[PATCH v4 4/6] mm/damon: introduce DAMOS filter type hugepage

[Usama Arif <usamaarif642@gmail.com>]

This is to gather statistics to check if memory regions of specific
access tempratures are backed by hugepages of a size in a specific
range
This filter can help to observe and prove the effectivenes of
different schemes for shrinking/collapsing hugepages.

Signed-off-by: Usama Arif <usamaarif642@gmail.com>
---
 include/linux/damon.h    | 2 ++
 mm/damon/paddr.c         | 7 +++++++
 mm/damon/sysfs-schemes.c | 1 +
 3 files changed, 10 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 6f30ceeff215..5ba6c2114e3f 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -336,6 +336,7 @@ struct damos_stat {
  * @DAMOS_FILTER_TYPE_ANON:	Anonymous pages.
  * @DAMOS_FILTER_TYPE_MEMCG:	Specific memcg's pages.
  * @DAMOS_FILTER_TYPE_YOUNG:	Recently accessed pages.
+ * @DAMOS_FILTER_TYPE_HUGEPAGE:	Page is part of a hugepage.
  * @DAMOS_FILTER_TYPE_ADDR:	Address range.
  * @DAMOS_FILTER_TYPE_TARGET:	Data Access Monitoring target.
  * @NR_DAMOS_FILTER_TYPES:	Number of filter types.
@@ -355,6 +356,7 @@ enum damos_filter_type {
 	DAMOS_FILTER_TYPE_ANON,
 	DAMOS_FILTER_TYPE_MEMCG,
 	DAMOS_FILTER_TYPE_YOUNG,
+	DAMOS_FILTER_TYPE_HUGEPAGE,
 	DAMOS_FILTER_TYPE_ADDR,
 	DAMOS_FILTER_TYPE_TARGET,
 	NR_DAMOS_FILTER_TYPES,
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 3f59a3fdc391..34fe1eb664cc 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -227,6 +227,7 @@ static bool damos_pa_filter_match(struct damos_filter *filter,
 {
 	bool matched = false;
 	struct mem_cgroup *memcg;
+	size_t folio_sz;
 
 	switch (filter->type) {
 	case DAMOS_FILTER_TYPE_ANON:
@@ -246,6 +247,12 @@ static bool damos_pa_filter_match(struct damos_filter *filter,
 		if (matched)
 			damon_folio_mkold(folio);
 		break;
+#if defined(CONFIG_PGTABLE_HAS_HUGE_LEAVES)
+	case DAMOS_FILTER_TYPE_HUGEPAGE:
+		folio_sz = folio_size(folio);
+		matched = filter->folio_size.min <= folio_sz && folio_sz <= filter->folio_size.max;
+		break;
+#endif
 	default:
 		break;
 	}
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index bc7ca43ca9c4..76aee3ab277e 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -330,6 +330,7 @@ static const char * const damon_sysfs_scheme_filter_type_strs[] = {
 	"anon",
 	"memcg",
 	"young",
+	"hugepage",
 	"addr",
 	"target",
 };
-- 
2.43.5