diff mbox series

[v4,02/16] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping

Message ID 20201112212641.27837-3-willy@infradead.org (mailing list archive)
State New, archived
Headers show
Series Overhaul multi-page lookups for THP | expand

Commit Message

Matthew Wilcox Nov. 12, 2020, 9:26 p.m. UTC 
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@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
 mm/shmem.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

Comments

Christoph Hellwig Nov. 14, 2020, 9:53 a.m. UTC | #1 
On Thu, Nov 12, 2020 at 09:26:27PM +0000, Matthew Wilcox (Oracle) wrote:
> 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@infradead.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: William Kucharski <william.kucharski@oracle.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/mm/shmem.c b/mm/shmem.c
index 028f4596fc16..8076c171731c 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();