[RFC PATCH 03/19] mm/damon/core: introduce damon_filter

SeongJae Park
2026-04-26T20:52:35Z

Define a data structure for constructing damon_probe's attributes check,
namely damon_filter. It is very similar to damos_filter but works only
for monitoring purposes. Also embed that into damon_probe, implement
essential handling of the link, with fundamental helpers.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
include/linux/damon.h | 36 ++++++++++++++++++++++++++++++++++++
mm/damon/core.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 66 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 65d7ee0a70ac0..3290792eab547 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -732,12 +732,38 @@ struct damon_intervals_goal {
unsigned long max_sample_us;
};

+/**
+ * enum damon_filter_type - Type of &struct damon_filter
+ *
+ * @DAMON_TEST_TYPE_ANON: Anonymous pages.
+ */
+enum damon_filter_type {
+ DAMON_TEST_TYPE_ANON,
+};
+
+/**
+ * struct damon_filter - DAMON region filter for &struct damon_probe.
+ *
+ * @type: Type of the region.
+ * @matcing: Whether this filter is for the type-matching ones.
+ * @allow: Whether the @type-@matching ones should pass this filter.
+ * @list: Siblings list.
+ */
+struct damon_filter {
+ enum damon_filter_type type;
+ bool matching;
+ bool allow;
+ struct list_head list;
+};
+
/**
* struct damon_probe - Data region attribute probe.
*
+ * @filters: Filters for assessing if a given region is for this probe.
* @list: Siblings list.
*/
struct damon_probe {
+ struct list_head filters;
struct list_head list;
};

@@ -893,6 +919,12 @@ static inline unsigned long damon_sz_region(struct damon_region *r)
return r->ar.end - r->ar.start;
}

+#define damon_for_each_filter(f, p) \
+ list_for_each_entry(f, &p->filters, list)
+
+#define damon_for_each_filter_safe(f, next, p) \
+ list_for_each_entry_safe(f, next, &p->filters, list)
+
#define damon_for_each_probe(p, ctx) \
list_for_each_entry(p, &ctx->probes, list)

@@ -940,6 +972,10 @@ static inline unsigned long damon_sz_region(struct damon_region *r)

#ifdef CONFIG_DAMON

+struct damon_filter *damon_new_filter(enum damon_filter_type type,
+ bool matching, bool allow);
+void damon_add_filter(struct damon_probe *probe, struct damon_filter *f);
+
struct damon_probe *damon_new_probe(void);
void damon_add_probe(struct damon_ctx *ctx, struct damon_probe *probe);

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 861ab977d1edf..170abba8fdf2a 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -109,6 +109,31 @@ int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id)
return err;
}

+struct damon_filter *damon_new_filter(enum damon_filter_type type,
+ bool matching, bool allow)
+{
+ struct damon_filter *filter;
+
+ filter = kmalloc_obj(*filter);
+ if (!filter)
+ return NULL;
+ filter->type = type;
+ filter->matching = matching;
+ filter->allow = allow;
+ INIT_LIST_HEAD(&filter->list);
+ return filter;
+}
+
+void damon_add_filter(struct damon_probe *p, struct damon_filter *f)
+{
+ list_add_tail(&f->list, &p->filters);
+}
+
+static void damon_free_filter(struct damon_filter *f)
+{
+ kfree(f);
+}
+
struct damon_probe *damon_new_probe(void)
{
struct damon_probe *p;
@@ -116,6 +141,7 @@ struct damon_probe *damon_new_probe(void)
p = kmalloc_obj(*p);
if (!p)
return NULL;
+ INIT_LIST_HEAD(&p->filters);
INIT_LIST_HEAD(&p->list);
return p;
}
@@ -132,6 +158,10 @@ static void damon_del_probe(struct damon_probe *p)

static void damon_free_probe(struct damon_probe *p)
{
+ struct damon_filter *f, *next;
+
+ damon_for_each_filter_safe(f, next, p)
+ damon_free_filter(f);
kfree(p);
}

--
2.47.3