Hi,
While testing my mTHP code I noticed that mm selftests caused an accounting
error in
/sys/kernel/mm/transparent_hugepage/hugepages-2048kB/stats/nr_anon
At first I thought I might have caused a regression, but when retesting with
7.1-rc5 (without my code), the issue was still present.
This issue occurs in two mm selftests:
1) hmm test
2) migration - private_anon_htlb test
I spoke to David about this and he suggested the following diff which seems to
have solved both issues.
David would you like to send a formal patch or patches?
Cheers,
-- Nico
Diff for (1)
diff --git a/mm/memremap.c b/mm/memremap.c
index 053842d45cb1..683a77dd679d 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -425,6 +425,7 @@ void free_zone_device_folio(struct folio *folio)
mem_cgroup_uncharge(folio);
if (folio_test_anon(folio)) {
+ mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON, -1);
for (i = 0; i < nr; i++)
__ClearPageAnonExclusive(folio_page(folio, i));
}
--
2.54.0
For (2) he suggested
diff --git a/mm/migrate.c b/mm/migrate.c
index d9b23909d716..9fd50ea25d2d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -590,7 +590,8 @@ static int __folio_migrate_mapping(struct address_space
*mapping,
/* No turning back from here */
newfolio->index = folio->index;
newfolio->mapping = folio->mapping;
- if (folio_test_anon(folio) && folio_test_large(folio))
+ if (folio_test_anon(folio) && folio_test_large(folio) &&
+ !folio_test_hugetlb(folio))
mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON, 1);
if (folio_test_swapbacked(folio))
__folio_set_swapbacked(newfolio);
@@ -623,7 +624,8 @@ static int __folio_migrate_mapping(struct address_space
*mapping,
*/
newfolio->index = folio->index;
newfolio->mapping = folio->mapping;
- if (folio_test_anon(folio) && folio_test_large(folio))
+ if (folio_test_anon(folio) && folio_test_large(folio) &&
+ !folio_test_hugetlb(folio))
mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON, 1);
folio_ref_add(newfolio, nr); /* add cache reference */
if (folio_test_swapbacked(folio))
--
2.54.0
