[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 <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/slab.c b/mm/slab.c
index 3233c4c..2b37a62 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -674,6 +674,8 @@
#endif
};
+#define BAD_ALIEN_MAGIC 0x01020304ul
+
#ifdef CONFIG_LOCKDEP
/*
@@ -682,29 +684,53 @@
* 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(struct cache_sizes *s)
+static inline void init_lock_keys(void)
+
{
int q;
+ struct cache_sizes *s = malloc_sizes;
- 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);
+ 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 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 @@
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 @@
mutex_unlock(&cache_chain_mutex);
}
+ /* Annotate slab for lockdep -- annotate the malloc caches */
+ init_lock_keys();
+
+
/* Done! */
g_cpucache_up = FULL;