diff options
author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-01-11 18:04:40 +0300 |
---|---|---|
committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-09-27 16:27:29 +0300 |
commit | 85d0a2ed3747da7f9aedacb72478bbedf06f9f2e (patch) | |
tree | fa38c8b1516f7bca2fbf384a3e4bf96b32dd0977 /include/linux/mm_types.h | |
parent | 889a3747b3b7661b089ba4eae081a3b6bb351a23 (diff) | |
download | linux-85d0a2ed3747da7f9aedacb72478bbedf06f9f2e.tar.xz |
mm: Handle per-folio private data
Add folio_get_private() which mirrors page_private() -- ie folio private
data is the same as page private data. The only difference is that these
return a void * instead of an unsigned long, which matches the majority
of users.
Turn attach_page_private() into folio_attach_private() and reimplement
attach_page_private() as a wrapper. No filesystem which uses page private
data currently supports compound pages, so we're free to define the rules.
attach_page_private() may only be called on a head page; if you want
to add private data to a tail page, you can call set_page_private()
directly (and shouldn't increment the page refcount! That should be
done when adding private data to the head page / folio).
This saves 813 bytes of text with the distro-derived config that I'm
testing due to removing the calls to compound_head() in get_page()
& put_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Diffstat (limited to 'include/linux/mm_types.h')
-rw-r--r-- | include/linux/mm_types.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 6908186629b4..5ebcb86ac934 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -317,6 +317,12 @@ static inline atomic_t *compound_pincount_ptr(struct page *page) #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) +/* + * page_private can be used on tail pages. However, PagePrivate is only + * checked by the VM on the head page. So page_private on the tail pages + * should be used for data that's ancillary to the head page (eg attaching + * buffer heads to tail pages after attaching buffer heads to the head page) + */ #define page_private(page) ((page)->private) static inline void set_page_private(struct page *page, unsigned long private) @@ -324,6 +330,11 @@ static inline void set_page_private(struct page *page, unsigned long private) page->private = private; } +static inline void *folio_get_private(struct folio *folio) +{ + return folio->private; +} + struct page_frag_cache { void * va; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) |