The patch titled
Subject: memcg: set page->private before calling swap_readpage
has been added to the -mm tree. Its filename is
memcg-charge-before-adding-to-swapcache-on-swapin-fix.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/memcg-charge-before-adding-to-swapcache-on-swapin-fix.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/memcg-charge-before-adding-to-swapcache-on-swapin-fix.patch
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------------------------------------------------------
From: Shakeel Butt <shakeelb@xxxxxxxxxx>
Subject: memcg: set page->private before calling swap_readpage
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().
Link: https://lkml.kernel.org/r/20210318015959.2986837-1-shakeelb@xxxxxxxxxx
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reported-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/memory.c~memcg-charge-before-adding-to-swapcache-on-swapin-fix
+++ a/mm/memory.c
@@ -3324,7 +3324,11 @@ vm_fault_t do_swap_page(struct vm_fault
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,
_
Patches currently in -mm which might be from shakeelb@xxxxxxxxxx are
memcg-cleanup-root-memcg-checks.patch
memcg-enable-memcg-oom-kill-for-__gfp_nofail.patch
memcg-charge-before-adding-to-swapcache-on-swapin.patch
memcg-charge-before-adding-to-swapcache-on-swapin-fix.patch
