[PATCH v3 2/6] mm: shmem: add THP validation for PMD-mapped THP related statistics

Baolin Wang
2024-05-30T02:04:40Z

In order to extend support for mTHP, add THP validation for PMD-mapped THP
related statistics to avoid statistical confusion.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
---
mm/shmem.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 6868c0af3a69..ae358efc397a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1647,7 +1647,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
return ERR_PTR(-E2BIG);

folio = shmem_alloc_folio(gfp, HPAGE_PMD_ORDER, info, index);
- if (!folio)
+ if (!folio && pages == HPAGE_PMD_NR)
count_vm_event(THP_FILE_FALLBACK);
} else {
pages = 1;
@@ -1665,7 +1665,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
if (xa_find(&mapping->i_pages, &index,
index + pages - 1, XA_PRESENT)) {
error = -EEXIST;
- } else if (huge) {
+ } else if (pages == HPAGE_PMD_NR) {
count_vm_event(THP_FILE_FALLBACK);
count_vm_event(THP_FILE_FALLBACK_CHARGE);
}
@@ -2031,7 +2031,8 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
folio = shmem_alloc_and_add_folio(huge_gfp,
inode, index, fault_mm, true);
if (!IS_ERR(folio)) {
- count_vm_event(THP_FILE_ALLOC);
+ if (folio_test_pmd_mappable(folio))
+ count_vm_event(THP_FILE_ALLOC);
goto alloced;
}
if (PTR_ERR(folio) == -EEXIST)
--
2.39.3