	if (!scheme)
	return -ENOMEM;
	damon_set_schemes(ctx, &scheme, 1);

	return damon_set_region_biggest_system_ram_default(target,
	&monitor_region_start,
	&monitor_region_end);
	}

	static int damon_reclaim_turn(bool on)
	{
	int err;

	if (!on) {
	err = damon_stop(&ctx, 1);
	if (!err)
	kdamond_pid = -1;
	return err;
	}

	err = damon_reclaim_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_reclaim_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_reclaim_turn(enable);
	if (err)
	return err;

	set_param_out:
	enabled = enable;
	return err;
	}

	static const struct kernel_param_ops enabled_param_ops = {
	.set = damon_reclaim_enabled_store,
	.get = param_get_bool,
	};

	module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
	MODULE_PARM_DESC(enabled,
	"Enable or disable DAMON_RECLAIM (default: disabled)");

	static int damon_reclaim_handle_commit_inputs(void)
	{
	int err;

	if (!commit_inputs)
	return 0;

	err = damon_reclaim_apply_parameters();
	commit_inputs = false;
	return err;
	}

	static int damon_reclaim_after_aggregation(struct damon_ctx *c)
	{
	struct damos *s;

	/* update the stats parameter */
	damon_for_each_scheme(s, c)
	damon_reclaim_stat = s->stat;

	return damon_reclaim_handle_commit_inputs();
	}

	static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)
	{
	return damon_reclaim_handle_commit_inputs();
	}

	static int __init damon_reclaim_init(void)
	{
	int err = damon_modules_new_paddr_ctx_target(&ctx, &target);

	if (err)
	return err;

	ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;
	ctx->callback.after_aggregation = damon_reclaim_after_aggregation;

	/* 'enabled' has set before this function, probably via command line */
	if (enabled)
	err = damon_reclaim_turn(true);

	return err;
	}

	module_init(damon_reclaim_init);