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Commit bf68c214 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

slab,slub: remove rcu_head size checks 

rcu_head may now grow larger than list_head without affecting slab or
slub.

Link: http://lkml.kernel.org/r/20180518194519.3820-15-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarVlastimil 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 50e7fbc3

mm/slab.c

+0 −2
Original line number Diff line number Diff line
@@ -1235,8 +1235,6 @@ void __init kmem_cache_init(void) 
{

	int i;



	BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <

					sizeof(struct rcu_head));

	kmem_cache = &kmem_cache_boot;



	if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1)

mm/slub.c

+2 −25
Original line number Diff line number Diff line
@@ -1686,17 +1686,9 @@ static void __free_slab(struct kmem_cache *s, struct page *page) 
	__free_pages(page, order);

}



#define need_reserve_slab_rcu						\

	(sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))



static void rcu_free_slab(struct rcu_head *h)

{

	struct page *page;



	if (need_reserve_slab_rcu)

		page = virt_to_head_page(h);

	else

		page = container_of((struct list_head *)h, struct page, lru);

	struct page *page = container_of(h, struct page, rcu_head);



	__free_slab(page->slab_cache, page);

}
@@ -1704,19 +1696,7 @@ static void rcu_free_slab(struct rcu_head *h) 
static void free_slab(struct kmem_cache *s, struct page *page)

{

	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {

		struct rcu_head *head;



		if (need_reserve_slab_rcu) {

			int order = compound_order(page);

			int offset = (PAGE_SIZE << order) - s->reserved;



			VM_BUG_ON(s->reserved != sizeof(*head));

			head = page_address(page) + offset;

		} else {

			head = &page->rcu_head;

		}



		call_rcu(head, rcu_free_slab);

		call_rcu(&page->rcu_head, rcu_free_slab);

	} else

		__free_slab(s, page);

}
@@ -3583,9 +3563,6 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags) 
	s->random = get_random_long();

#endif



	if (need_reserve_slab_rcu && (s->flags & SLAB_TYPESAFE_BY_RCU))

		s->reserved = sizeof(struct rcu_head);



	if (!calculate_sizes(s, -1))

		goto error;

	if (disable_higher_order_debug) {