From: Zi Yan <zi.yan@sent.com>
To: gregkh@linuxfoundation.org, stable@vger.kernel.org
Cc: Zi Yan <ziy@nvidia.com>,
linux-mm@kvack.org, Charan Teja Kalla <quic_charante@quicinc.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
Naoya Horiguchi <naoya.horiguchi@linux.dev>
Subject: [PATCH STABLE v6.1.y] mm/migrate: set swap entry values of THP tail pages properly.
Date: Wed, 6 Mar 2024 10:52:17 -0500 [thread overview]
Message-ID: <20240306155217.118467-1-zi.yan@sent.com> (raw)
From: Zi Yan <ziy@nvidia.com>
The tail pages in a THP can have swap entry information stored in their
private field. When migrating to a new page, all tail pages of the new
page need to update ->private to avoid future data corruption.
This fix is stable-only, since after commit 07e09c483cbe ("mm/huge_memory:
work on folio->swap instead of page->private when splitting folio"),
subpages of a swapcached THP no longer requires the maintenance.
Adding THPs to the swapcache was introduced in commit
38d8b4e6bdc87 ("mm, THP, swap: delay splitting THP during swap out"),
where each subpage of a THP added to the swapcache had its own swapcache
entry and required the ->private field to point to the correct swapcache
entry. Later, when THP migration functionality was implemented in commit
616b8371539a6 ("mm: thp: enable thp migration in generic path"),
it initially did not handle the subpages of swapcached THPs, failing to
update their ->private fields or replace the subpage pointers in the
swapcache. Subsequently, commit e71769ae5260 ("mm: enable thp migration
for shmem thp") addressed the swapcache update aspect. This patch fixes
the update of subpage ->private fields.
Closes: https://lore.kernel.org/linux-mm/1707814102-22682-1-git-send-email-quic_charante@quicinc.com/
Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
mm/migrate.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index c93dd6a31c31..c5968021fde0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -423,8 +423,12 @@ int folio_migrate_mapping(struct address_space *mapping,
if (folio_test_swapbacked(folio)) {
__folio_set_swapbacked(newfolio);
if (folio_test_swapcache(folio)) {
+ int i;
+
folio_set_swapcache(newfolio);
- newfolio->private = folio_get_private(folio);
+ for (i = 0; i < nr; i++)
+ set_page_private(folio_page(newfolio, i),
+ page_private(folio_page(folio, i)));
}
entries = nr;
} else {
--
2.43.0
next reply other threads:[~2024-03-06 15:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 15:52 Zi Yan [this message]
2024-03-13 11:23 ` [PATCH STABLE v6.1.y] mm/migrate: set swap entry values of THP tail pages properly Charan Teja Kalla
2024-03-30 9:20 ` Patch "mm/migrate: set swap entry values of THP tail pages properly." has been added to the 6.1-stable tree gregkh
-- strict thread matches above, loose matches on Subject: below --
2024-03-05 16:13 [PATCH STABLE v6.1.y] mm/migrate: set swap entry values of THP tail pages properly Zi Yan
2024-03-05 16:17 ` Zi Yan
2024-03-05 16:22 ` Charan Teja Kalla
2024-03-05 16:26 ` Zi Yan
2024-03-05 16:22 ` David Hildenbrand
2024-03-05 22:04 ` Greg KH
2024-03-05 22:09 ` David Hildenbrand
2024-03-05 22:32 ` Greg KH
2024-03-05 23:13 ` Zi Yan
2024-03-06 13:51 ` Greg KH
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