1 files changed, 62 insertions, 113 deletions

diff --git a/mm/slub.c b/mm/slub.c
index e2989ae243b5..74c65af0a54f 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
 
 /*
@@ -211,6 +204,8 @@ static inline void ClearSlabDebug(struct page *page)
 /* Internal SLUB flags */
 #define __OBJECT_POISON         0x80000000 /* Poison object */
 #define __SYSFS_ADD_DEFERRED    0x40000000 /* Not yet visible via sysfs */
+#define __KMALLOC_CACHE         0x20000000 /* objects freed using kfree */
+#define __PAGE_ALLOC_FALLBACK   0x10000000 /* Allow fallback to page alloc */
 
 /* Not all arches define cache_line_size */
 #ifndef cache_line_size
@@ -308,7 +303,7 @@ static inline int is_end(void *addr)
         return (unsigned long)addr & PAGE_MAPPING_ANON;
 }
 
-void *slab_address(struct page *page)
+static void *slab_address(struct page *page)
 {
         return page->end - PAGE_MAPPING_ANON;
 }
@@ -1078,14 +1073,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         struct page *page;
         int pages = 1 << s->order;
 
-        if (s->order)
-                flags |= __GFP_COMP;
-
-        if (s->flags & SLAB_CACHE_DMA)
-                flags |= SLUB_DMA;
-
-        if (s->flags & SLAB_RECLAIM_ACCOUNT)
-                flags |= __GFP_RECLAIMABLE;
+        flags |= s->allocflags;
 
         if (node == -1)
                 page = alloc_pages(flags, s->order);
@@ -1519,11 +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;
 
@@ -1546,10 +1530,6 @@ load_freelist:
 unlock_out:
         slab_unlock(c->page);
         stat(c, ALLOC_SLOWPATH);
-out:
-#ifdef SLUB_FASTPATH
-        local_irq_restore(flags);
-#endif
         return object;
 
 another_slab:
@@ -1581,8 +1561,22 @@ new_slab:
                 c->page = new;
                 goto load_freelist;
         }
-        object = NULL;
-        goto out;
+
+        /*
+         * No memory available.
+         *
+         * If the slab uses higher order allocs but the object is
+         * smaller than a page size then we can fallback in emergencies
+         * to the page allocator via kmalloc_large. The page allocator may
+         * have failed to obtain a higher order page and we can try to
+         * allocate a single page if the object fits into a single page.
+         * That is only possible if certain conditions are met that are being
+         * checked when a slab is created.
+         */
+        if (!(gfpflags & __GFP_NORETRY) && (s->flags & __PAGE_ALLOC_FALLBACK))
+                return kmalloc_large(s->objsize, gfpflags);
+
+        return NULL;
 debug:
         object = c->page->freelist;
         if (!alloc_debug_processing(s, c->page, object, addr))
@@ -1609,34 +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);
@@ -1651,7 +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);
@@ -1688,11 +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);
@@ -1724,9 +1684,6 @@ checks_ok:
 
 out_unlock:
         slab_unlock(page);
-#ifdef SLUB_FASTPATH
-        local_irq_restore(flags);
-#endif
         return;
 
 slab_empty:
@@ -1739,9 +1696,6 @@ slab_empty:
         }
         slab_unlock(page);
         stat(c, FREE_SLAB);
-#ifdef SLUB_FASTPATH
-        local_irq_restore(flags);
-#endif
         discard_slab(s, page);
         return;
 
@@ -1767,34 +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);
@@ -1808,7 +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)
@@ -2329,10 +2254,33 @@ static int calculate_sizes(struct kmem_cache *s)
         size = ALIGN(size, align);
         s->size = size;
 
-        s->order = calculate_order(size);
+        if ((flags & __KMALLOC_CACHE) &&
+                        PAGE_SIZE / size < slub_min_objects) {
+                /*
+                 * Kmalloc cache that would not have enough objects in
+                 * an order 0 page. Kmalloc slabs can fallback to
+                 * page allocator order 0 allocs so take a reasonably large
+                 * order that will allows us a good number of objects.
+                 */
+                s->order = max(slub_max_order, PAGE_ALLOC_COSTLY_ORDER);
+                s->flags |= __PAGE_ALLOC_FALLBACK;
+                s->allocflags |= __GFP_NOWARN;
+        } else
+                s->order = calculate_order(size);
+
         if (s->order < 0)
                 return 0;
 
+        s->allocflags = 0;
+        if (s->order)
+                s->allocflags |= __GFP_COMP;
+
+        if (s->flags & SLAB_CACHE_DMA)
+                s->allocflags |= SLUB_DMA;
+
+        if (s->flags & SLAB_RECLAIM_ACCOUNT)
+                s->allocflags |= __GFP_RECLAIMABLE;
+
         /*
          * Determine the number of objects per slab
          */
@@ -2484,11 +2432,11 @@ EXPORT_SYMBOL(kmem_cache_destroy);
  *              Kmalloc subsystem
  *******************************************************************/
 
-struct kmem_cache kmalloc_caches[PAGE_SHIFT] __cacheline_aligned;
+struct kmem_cache kmalloc_caches[PAGE_SHIFT + 1] __cacheline_aligned;
 EXPORT_SYMBOL(kmalloc_caches);
 
 #ifdef CONFIG_ZONE_DMA
-static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT];
+static struct kmem_cache *kmalloc_caches_dma[PAGE_SHIFT + 1];
 #endif
 
 static int __init setup_slub_min_order(char *str)
@@ -2536,7 +2484,7 @@ static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
 
         down_write(&slub_lock);
         if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
-                        flags, NULL))
+                        flags | __KMALLOC_CACHE, NULL))
                 goto panic;
 
         list_add(&s->list, &slab_caches);
@@ -2670,9 +2618,8 @@ void *__kmalloc(size_t size, gfp_t flags)
 {
         struct kmem_cache *s;
 
-        if (unlikely(size > PAGE_SIZE / 2))
-                return (void *)__get_free_pages(flags | __GFP_COMP,
-                                                        get_order(size));
+        if (unlikely(size > PAGE_SIZE))
+                return kmalloc_large(size, flags);
 
         s = get_slab(size, flags);
 
@@ -2688,9 +2635,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 {
         struct kmem_cache *s;
 
-        if (unlikely(size > PAGE_SIZE / 2))
-                return (void *)__get_free_pages(flags | __GFP_COMP,
-                                                        get_order(size));
+        if (unlikely(size > PAGE_SIZE))
+                return kmalloc_large(size, flags);
 
         s = get_slab(size, flags);
 
@@ -3001,7 +2947,7 @@ void __init kmem_cache_init(void)
                 caches++;
         }
 
-        for (i = KMALLOC_SHIFT_LOW; i < PAGE_SHIFT; i++) {
+        for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++) {
                 create_kmalloc_cache(&kmalloc_caches[i],
                         "kmalloc", 1 << i, GFP_KERNEL);
                 caches++;
@@ -3028,7 +2974,7 @@ void __init kmem_cache_init(void)
         slab_state = UP;
 
         /* Provide the correct kmalloc names now that the caches are up */
-        for (i = KMALLOC_SHIFT_LOW; i < PAGE_SHIFT; i++)
+        for (i = KMALLOC_SHIFT_LOW; i <= PAGE_SHIFT; i++)
                 kmalloc_caches[i]. name =
                         kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
 
@@ -3057,6 +3003,9 @@ static int slab_unmergeable(struct kmem_cache *s)
         if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
                 return 1;
 
+        if ((s->flags & __PAGE_ALLOC_FALLBACK))
+                return 1;
+
         if (s->ctor)
                 return 1;
 
@@ -3218,9 +3167,9 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
 {
         struct kmem_cache *s;
 
-        if (unlikely(size > PAGE_SIZE / 2))
-                return (void *)__get_free_pages(gfpflags | __GFP_COMP,
-                                                        get_order(size));
+        if (unlikely(size > PAGE_SIZE))
+                return kmalloc_large(size, gfpflags);
+
         s = get_slab(size, gfpflags);
 
         if (unlikely(ZERO_OR_NULL_PTR(s)))
@@ -3234,9 +3183,9 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
 {
         struct kmem_cache *s;
 
-        if (unlikely(size > PAGE_SIZE / 2))
-                return (void *)__get_free_pages(gfpflags | __GFP_COMP,
-                                                        get_order(size));
+        if (unlikely(size > PAGE_SIZE))
+                return kmalloc_large(size, gfpflags);
+
         s = get_slab(size, gfpflags);
 
         if (unlikely(ZERO_OR_NULL_PTR(s)))