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authorMatthew Wilcox <willy@infradead.org>2019-05-14 03:16:44 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:47:45 +0300
commit5fd4ca2d84b249f0858ce28cf637cf25b61a398f (patch)
treea7660b8f5f9fa02945070e2ab918eb645c92ba36 /include/linux/pagemap.h
parentcefdca0a86be517bc390fc4541e3674b8e7803b0 (diff)
downloadlinux-5fd4ca2d84b249f0858ce28cf637cf25b61a398f.tar.xz
mm: page cache: store only head pages in i_pages
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/ [willy@infradead.org: fix swapcache pages] Link: http://lkml.kernel.org/r/20190324155441.GF10344@bombadil.infradead.org [kirill@shutemov.name: hugetlb stores pages in page cache differently] Link: http://lkml.kernel.org/r/20190404134553.vuvhgmghlkiw2hgl@kshutemo-mobl1 Link: http://lkml.kernel.org/r/20190307153051.18815-1-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-and-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> Cc: Hugh Dickins <hughd@google.com> Cc: Song Liu <liu.song.a23@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pagemap.h')
-rw-r--r--include/linux/pagemap.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index bcf909d0de5f..2e8438a1216a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -333,6 +333,19 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
mapping_gfp_mask(mapping));
}
+static inline struct page *find_subpage(struct page *page, pgoff_t offset)
+{
+ unsigned long mask;
+
+ if (PageHuge(page))
+ return page;
+
+ VM_BUG_ON_PAGE(PageTail(page), page);
+
+ mask = (1UL << compound_order(page)) - 1;
+ return page + (offset & mask);
+}
+
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,