+ mm-damon-sysfs-implement-preps-directory.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/damon/sysfs: implement preps directory
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-sysfs-implement-preps-directory.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-sysfs-implement-preps-directory.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/sysfs: implement preps directory
Date: Tue, 1 Sep 2026 06:24:56 -0700

Implement a sysfs directory named 'preps' under the probe directory.  It
will be evolved to be used for specifying probe preps.

Link: https://lore.kernel.org/20260901132506.99243-10-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/sysfs.c |   65 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 59 insertions(+), 6 deletions(-)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-implement-preps-directory
+++ a/mm/damon/sysfs.c
@@ -750,6 +750,35 @@ static const struct kobj_type damon_sysf
 };
 
 /*
+ * preps directory
+ */
+
+struct damon_sysfs_preps {
+	struct kobject kobj;
+};
+
+static struct damon_sysfs_preps *damon_sysfs_preps_alloc(void)
+{
+	return kzalloc_obj(struct damon_sysfs_preps);
+}
+
+static void damon_sysfs_preps_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_preps, kobj));
+}
+
+static struct attribute *damon_sysfs_preps_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_preps);
+
+static const struct kobj_type damon_sysfs_preps_ktype = {
+	.release = damon_sysfs_preps_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_preps_groups,
+};
+
+/*
  * filter directory
  */
 
@@ -1069,6 +1098,7 @@ static const struct kobj_type damon_sysf
 struct damon_sysfs_probe {
 	struct kobject kobj;
 	unsigned int weight;
+	struct damon_sysfs_preps *preps;
 	struct damon_sysfs_filters *filters;
 };
 
@@ -1079,25 +1109,48 @@ static struct damon_sysfs_probe *damon_s
 
 static int damon_sysfs_probe_add_dirs(struct damon_sysfs_probe *probe)
 {
+	struct damon_sysfs_preps *preps;
 	struct damon_sysfs_filters *filters;
 	int err;
 
-	filters = damon_sysfs_filters_alloc();
-	if (!filters)
+	preps = damon_sysfs_preps_alloc();
+	if (!preps)
 		return -ENOMEM;
+	probe->preps = preps;
+
+	err = kobject_init_and_add(&preps->kobj, &damon_sysfs_preps_ktype,
+			&probe->kobj, "preps");
+	if (err)
+		goto put_preps_out;
+
+	filters = damon_sysfs_filters_alloc();
+	if (!filters) {
+		err = -ENOMEM;
+		goto del_preps_out;
+	}
 	probe->filters = filters;
 
 	err = kobject_init_and_add(&filters->kobj, &damon_sysfs_filters_ktype,
 			&probe->kobj, "filters");
-	if (err) {
-		kobject_put(&filters->kobj);
-		probe->filters = NULL;
-	}
+	if (err)
+		goto put_filters_out;
+	return err;
+
+put_filters_out:
+	kobject_put(&filters->kobj);
+	probe->filters = NULL;
+del_preps_out:
+	kobject_del(&preps->kobj);
+put_preps_out:
+	kobject_put(&preps->kobj);
+	probe->preps = NULL;
 	return err;
 }
 
 static void damon_sysfs_probe_rm_dirs(struct damon_sysfs_probe *probe)
 {
+	if (probe->preps)
+		kobject_put(&probe->preps->kobj);
 	if (probe->filters) {
 		damon_sysfs_filters_rm_dirs(probe->filters);
 		kobject_put(&probe->filters->kobj);
_

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-core-skip-applying-scheme-if-region-split-for-quota-fails.patch
mm-damon-paddr-respect-folio-end-for-damos_stat.patch
mm-damon-paddr-respect-folio-end-for-damos-actions-except-stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_stat.patch
mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch
mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_node_memcg_used_bp.patch
mm-damon-core-handle-extreme-memory-state-in-get_in_active_mem_bp.patch
mm-damon-core-introduce-damon_filter_type_pgidle_unset.patch
mm-damon-paddr-support-pgidle_unset-probe-filter-type.patch
mm-damon-sysfs-support-pgidle_unset-probe-filter-type.patch
docs-mm-damon-design-document-pgidle_unset-probe-filter-type.patch
mm-damon-core-introduce-damon_prep-struct.patch
mm-damon-core-commit-preps.patch
mm-damon-core-introduce-damon_operations-prep_probes.patch
mm-damon-paddr-support-damon_prep.patch
mm-damon-sysfs-implement-preps-directory.patch
mm-damon-sysfs-implement-preps-nr_preps-file.patch
mm-damon-sysfs-create-directories-for-nr_preps-writes.patch
mm-damon-sysfs-implement-prep_action-file.patch
mm-damon-sysfs-pass-preps-to-damon-core.patch
selftests-damon-sysfssh-test-probe-prep-sysfs-files.patch
docs-mm-damon-design-document-probe-preps.patch
docs-admin-guide-mm-damon-usage-document-probe-preps-sysfs-files.patch
docs-abi-damon-document-probe-prep-sysfs-files.patch