diff options
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 87 |
1 files changed, 1 insertions, 86 deletions
diff --git a/mm/slub.c b/mm/slub.c index 4b3895cb90e..74c65af0a54 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -149,13 +149,6 @@ static inline void ClearSlabDebug(struct page *page) /* Enable to test recovery from slab corruption on boot */ #undef SLUB_RESILIENCY_TEST -/* - * Currently fastpath is not supported if preemption is enabled. - */ -#if defined(CONFIG_FAST_CMPXCHG_LOCAL) && !defined(CONFIG_PREEMPT) -#define SLUB_FASTPATH -#endif - #if PAGE_SHIFT <= 12 /* @@ -1514,11 +1507,7 @@ static void *__slab_alloc(struct kmem_cache *s, { void **object; struct page *new; -#ifdef SLUB_FASTPATH - unsigned long flags; - local_irq_save(flags); -#endif if (!c->page) goto new_slab; @@ -1541,9 +1530,6 @@ load_freelist: unlock_out: slab_unlock(c->page); stat(c, ALLOC_SLOWPATH); -#ifdef SLUB_FASTPATH - local_irq_restore(flags); -#endif return object; another_slab: @@ -1575,9 +1561,7 @@ new_slab: c->page = new; goto load_freelist; } -#ifdef SLUB_FASTPATH - local_irq_restore(flags); -#endif + /* * No memory available. * @@ -1619,34 +1603,6 @@ static __always_inline void *slab_alloc(struct kmem_cache *s, { void **object; struct kmem_cache_cpu *c; - -/* - * The SLUB_FASTPATH path is provisional and is currently disabled if the - * kernel is compiled with preemption or if the arch does not support - * fast cmpxchg operations. There are a couple of coming changes that will - * simplify matters and allow preemption. Ultimately we may end up making - * SLUB_FASTPATH the default. - * - * 1. The introduction of the per cpu allocator will avoid array lookups - * through get_cpu_slab(). A special register can be used instead. - * - * 2. The introduction of per cpu atomic operations (cpu_ops) means that - * we can realize the logic here entirely with per cpu atomics. The - * per cpu atomic ops will take care of the preemption issues. - */ - -#ifdef SLUB_FASTPATH - c = get_cpu_slab(s, raw_smp_processor_id()); - do { - object = c->freelist; - if (unlikely(is_end(object) || !node_match(c, node))) { - object = __slab_alloc(s, gfpflags, node, addr, c); - break; - } - stat(c, ALLOC_FASTPATH); - } while (cmpxchg_local(&c->freelist, object, object[c->offset]) - != object); -#else unsigned long flags; local_irq_save(flags); @@ -1661,7 +1617,6 @@ static __always_inline void *slab_alloc(struct kmem_cache *s, stat(c, ALLOC_FASTPATH); } local_irq_restore(flags); -#endif if (unlikely((gfpflags & __GFP_ZERO) && object)) memset(object, 0, c->objsize); @@ -1698,11 +1653,6 @@ static void __slab_free(struct kmem_cache *s, struct page *page, void **object = (void *)x; struct kmem_cache_cpu *c; -#ifdef SLUB_FASTPATH - unsigned long flags; - - local_irq_save(flags); -#endif c = get_cpu_slab(s, raw_smp_processor_id()); stat(c, FREE_SLOWPATH); slab_lock(page); @@ -1734,9 +1684,6 @@ checks_ok: out_unlock: slab_unlock(page); -#ifdef SLUB_FASTPATH - local_irq_restore(flags); -#endif return; slab_empty: @@ -1749,9 +1696,6 @@ slab_empty: } slab_unlock(page); stat(c, FREE_SLAB); -#ifdef SLUB_FASTPATH - local_irq_restore(flags); -#endif discard_slab(s, page); return; @@ -1777,34 +1721,6 @@ static __always_inline void slab_free(struct kmem_cache *s, { void **object = (void *)x; struct kmem_cache_cpu *c; - -#ifdef SLUB_FASTPATH - void **freelist; - - c = get_cpu_slab(s, raw_smp_processor_id()); - debug_check_no_locks_freed(object, s->objsize); - do { - freelist = c->freelist; - barrier(); - /* - * If the compiler would reorder the retrieval of c->page to - * come before c->freelist then an interrupt could - * change the cpu slab before we retrieve c->freelist. We - * could be matching on a page no longer active and put the - * object onto the freelist of the wrong slab. - * - * On the other hand: If we already have the freelist pointer - * then any change of cpu_slab will cause the cmpxchg to fail - * since the freelist pointers are unique per slab. - */ - if (unlikely(page != c->page || c->node < 0)) { - __slab_free(s, page, x, addr, c->offset); - break; - } - object[c->offset] = freelist; - stat(c, FREE_FASTPATH); - } while (cmpxchg_local(&c->freelist, freelist, object) != freelist); -#else unsigned long flags; local_irq_save(flags); @@ -1818,7 +1734,6 @@ static __always_inline void slab_free(struct kmem_cache *s, __slab_free(s, page, x, addr, c->offset); local_irq_restore(flags); -#endif } void kmem_cache_free(struct kmem_cache *s, void *x) |