+ mm-damon-sysfs-add-filters-f-path-file.patch added to mm-new branch

+ mm-damon-sysfs-add-filters-f-path-file.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/damon/sysfs: add filters/<F>/path file
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-sysfs-add-filters-f-path-file.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-add-filters-f-path-file.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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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/sysfs: add filters/<F>/path file
Date: Mon, 18 May 2026 16:41:12 -0700

Introduce a new DAMON sysfs file for letting users setup the target memory
cgroup of the belonging memory cgroup attribute monitoring.  The file is
named 'path', located under the probe filter directory.  Users can set the
target memory cgroup by writing the path to the memory cgroup from the
cgroup mount point to the file.

Link: https://lore.kernel.org/20260518234119.97569-25-sj@kernel.org
Signed-off-by: SeongJae 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: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.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 |   44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-add-filters-f-path-file
+++ a/mm/damon/sysfs.c
@@ -756,6 +756,7 @@ struct damon_sysfs_filter {
 	enum damon_filter_type type;
 	bool matching;
 	bool allow;
+	char *path;
 };
 
 static struct damon_sysfs_filter *damon_sysfs_filter_alloc(void)
@@ -774,6 +775,10 @@ damon_sysfs_filter_type_names[] = {
 		.type = DAMON_FILTER_TYPE_ANON,
 		.name = "anon",
 	},
+	{
+		.type = DAMON_FILTER_TYPE_MEMCG,
+		.name = "memcg",
+	},
 };
 
 static ssize_t type_show(struct kobject *kobj,
@@ -862,11 +867,46 @@ static ssize_t allow_store(struct kobjec
 	return count;
 }
 
+static ssize_t path_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	int len;
+
+	if (!mutex_trylock(&damon_sysfs_lock))
+		return -EBUSY;
+	len = sysfs_emit(buf, "%s\n", filter->path ? filter->path : "");
+	mutex_unlock(&damon_sysfs_lock);
+	return len;
+}
+
+static ssize_t path_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	char *path = kmalloc_objs(*path, size_add(count, 1));
+
+	if (!path)
+		return -ENOMEM;
+	strscpy(path, buf, size_add(count, 1));
+	if (!mutex_trylock(&damon_sysfs_lock)) {
+		kfree(path);
+		return -EBUSY;
+	}
+	kfree(filter->path);
+	filter->path = path;
+	mutex_unlock(&damon_sysfs_lock);
+	return count;
+}
+
 static void damon_sysfs_filter_release(struct kobject *kobj)
 {
 	struct damon_sysfs_filter *filter = container_of(kobj,
 			struct damon_sysfs_filter, kobj);
 
+	kfree(filter->path);
 	kfree(filter);
 }
 
@@ -879,10 +919,14 @@ static struct kobj_attribute damon_sysfs
 static struct kobj_attribute damon_sysfs_filter_allow_attr =
 		__ATTR_RW_MODE(allow, 0600);
 
+static struct kobj_attribute damon_sysfs_filter_path_attr =
+		__ATTR_RW_MODE(path, 0600);
+
 static struct attribute *damon_sysfs_filter_attrs[] = {
 	&damon_sysfs_filter_type_attr.attr,
 	&damon_sysfs_filter_matching_attr.attr,
 	&damon_sysfs_filter_allow_attr.attr,
+	&damon_sysfs_filter_path_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_filter);
_

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

mm-damon-sysfs-schemes-delete-tried-region-in-regions_rmdirs.patch
mm-damon-core-make-charge_addr_from-aware-of-end-address-exclusivity.patch
mm-damon-core-handle-min_region_sz-remaining-quota-as-empty.patch
mm-damon-core-merge-regions-after-applying-damos-schemes.patch
mm-damon-core-introduce-failed-region-quota-charge-ratio.patch
mm-damon-sysfs-schemes-implement-fail_charge_numdenom-files.patch
docs-mm-damon-design-document-fail_charge_numdenom.patch
docs-admin-guide-mm-damon-usage-document-fail_charge_numdenom-files.patch
docs-abi-damon-document-fail_charge_numdenom.patch
mm-damon-tests-core-kunit-test-fail_charge_numdenom-committing.patch
selftests-damon-_damon_sysfs-support-failed-region-quota-charge-ratio.patch
selftests-damon-drgn_dump_damon_status-support-failed-region-quota-charge-ratio.patch
selftests-damon-sysfspy-test-failed-region-quota-charge-ratio.patch
docs-mm-damon-maintainer-profile-add-ai-review-usage-guideline.patch
mm-damon-core-introduce-damon_ctx-paused.patch
mm-damon-sysfs-add-pause-file-under-context-dir.patch
docs-mm-damon-design-update-for-context-pause-resume-feature.patch
docs-admin-guide-mm-damon-usage-update-for-pause-file.patch
docs-abi-damon-update-for-pause-sysfs-file.patch
mm-damon-tests-core-kunit-test-pause-commitment.patch
selftests-damon-_damon_sysfs-support-pause-file-staging.patch
selftests-damon-drgn_dump_damon_status-dump-pause.patch
selftests-damon-sysfspy-check-pause-on-assert_ctx_committed.patch
selftests-damon-sysfspy-pause-damon-before-dumping-status.patch
mm-damon-introduce-damon_set_region_system_rams_default.patch
mm-damon-reclaim-cover-all-system-rams.patch
mm-damon-lru_sort-cover-all-system-rams.patch
mm-damon-core-remove-damon_set_region_biggest_system_ram_default.patch
mm-damon-stat-use-damon_set_region_system_rams_default.patch
docs-admin-guide-mm-damon-reclaim-update-for-entire-memory-monitoring.patch
docs-admin-guide-mm-damon-lru_sort-update-for-entire-memory-monitoring.patch
docs-admin-guide-mm-damon-usage-mark-scheme-filters-sysfs-dir-as-deprecated.patch
docs-abi-damon-mark-schemes-s-filters-deprecated.patch
mm-damon-reclaim-add-autotune_monitoring_intervals-parameter.patch
docs-admin-guide-mm-damon-reclaim-update-for-autotune_monitoring_intervals.patch
mm-damon-stat-add-a-parameter-for-reading-kdamond-pid.patch
docs-admin-guide-mm-damon-stat-document-kdamond_pid-parameter.patch
mm-damon-core-introduce-struct-damon_probe.patch
mm-damon-core-embed-damon_probe-objects-in-damon_ctx.patch
mm-damon-core-introduce-damon_filter.patch
mm-damon-core-commit-probes.patch
mm-damon-core-introduce-damon_region-probe_hits.patch
mm-damon-core-introduce-damon_ops-apply_probes.patch
mm-damon-core-do-data-attributes-monitoring.patch
mm-damon-paddr-support-data-attributes-monitoring.patch
mm-damon-sysfs-implement-probes-dir.patch
mm-damon-sysfs-implement-probe-dir.patch
mm-damon-sysfs-implement-filters-directory.patch
mm-damon-sysfs-implement-filter-dir.patch
mm-damon-sysfs-implement-filter-dir-files.patch
mm-damon-sysfs-setup-probes-on-damon-core-api-parameters.patch
mm-damon-sysfs-schemes-implement-tried_regions-r-probes.patch
mm-damon-sysfs-schemes-implement-probe-dir.patch
mm-damon-sysfs-schemes-implement-probe-hits-file.patch
mm-damon-trace-probe_hits.patch
selftests-damon-sysfssh-test-probes-dir.patch
docs-mm-damon-design-document-data-attributes-monitoring.patch
docs-admin-guide-mm-damon-usage-document-data-attributes-monitoring.patch
mm-damon-core-introduce-damon_filter_type_memcg.patch
mm-damon-paddr-support-damon_filter_type_memcg.patch
mm-damon-sysfs-add-filters-f-path-file.patch
mm-damon-sysfs-schemes-move-memcg_path_to_id-to-sysfs-common.patch
mm-damon-sysfs-setup-damon_filter-memcg_id-from-path.patch
docs-mm-damon-design-update-for-memcg-damon-filter.patch
docs-admin-guide-mm-damon-usage-update-for-memcg-damon-filter.patch