From 056c62418cc639bf2fe962c6a6ee56054b838bc7 Mon Sep 17 00:00:00 2001 From: Ravikiran G Thirumalai Date: Mon, 25 Sep 2006 23:31:38 -0700 Subject: [PATCH] [PATCH] slab: fix lockdep warnings Place the alien array cache locks of on slab malloc slab caches on a seperate lockdep class. This avoids false positives from lockdep [akpm@osdl.org: build fix] Signed-off-by: Ravikiran Thirumalai Signed-off-by: Shai Fultheim Cc: Thomas Gleixner Acked-by: Arjan van de Ven Cc: Ingo Molnar Cc: Pekka Enberg Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 57 +++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 43 insertions(+), 14 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 3233c4c7cbce..2b37a62f6314 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -674,6 +674,8 @@ static struct kmem_cache cache_cache = { #endif }; +#define BAD_ALIEN_MAGIC 0x01020304ul + #ifdef CONFIG_LOCKDEP /* @@ -682,29 +684,53 @@ static struct kmem_cache cache_cache = { * The locking for this is tricky in that it nests within the locks * of all other slabs in a few places; to deal with this special * locking we put on-slab caches into a separate lock-class. + * + * We set lock class for alien array caches which are up during init. + * The lock annotation will be lost if all cpus of a node goes down and + * then comes back up during hotplug */ -static struct lock_class_key on_slab_key; +static struct lock_class_key on_slab_l3_key; +static struct lock_class_key on_slab_alc_key; + +static inline void init_lock_keys(void) -static inline void init_lock_keys(struct cache_sizes *s) { int q; - - for (q = 0; q < MAX_NUMNODES; q++) { - if (!s->cs_cachep->nodelists[q] || OFF_SLAB(s->cs_cachep)) - continue; - lockdep_set_class(&s->cs_cachep->nodelists[q]->list_lock, - &on_slab_key); + struct cache_sizes *s = malloc_sizes; + + while (s->cs_size != ULONG_MAX) { + for_each_node(q) { + struct array_cache **alc; + int r; + struct kmem_list3 *l3 = s->cs_cachep->nodelists[q]; + if (!l3 || OFF_SLAB(s->cs_cachep)) + continue; + lockdep_set_class(&l3->list_lock, &on_slab_l3_key); + alc = l3->alien; + /* + * FIXME: This check for BAD_ALIEN_MAGIC + * should go away when common slab code is taught to + * work even without alien caches. + * Currently, non NUMA code returns BAD_ALIEN_MAGIC + * for alloc_alien_cache, + */ + if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC) + continue; + for_each_node(r) { + if (alc[r]) + lockdep_set_class(&alc[r]->lock, + &on_slab_alc_key); + } + } + s++; } } - #else -static inline void init_lock_keys(struct cache_sizes *s) +static inline void init_lock_keys(void) { } #endif - - /* Guard access to the cache-chain. */ static DEFINE_MUTEX(cache_chain_mutex); static struct list_head cache_chain; @@ -1091,7 +1117,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) static inline struct array_cache **alloc_alien_cache(int node, int limit) { - return (struct array_cache **) 0x01020304ul; + return (struct array_cache **)BAD_ALIEN_MAGIC; } static inline void free_alien_cache(struct array_cache **ac_ptr) @@ -1421,7 +1447,6 @@ void __init kmem_cache_init(void) ARCH_KMALLOC_FLAGS|SLAB_PANIC, NULL, NULL); } - init_lock_keys(sizes); sizes->cs_dmacachep = kmem_cache_create(names->name_dma, sizes->cs_size, @@ -1495,6 +1520,10 @@ void __init kmem_cache_init(void) mutex_unlock(&cache_chain_mutex); } + /* Annotate slab for lockdep -- annotate the malloc caches */ + init_lock_keys(); + + /* Done! */ g_cpucache_up = FULL; -- 2.20.1