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/20180518194519.3820-5-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3a554fd..6f153f2 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -83,7 +83,7 @@
/* 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 @@
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
index 48f7587..0170ea8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1695,6 +1695,7 @@
__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);