swap: turn get_swap_page() into folio_alloc_swap()
This removes an assumption that a large folio is HPAGE_PMD_NR pages
in size.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9398e91..bfa41bf 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -77,9 +77,9 @@ static PLIST_HEAD(swap_active_head);
/*
* all available (active, not full) swap_info_structs
* protected with swap_avail_lock, ordered by priority.
- * This is used by get_swap_page() instead of swap_active_head
+ * This is used by folio_alloc_swap() instead of swap_active_head
* because swap_active_head includes all swap_info_structs,
- * but get_swap_page() doesn't need to look at full ones.
+ * but folio_alloc_swap() doesn't need to look at full ones.
* This uses its own lock instead of swap_lock because when a
* swap_info_struct changes between not-full/full, it needs to
* add/remove itself to/from this list, but the swap_info_struct->lock
@@ -2109,11 +2109,12 @@ static int try_to_unuse(unsigned int type)
* Under global memory pressure, swap entries can be reinserted back
* into process space after the mmlist loop above passes over them.
*
- * Limit the number of retries? No: when mmget_not_zero() above fails,
- * that mm is likely to be freeing swap from exit_mmap(), which proceeds
- * at its own independent pace; and even shmem_writepage() could have
- * been preempted after get_swap_page(), temporarily hiding that swap.
- * It's easy and robust (though cpu-intensive) just to keep retrying.
+ * Limit the number of retries? No: when mmget_not_zero()
+ * above fails, that mm is likely to be freeing swap from
+ * exit_mmap(), which proceeds at its own independent pace;
+ * and even shmem_writepage() could have been preempted after
+ * folio_alloc_swap(), temporarily hiding that swap. It's easy
+ * and robust (though cpu-intensive) just to keep retrying.
*/
if (READ_ONCE(si->inuse_pages)) {
if (!signal_pending(current))
@@ -2327,7 +2328,7 @@ static void _enable_swap_info(struct swap_info_struct *p)
* which on removal of any swap_info_struct with an auto-assigned
* (i.e. negative) priority increments the auto-assigned priority
* of any lower-priority swap_info_structs.
- * swap_avail_head needs to be priority ordered for get_swap_page(),
+ * swap_avail_head needs to be priority ordered for folio_alloc_swap(),
* which allocates swap pages from the highest available priority
* swap_info_struct.
*/
