The patch titled Subject: mm: do not reclaim private data from pinned page has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-do-not-reclaim-private-data-from-pinned-page.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Jan Kara jack@suse.cz Subject: mm: do not reclaim private data from pinned page Date: Fri, 28 Apr 2023 14:41:40 +0200

If the page is pinned, there's no point in trying to reclaim it. Furthermore if the page is from the page cache we don't want to reclaim fs-private data from the page because the pinning process may be writing to the page at any time and reclaiming fs private info on a dirty page can upset the filesystem (see link below).

Link: https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz Link: https://lkml.kernel.org/r/20230428124140.30166-1-jack@suse.cz Signed-off-by: Jan Kara jack@suse.cz Reviewed-by: Matthew Wilcox (Oracle) willy@infradead.org Reviewed-by: Lorenzo Stoakes lstoakes@gmail.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: John Hubbard jhubbard@nvidia.com Acked-by: David Hildenbrand david@redhat.com Acked-by: Peter Xu peterx@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/vmscan.c | 10 ++++++++++ 1 file changed, 10 insertions(+)

--- a/mm/vmscan.c~mm-do-not-reclaim-private-data-from-pinned-page +++ a/mm/vmscan.c @@ -1967,6 +1967,16 @@ retry: } }

+ /* + * Folio is unmapped now so it cannot be newly pinned anymore. + * No point in trying to reclaim folio if it is pinned. + * Furthermore we don't want to reclaim underlying fs metadata + * if the folio is pinned and thus potentially modified by the + * pinning process as that may upset the filesystem. + */ + if (folio_maybe_dma_pinned(folio)) + goto activate_locked; + mapping = folio_mapping(folio); if (folio_test_dirty(folio)) { /* _

Patches currently in -mm which might be from jack@suse.cz are

mm-do-not-reclaim-private-data-from-pinned-page.patch