Commit f1d13cac authored by SeongJae Park's avatar SeongJae Park Committed by Andrew Morton
Browse files

mm/damon/sysfs: implement DAMOS tried regions update command 

Implement the code for filling the data of 'tried_regions' DAMON sysfs
directory.  With this commit, DAMON sysfs interface users can write a
special keyword, 'update_schemes_tried_regions' to the corresponding
'state' file of the kdamond.  Then, DAMON sysfs interface will collect the
tried regions information using the 'before_damos_apply()' callback for
one aggregation interval and populate scheme region directories with the
values.

[sj@kernel.org: skip tried regions update if the scheme directory was removed]
  Link: https://lkml.kernel.org/r/20221114182954.4745-2-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-5-sj@kernel.org


Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9277d036

mm/damon/sysfs-common.h

+6 −0
Original line number Diff line number Diff line
@@ -44,3 +44,9 @@ int damon_sysfs_set_schemes(struct damon_ctx *ctx, 
void damon_sysfs_schemes_update_stats(

		struct damon_sysfs_schemes *sysfs_schemes,

		struct damon_ctx *ctx);



int damon_sysfs_schemes_update_regions_start(

		struct damon_sysfs_schemes *sysfs_schemes,

		struct damon_ctx *ctx);



int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx);

mm/damon/sysfs-schemes.c

+80 −0
Original line number Diff line number Diff line
@@ -1244,3 +1244,83 @@ void damon_sysfs_schemes_update_stats( 
		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;

	}

}



/*

 * damon_sysfs_schemes that need to update its schemes regions dir.  Protected

 * by damon_sysfs_lock

 */

static struct damon_sysfs_schemes *damon_sysfs_schemes_for_damos_callback;

static int damon_sysfs_schemes_region_idx;



/*

 * DAMON callback that called before damos apply.  While this callback is

 * registered, damon_sysfs_lock should be held to ensure the regions

 * directories exist.

 */

static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx,

		struct damon_target *t, struct damon_region *r,

		struct damos *s)

{

	struct damos *scheme;

	struct damon_sysfs_scheme_regions *sysfs_regions;

	struct damon_sysfs_scheme_region *region;

	struct damon_sysfs_schemes *sysfs_schemes =

		damon_sysfs_schemes_for_damos_callback;

	int schemes_idx = 0;



	damon_for_each_scheme(scheme, ctx) {

		if (scheme == s)

			break;

		schemes_idx++;

	}



	/* user could have removed the scheme sysfs dir */

	if (schemes_idx >= sysfs_schemes->nr)

		return 0;



	sysfs_regions = sysfs_schemes->schemes_arr[schemes_idx]->tried_regions;

	region = damon_sysfs_scheme_region_alloc(r);

	list_add_tail(&region->list, &sysfs_regions->regions_list);

	sysfs_regions->nr_regions++;

	if (kobject_init_and_add(&region->kobj,

				&damon_sysfs_scheme_region_ktype,

				&sysfs_regions->kobj, "%d",

				damon_sysfs_schemes_region_idx++)) {

		kobject_put(&region->kobj);

	}

	return 0;

}



/* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock */

int damon_sysfs_schemes_update_regions_start(

		struct damon_sysfs_schemes *sysfs_schemes,

		struct damon_ctx *ctx)

{

	struct damos *scheme;

	int schemes_idx = 0;



	damon_for_each_scheme(scheme, ctx) {

		struct damon_sysfs_scheme *sysfs_scheme;



		sysfs_scheme = sysfs_schemes->schemes_arr[schemes_idx++];

		damon_sysfs_scheme_regions_rm_dirs(

				sysfs_scheme->tried_regions);

	}



	damon_sysfs_schemes_for_damos_callback = sysfs_schemes;

	ctx->callback.before_damos_apply = damon_sysfs_before_damos_apply;

	return 0;

}



/*

 * Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock.  Caller

 * should unlock damon_sysfs_lock which held before

 * damon_sysfs_schemes_update_regions_start()

 */

int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx)

{

	damon_sysfs_schemes_for_damos_callback = NULL;

	ctx->callback.before_damos_apply = NULL;

	damon_sysfs_schemes_region_idx = 0;

	return 0;

}

mm/damon/sysfs.c

+55 −2
Original line number Diff line number Diff line
@@ -999,6 +999,11 @@ enum damon_sysfs_cmd { 
	 * files.

	 */

	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,

	/*

	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: Update schemes tried

	 * regions

	 */

	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS,

	/*

	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.

	 */
@@ -1011,6 +1016,7 @@ static const char * const damon_sysfs_cmd_strs[] = { 
	"off",

	"commit",

	"update_schemes_stats",

	"update_schemes_tried_regions",

};



/*
@@ -1193,6 +1199,16 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx, 
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)

{

	struct damon_target *t, *next;

	struct damon_sysfs_kdamond *kdamond;



	/* damon_sysfs_schemes_update_regions_stop() might not yet called */

	kdamond = damon_sysfs_cmd_request.kdamond;

	if (kdamond && damon_sysfs_cmd_request.cmd ==

			DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS &&

			ctx == kdamond->damon_ctx) {

		damon_sysfs_schemes_update_regions_stop(ctx);

		mutex_unlock(&damon_sysfs_lock);

	}



	if (!damon_target_has_pid(ctx))

		return;
@@ -1225,6 +1241,27 @@ static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond) 
	return 0;

}



static int damon_sysfs_upd_schemes_regions_start(

		struct damon_sysfs_kdamond *kdamond)

{

	struct damon_ctx *ctx = kdamond->damon_ctx;



	if (!ctx)

		return -EINVAL;

	return damon_sysfs_schemes_update_regions_start(

			kdamond->contexts->contexts_arr[0]->schemes, ctx);

}



static int damon_sysfs_upd_schemes_regions_stop(

		struct damon_sysfs_kdamond *kdamond)

{

	struct damon_ctx *ctx = kdamond->damon_ctx;



	if (!ctx)

		return -EINVAL;

	return damon_sysfs_schemes_update_regions_stop(ctx);

}



static inline bool damon_sysfs_kdamond_running(

		struct damon_sysfs_kdamond *kdamond)

{
@@ -1277,10 +1314,12 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond) 
static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)

{

	struct damon_sysfs_kdamond *kdamond;

	static bool damon_sysfs_schemes_regions_updating;

	int err = 0;



	/* avoid deadlock due to concurrent state_store('off') */

	if (!mutex_trylock(&damon_sysfs_lock))

	if (!damon_sysfs_schemes_regions_updating &&

			!mutex_trylock(&damon_sysfs_lock))

		return 0;

	kdamond = damon_sysfs_cmd_request.kdamond;

	if (!kdamond || kdamond->damon_ctx != c)
@@ -1292,13 +1331,27 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c) 
	case DAMON_SYSFS_CMD_COMMIT:

		err = damon_sysfs_commit_input(kdamond);

		break;

	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:

		if (!damon_sysfs_schemes_regions_updating) {

			err = damon_sysfs_upd_schemes_regions_start(kdamond);

			if (!err) {

				damon_sysfs_schemes_regions_updating = true;

				goto keep_lock_out;

			}

		} else {

			err = damon_sysfs_upd_schemes_regions_stop(kdamond);

			damon_sysfs_schemes_regions_updating = false;

		}

		break;

	default:

		break;

	}

	/* Mark the request as invalid now. */

	damon_sysfs_cmd_request.kdamond = NULL;

out:

	if (!damon_sysfs_schemes_regions_updating)

		mutex_unlock(&damon_sysfs_lock);

keep_lock_out:

	return err;

}