mm/damon/sysfs: implement a kdamond command for updating schemes' effective quotas

Implement yet another kdamond 'state' file input command, namely
'update_schemes_effective_quotas'.  If it is written, the
'effective_bytes' files of the kdamond will be updated to provide the
current effective size quota of each scheme in bytes.

Link: https://lkml.kernel.org/r/20240219194431.159606-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 678de97fcc88..cc2d88a901f4 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1020,6 +1020,11 @@ enum damon_sysfs_cmd {
 	 */
 	DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS,
 	/*
+	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS: Update the
+	 * effective size quota of the scheme in bytes.
+	 */
+	DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS,
+	/*
 	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
 	 */
 	NR_DAMON_SYSFS_CMDS,
@@ -1035,6 +1040,7 @@ static const char * const damon_sysfs_cmd_strs[] = {
 	"update_schemes_tried_bytes",
 	"update_schemes_tried_regions",
 	"clear_schemes_tried_regions",
+	"update_schemes_effective_quotas",
 };
 
 /*
@@ -1376,6 +1382,29 @@ static int damon_sysfs_commit_schemes_quota_goals(
 }
 
 /*
+ * damon_sysfs_upd_schemes_effective_quotas() - Update schemes effective quotas
+ * sysfs files.
+ * @kdamond:	The kobject wrapper that associated to the kdamond thread.
+ *
+ * This function reads the schemes' effective quotas of specific kdamond and
+ * update the related values for sysfs files.  This function should be called
+ * from DAMON callbacks while holding ``damon_syfs_lock``, to safely access the
+ * DAMON contexts-internal data and DAMON sysfs variables.
+ */
+static int damon_sysfs_upd_schemes_effective_quotas(
+		struct damon_sysfs_kdamond *kdamond)
+{
+	struct damon_ctx *ctx = kdamond->damon_ctx;
+
+	if (!ctx)
+		return -EINVAL;
+	damos_sysfs_update_effective_quotas(
+			kdamond->contexts->contexts_arr[0]->schemes, ctx);
+	return 0;
+}
+
+
+/*
  * damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
  * @c:		The DAMON context of the callback.
  * @active:	Whether @c is not deactivated due to watermarks.
@@ -1437,6 +1466,9 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c, bool active,
 	case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
 		err = damon_sysfs_clear_schemes_regions(kdamond);
 		break;
+	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS:
+		err = damon_sysfs_upd_schemes_effective_quotas(kdamond);
+		break;
 	default:
 		break;
 	}