From d8843922fba49e887874aa1f9e748d620c5092af Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Wed, 17 Oct 2012 15:36:51 +0400 Subject: [PATCH] slab: Ignore internal flags in cache creation Some flags are used internally by the allocators for management purposes. One example of that is the CFLGS_OFF_SLAB flag that slab uses to mark that the metadata for that cache is stored outside of the slab. No cache should ever pass those as a creation flags. We can just ignore this bit if it happens to be passed (such as when duplicating a cache in the kmem memcg patches). Because such flags can vary from allocator to allocator, we allow them to make their own decisions on that, defining SLAB_AVAILABLE_FLAGS with all flags that are valid at creation time. Allocators that doesn't have any specific flag requirement should define that to mean all flags. Common code will mask out all flags not belonging to that set. Acked-by: Christoph Lameter Acked-by: David Rientjes Signed-off-by: Glauber Costa Signed-off-by: Pekka Enberg --- mm/slab.c | 22 ---------------------- mm/slab.h | 25 +++++++++++++++++++++++++ mm/slab_common.c | 7 +++++++ mm/slub.c | 3 --- 4 files changed, 32 insertions(+), 25 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 1f7fd5f51f87..6ebb9515a3e9 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -162,23 +162,6 @@ */ static bool pfmemalloc_active __read_mostly; -/* Legal flag mask for kmem_cache_create(). */ -#if DEBUG -# define CREATE_MASK (SLAB_RED_ZONE | \ - SLAB_POISON | SLAB_HWCACHE_ALIGN | \ - SLAB_CACHE_DMA | \ - SLAB_STORE_USER | \ - SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ - SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ - SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) -#else -# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \ - SLAB_CACHE_DMA | \ - SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ - SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ - SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) -#endif - /* * kmem_bufctl_t: * @@ -2378,11 +2361,6 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) if (flags & SLAB_DESTROY_BY_RCU) BUG_ON(flags & SLAB_POISON); #endif - /* - * Always checks flags, a caller might be expecting debug support which - * isn't available. - */ - BUG_ON(flags & ~CREATE_MASK); /* * Check that size is in terms of words. This is needed to avoid diff --git a/mm/slab.h b/mm/slab.h index 5a43c2f13621..66a62d3536c6 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -45,6 +45,31 @@ static inline struct kmem_cache *__kmem_cache_alias(const char *name, size_t siz #endif +/* Legal flag mask for kmem_cache_create(), for various configurations */ +#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \ + SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS ) + +#if defined(CONFIG_DEBUG_SLAB) +#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) +#elif defined(CONFIG_SLUB_DEBUG) +#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ + SLAB_TRACE | SLAB_DEBUG_FREE) +#else +#define SLAB_DEBUG_FLAGS (0) +#endif + +#if defined(CONFIG_SLAB) +#define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \ + SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK) +#elif defined(CONFIG_SLUB) +#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \ + SLAB_TEMPORARY | SLAB_NOTRACK) +#else +#define SLAB_CACHE_FLAGS (0) +#endif + +#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS) + int __kmem_cache_shutdown(struct kmem_cache *); struct seq_file; diff --git a/mm/slab_common.c b/mm/slab_common.c index 5fb753da6cf0..b705be7faa48 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -109,6 +109,13 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align if (!kmem_cache_sanity_check(name, size) == 0) goto out_locked; + /* + * Some allocators will constraint the set of valid flags to a subset + * of all flags. We expect them to define CACHE_CREATE_MASK in this + * case, and we'll just provide them with a sanitized version of the + * passed flags. + */ + flags &= CACHE_CREATE_MASK; s = __kmem_cache_alias(name, size, align, flags, ctor); if (s) diff --git a/mm/slub.c b/mm/slub.c index deee7c754a7d..b2ada3db4225 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -112,9 +112,6 @@ * the fast path and disables lockless freelists. */ -#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ - SLAB_TRACE | SLAB_DEBUG_FREE) - static inline int kmem_cache_debug(struct kmem_cache *s) { #ifdef CONFIG_SLUB_DEBUG