[PATCH v3 02/12] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping

From: Matthew Wilcox (Oracle)
Date: Mon Oct 26 2020 - 00:14:36 EST


The comment shows that the reason for using find_get_entries() is now
stale; find_get_pages() will not return 0 if it hits a consecutive run
of swap entries, and I don't believe it has since 2011. pagevec_lookup()
is a simpler function to use than find_get_pages(), so use it instead.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
---
mm/shmem.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 537c137698f8..a33972126b60 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -842,7 +842,6 @@ unsigned long shmem_swap_usage(struct vm_area_struct *vma)
void shmem_unlock_mapping(struct address_space *mapping)
{
struct pagevec pvec;
- pgoff_t indices[PAGEVEC_SIZE];
pgoff_t index = 0;

pagevec_init(&pvec);
@@ -850,16 +849,8 @@ void shmem_unlock_mapping(struct address_space *mapping)
* Minor point, but we might as well stop if someone else SHM_LOCKs it.
*/
while (!mapping_unevictable(mapping)) {
- /*
- * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
- * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
- */
- pvec.nr = find_get_entries(mapping, index,
- PAGEVEC_SIZE, pvec.pages, indices);
- if (!pvec.nr)
+ if (!pagevec_lookup(&pvec, mapping, &index))
break;
- index = indices[pvec.nr - 1] + 1;
- pagevec_remove_exceptionals(&pvec);
check_move_unevictable_pages(&pvec);
pagevec_release(&pvec);
cond_resched();
--
2.28.0