From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Acked-by: Christoph Lameter <cl@xxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slab.c | 2 -- mm/slub.c | 27 ++------------------------- 2 files changed, 2 insertions(+), 27 deletions(-) diff -puN mm/slab.c~slabslub-remove-rcu_head-size-checks mm/slab.c --- a/mm/slab.c~slabslub-remove-rcu_head-size-checks +++ a/mm/slab.c @@ -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) diff -puN mm/slub.c~slabslub-remove-rcu_head-size-checks mm/slub.c --- a/mm/slub.c~slabslub-remove-rcu_head-size-checks +++ a/mm/slub.c @@ -1686,17 +1686,9 @@ static void __free_slab(struct kmem_cach __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_hea 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_c 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) { _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
