Transparent Huge Pages are currently stored in i_pages as pointers to consecutive subpages. This patch changes that to storing consecutive pointers to the head page in preparation for storing huge pages more efficiently in i_pages. Large parts of this are "inspired" by Kirill's patch https://lore.kernel.org/lkml/20170126115819.58875-2-kirill.shutemov@linux.intel.com/ Kirill and Huang Ying contributed several fixes. [willy@infradead.org: use compound_nr, squish uninit-var warning] Link: http://lkml.kernel.org/r/20190731210400.7419-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Acked-by: Jan Kara <jack@suse.cz> Reviewed-by: Kirill Shutemov <kirill@shutemov.name> Reviewed-by: Song Liu <songliubraving@fb.com> Tested-by: Song Liu <songliubraving@fb.com> Tested-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Tested-by: Qian Cai <cai@lca.pw> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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| @@ -333,6 +333,16 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping, · 332 unmodified lines | |||
| 333 | mapping_gfp_mask(mapping)); | 333 | mapping_gfp_mask(mapping)); |
| 334 | } | 334 | } |
| 335 | 335 | ||
| 336 | static inline struct page *find_subpage(struct page *page, pgoff_t offset) | ||
| 337 | { | ||
| 338 | if (PageHuge(page)) | ||
| 339 | return page; | ||
| 340 | |||
| 341 | VM_BUG_ON_PAGE(PageTail(page), page); | ||
| 342 | |||
| 343 | return page + (offset & (compound_nr(page) - 1)); | ||
| 344 | } | ||
| 345 | |||
| 336 | struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); | 346 | struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); |
| 337 | struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset); | 347 | struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset); |
| 338 | unsigned find_get_entries(struct address_space *mapping, pgoff_t start, | 348 | unsigned find_get_entries(struct address_space *mapping, pgoff_t start, |