From bf68c214df6d73e85fc19b6bbcb642554b491b98 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 7 Jun 2018 17:09:05 -0700 Subject: slab,slub: remove rcu_head size checks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Matthew Wilcox Acked-by: Christoph Lameter Acked-by: Vlastimil Babka Cc: Dave Hansen Cc: Jérôme Glisse Cc: "Kirill A . Shutemov" Cc: Lai Jiangshan Cc: Martin Schwidefsky Cc: Pekka Enberg Cc: Randy Dunlap Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slub.c | 27 ++------------------------- 1 file changed, 2 insertions(+), 25 deletions(-) (limited to 'mm/slub.c') diff --git a/mm/slub.c b/mm/slub.c index a96bf429af08..d5bddf0f4792 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -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) { -- cgit v1.2.3