From 213eeb9fd9d66c33109e2ace242df214dc3a653d Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 11 Nov 2011 14:07:14 -0600 Subject: [PATCH] slub: Extract get_freelist from __slab_alloc get_freelist retrieves free objects from the page freelist (put there by remote frees) or deactivates a slab page if no more objects are available. Acked-by: David Rientjes Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- mm/slub.c | 57 ++++++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 25 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 5e410a9..6dc79f8 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2127,6 +2127,37 @@ static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, } /* + * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist + * or deactivate the page. + * + * The page is still frozen if the return value is not NULL. + * + * If this function returns NULL then the page has been unfrozen. + */ +static inline void *get_freelist(struct kmem_cache *s, struct page *page) +{ + struct page new; + unsigned long counters; + void *freelist; + + do { + freelist = page->freelist; + counters = page->counters; + new.counters = counters; + VM_BUG_ON(!new.frozen); + + new.inuse = page->objects; + new.frozen = freelist != NULL; + + } while (!cmpxchg_double_slab(s, page, + freelist, counters, + NULL, new.counters, + "get_freelist")); + + return freelist; +} + +/* * Slow path. The lockless freelist is empty or we need to perform * debugging duties. * @@ -2147,8 +2178,6 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, { void **object; unsigned long flags; - struct page new; - unsigned long counters; local_irq_save(flags); #ifdef CONFIG_PREEMPT @@ -2176,29 +2205,7 @@ redo: stat(s, ALLOC_SLOWPATH); - do { - object = c->page->freelist; - counters = c->page->counters; - new.counters = counters; - VM_BUG_ON(!new.frozen); - - /* - * If there is no object left then we use this loop to - * deactivate the slab which is simple since no objects - * are left in the slab and therefore we do not need to - * put the page back onto the partial list. - * - * If there are objects left then we retrieve them - * and use them to refill the per cpu queue. - */ - - new.inuse = c->page->objects; - new.frozen = object != NULL; - - } while (!__cmpxchg_double_slab(s, c->page, - object, counters, - NULL, new.counters, - "__slab_alloc")); + object = get_freelist(s, c->page); if (!object) { c->page = NULL; -- 2.7.4