mm: switch s_mem and slab_cache in struct page

This will allow us to store slub's counters in the same bits as slab's s_mem. slub now needs to set page->mapping to NULL as it frees the page, just like slab does. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox <[email protected]> Acked-by: Christoph Lameter <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Jérôme Glisse <[email protected]> Cc: "Kirill A . Shutemov" <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Pekka Enberg <[email protected]> Cc: Randy Dunlap <[email protected]> Cc: Andrey Ryabinin <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
dbaluta · Jun 8, 2018 · d4fc506 · d4fc506
1 parent 1d40a5e
commit d4fc506
Show file tree

Hide file tree

Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
@@ -83,7 +83,7 @@ struct page {
 		/* See page-flags.h for the definition of PAGE_MAPPING_FLAGS */
 		struct address_space *mapping;
 
-		void *s_mem;			/* slab first object */
+		struct kmem_cache *slab_cache;	/* SL[AU]B: Pointer to slab */
 		atomic_t compound_mapcount;	/* first tail page */
 		/* page_deferred_list().next	 -- second tail page */
 	};
@@ -194,7 +194,7 @@ struct page {
 		spinlock_t ptl;
 #endif
 #endif
-		struct kmem_cache *slab_cache;	/* SL[AU]B: Pointer to slab */
+		void *s_mem;			/* slab first object */
 	};
 
 #ifdef CONFIG_MEMCG

diff --git a/mm/slub.c b/mm/slub.c
@@ -1695,6 +1695,7 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 	__ClearPageSlab(page);
 
 	page_mapcount_reset(page);
+	page->mapping = NULL;
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += pages;
 	memcg_uncharge_slab(page, order, s);