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-rw-r--r--mm/page_io.c54
1 files changed, 0 insertions, 54 deletions
diff --git a/mm/page_io.c b/mm/page_io.c
index bcf27d057253..f0e3f2be7b44 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -69,54 +69,6 @@ void end_swap_bio_write(struct bio *bio)
bio_put(bio);
}
-static void swap_slot_free_notify(struct page *page)
-{
- struct swap_info_struct *sis;
- struct gendisk *disk;
- swp_entry_t entry;
-
- /*
- * There is no guarantee that the page is in swap cache - the software
- * suspend code (at least) uses end_swap_bio_read() against a non-
- * swapcache page. So we must check PG_swapcache before proceeding with
- * this optimization.
- */
- if (unlikely(!PageSwapCache(page)))
- return;
-
- sis = page_swap_info(page);
- if (!(sis->flags & SWP_BLKDEV))
- return;
-
- /*
- * The swap subsystem performs lazy swap slot freeing,
- * expecting that the page will be swapped out again.
- * So we can avoid an unnecessary write if the page
- * isn't redirtied.
- * This is good for real swap storage because we can
- * reduce unnecessary I/O and enhance wear-leveling
- * if an SSD is used as the as swap device.
- * But if in-memory swap device (eg zram) is used,
- * this causes a duplicated copy between uncompressed
- * data in VM-owned memory and compressed data in
- * zram-owned memory. So let's free zram-owned memory
- * and make the VM-owned decompressed page *dirty*,
- * so the page should be swapped out somewhere again if
- * we again wish to reclaim it.
- */
- disk = sis->bdev->bd_disk;
- entry.val = page_private(page);
- if (disk->fops->swap_slot_free_notify && __swap_count(entry) == 1) {
- unsigned long offset;
-
- offset = swp_offset(entry);
-
- SetPageDirty(page);
- disk->fops->swap_slot_free_notify(sis->bdev,
- offset);
- }
-}
-
static void end_swap_bio_read(struct bio *bio)
{
struct page *page = bio_first_page_all(bio);
@@ -132,7 +84,6 @@ static void end_swap_bio_read(struct bio *bio)
}
SetPageUptodate(page);
- swap_slot_free_notify(page);
out:
unlock_page(page);
WRITE_ONCE(bio->bi_private, NULL);
@@ -371,11 +322,6 @@ int swap_readpage(struct page *page, bool synchronous)
ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
if (!ret) {
- if (trylock_page(page)) {
- swap_slot_free_notify(page);
- unlock_page(page);
- }
-
count_vm_event(PSWPIN);
return 0;
}