diff options
| -rw-r--r-- | mm/slub.c | 43 |
1 files changed, 38 insertions, 5 deletions
@@ -211,6 +211,8 @@ 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 @@ -1539,7 +1541,6 @@ load_freelist: unlock_out: slab_unlock(c->page); stat(c, ALLOC_SLOWPATH); -out: #ifdef SLUB_FASTPATH local_irq_restore(flags); #endif @@ -1574,8 +1575,24 @@ new_slab: c->page = new; goto load_freelist; } - object = NULL; - goto out; +#ifdef SLUB_FASTPATH + local_irq_restore(flags); +#endif + /* + * 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)) @@ -2322,7 +2339,20 @@ 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; @@ -2539,7 +2569,7 @@ 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); @@ -3058,6 +3088,9 @@ 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; |
