MM: handle THP in swap_*page_fs() - count_vm_events()

We need to use count_swpout_vm_event() for sio_write_complete() to get
correct counting.

Note that THP swap in (if it ever happens) is current accounted 1 for each
page, whether HUGE or normal.  This is different from swap-out accounting.

This patch should be squashed into
    MM: handle THP in swap_*page_fs()

Link: https://lkml.kernel.org/r/165146948934.24404.5909750610552745025@noble.neil.brown.name
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_io.c b/mm/page_io.c
index d636a35..1b8075e 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -280,8 +280,10 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
                        set_page_dirty(page);
                        ClearPageReclaim(page);
                }
-       } else
-               count_vm_events(PSWPOUT, sio->pages);
+       } else {
+               for (p = 0; p < sio->pages; p++)
+                       count_swpout_vm_event(sio->bvec[p].bv_page);
+       }
 
        for (p = 0; p < sio->pages; p++)
                end_page_writeback(sio->bvec[p].bv_page);