diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-08-16 16:12:00 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-21 14:28:45 -0700 |
| commit | b10ff04dc0ec7cc7dbb0eac98c4202ec8d28c21b (patch) | |
| tree | 16e15a8401c4620bedbd2468da6e9ddd13c580be /include/linux/mm_types.h | |
| parent | 6199277baf73a4877b42991b97c40e173e530756 (diff) | |
mm: add tail private fields to struct folio
Because THP_SWAP uses page->private for each page, we must not use the
space which overlaps that field for anything which would conflict with
that. We avoid the conflict on 32-bit systems by disallowing THP_SWAP on
32-bit.
Link: https://lkml.kernel.org/r/20230816151201.3655946-13-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/mm_types.h')
| -rw-r--r-- | include/linux/mm_types.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 40afb3bbc309..06e9315bfe7c 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -322,8 +322,11 @@ struct folio { atomic_t _pincount; #ifdef CONFIG_64BIT unsigned int _folio_nr_pages; -#endif + /* 4 byte gap here */ /* private: the union with struct page is transitional */ + /* Fix THP_SWAP to not use tail->private */ + unsigned long _private_1; +#endif }; struct page __page_1; }; @@ -344,6 +347,9 @@ struct folio { /* public: */ struct list_head _deferred_list; /* private: the union with struct page is transitional */ + unsigned long _avail_2a; + /* Fix THP_SWAP to not use tail->private */ + unsigned long _private_2a; }; struct page __page_2; }; @@ -368,12 +374,18 @@ FOLIO_MATCH(memcg_data, memcg_data); offsetof(struct page, pg) + sizeof(struct page)) FOLIO_MATCH(flags, _flags_1); FOLIO_MATCH(compound_head, _head_1); +#ifdef CONFIG_64BIT +FOLIO_MATCH(private, _private_1); +#endif #undef FOLIO_MATCH #define FOLIO_MATCH(pg, fl) \ static_assert(offsetof(struct folio, fl) == \ offsetof(struct page, pg) + 2 * sizeof(struct page)) FOLIO_MATCH(flags, _flags_2); FOLIO_MATCH(compound_head, _head_2); +FOLIO_MATCH(flags, _flags_2a); +FOLIO_MATCH(compound_head, _head_2a); +FOLIO_MATCH(private, _private_2a); #undef FOLIO_MATCH /** |