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authorSeongJae Park <sj@kernel.org>2026-05-18 16:41:12 -0700
committerAndrew Morton <akpm@linux-foundation.org>2026-05-28 21:31:16 -0700
commite4365733985eeb03dc2847ade3f61875112cdcee (patch)
treef2a2d89e5c6b1e004423febf5432246feaa04c55
parent6f65c423dfa6ea4643e348e2cd4111e8607e27e2 (diff)
downloadlinux-next-history-e4365733985eeb03dc2847ade3f61875112cdcee.tar.gz
mm/damon/sysfs: add filters/<F>/path file
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>
-rw-r--r--mm/damon/sysfs.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index eeb7fdd030cf0..0f6379caf4816 100644
--- a/mm/damon/sysfs.c
+++ b/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 kobject *kobj,
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_filter_matching_attr =
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);