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* [PATCH] memcg: set page->private before calling swap_readpage
@ 2021-03-18  1:59 Shakeel Butt
       [not found] ` <20210318015959.2986837-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
  0 siblings, 1 reply; 6+ messages in thread
From: Shakeel Butt @ 2021-03-18  1:59 UTC (permalink / raw)
  To: Hugh Dickins, Johannes Weiner
  Cc: Roman Gushchin, Michal Hocko, Andrew Morton, Minchan Kim,
	cgroups-u79uwXL29TY76Z2rM5mHXA, linux-mm-Bw31MaZKKs3YtjvyW6yDsg,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA, Shakeel Butt, Heiko Carstens

The function swap_readpage() (and other functions it call) extracts swap
entry from page->private. However for SWP_SYNCHRONOUS_IO, the kernel
skips the swapcache and thus we need to manually set the page->private
with the swap entry before calling swap_readpage().

Signed-off-by: Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Reported-by: Heiko Carstens <hca-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---

Andrew, please squash this into "memcg: charge before adding to
swapcache on swapin" patch.

 mm/memory.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/memory.c b/mm/memory.c
index aefd158ae1ea..b6f3410b5902 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3324,7 +3324,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 					workingset_refault(page, shadow);
 
 				lru_cache_add(page);
+
+				/* To provide entry to swap_readpage() */
+				set_page_private(page, entry.val);
 				swap_readpage(page, true);
+				set_page_private(page, 0);
 			}
 		} else {
 			page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
-- 
2.31.0.rc2.261.g7f71774620-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-03-18 15:08 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2021-03-18  1:59 [PATCH] memcg: set page->private before calling swap_readpage Shakeel Butt
     [not found] ` <20210318015959.2986837-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2021-03-18  8:55   ` Heiko Carstens
2021-03-18 14:01   ` Michal Hocko
     [not found]     ` <YFNdNeczjnmF55bm-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2021-03-18 15:02       ` Johannes Weiner
2021-03-18 15:08         ` Michal Hocko
2021-03-18 15:03   ` Johannes Weiner

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