From: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Both shmem_free_swap callers expect the number of pages being freed. In
the large folios context, this needs to support larger values other than
0 (used as 1 page being freed) and -ENOENT (used as 0 pages being
freed). In preparation for large folios adoption, make shmem_free_swap
routine return the number of pages being freed. So, returning 0 in this
context, means 0 pages being freed.
While we are at it, changing to use free_swap_and_cache_nr() to free large
order swap entry by Baolin Wang.
Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 02fb188d627f..d0d54939da48 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -856,18 +856,22 @@ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap)
}
/*
- * Remove swap entry from page cache, free the swap and its page cache.
+ * Remove swap entry from page cache, free the swap and its page cache. Returns
+ * the number of pages being freed. 0 means entry not found in XArray (0 pages
+ * being freed).
*/
-static int shmem_free_swap(struct address_space *mapping,
- pgoff_t index, void *radswap)
+static long shmem_free_swap(struct address_space *mapping,
+ pgoff_t index, void *radswap)
{
+ int order = xa_get_order(&mapping->i_pages, index);
void *old;
old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0);
if (old != radswap)
- return -ENOENT;
- free_swap_and_cache(radix_to_swp_entry(radswap));
- return 0;
+ return 0;
+ free_swap_and_cache_nr(radix_to_swp_entry(radswap), 1 << order);
+
+ return 1 << order;
}
/*
@@ -1019,7 +1023,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (xa_is_value(folio)) {
if (unfalloc)
continue;
- nr_swaps_freed += !shmem_free_swap(mapping,
+ nr_swaps_freed += shmem_free_swap(mapping,
indices[i], folio);
continue;
}
@@ -1086,14 +1090,17 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
folio = fbatch.folios[i];
if (xa_is_value(folio)) {
+ long swaps_freed;
+
if (unfalloc)
continue;
- if (shmem_free_swap(mapping, indices[i], folio)) {
+ swaps_freed = shmem_free_swap(mapping, indices[i], folio);
+ if (!swaps_freed) {
/* Swap was replaced by page: retry */
index = indices[i];
break;
}
- nr_swaps_freed++;
+ nr_swaps_freed += swaps_freed;
continue;
}
--
2.39.3
