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authorIngo Molnar <mingo@elte.hu>2006-07-03 00:25:28 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-03 15:27:09 -0700
commit2b2d5493e10051694ae3a57ea6a153e3cb4d4488 (patch)
treee44a89aa4d9c7c635770cb8891703f555d48b08d /mm
parent897c6ff9568bcb102ffc6b465ebe1def0cba829d (diff)
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[PATCH] lockdep: annotate SLAB code
Teach special (recursive) locking code to the lock validator. Has no effect on non-lockdep kernels. Fix initialize-locks-via-memcpy assumptions. Effects on non-lockdep kernels: the subclass nesting parameter is passed into cache_free_alien() and __cache_free(), and turns one internal kmem_cache_free() call into an open-coded __cache_free() call. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/slab.c59
1 files changed, 48 insertions, 11 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 3936af344542..85c2e03098a7 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1021,7 +1021,8 @@ static void drain_alien_cache(struct kmem_cache *cachep,
}
}
-static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
+static inline int cache_free_alien(struct kmem_cache *cachep, void *objp,
+ int nesting)
{
struct slab *slabp = virt_to_slab(objp);
int nodeid = slabp->nodeid;
@@ -1039,7 +1040,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
STATS_INC_NODEFREES(cachep);
if (l3->alien && l3->alien[nodeid]) {
alien = l3->alien[nodeid];
- spin_lock(&alien->lock);
+ spin_lock_nested(&alien->lock, nesting);
if (unlikely(alien->avail == alien->limit)) {
STATS_INC_ACOVERFLOW(cachep);
__drain_alien_cache(cachep, alien, nodeid);
@@ -1068,7 +1069,8 @@ static inline void free_alien_cache(struct array_cache **ac_ptr)
{
}
-static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
+static inline int cache_free_alien(struct kmem_cache *cachep, void *objp,
+ int nesting)
{
return 0;
}
@@ -1272,6 +1274,11 @@ static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
local_irq_disable();
memcpy(ptr, list, sizeof(struct kmem_list3));
+ /*
+ * Do not assume that spinlocks can be initialized via memcpy:
+ */
+ spin_lock_init(&ptr->list_lock);
+
MAKE_ALL_LISTS(cachep, ptr, nodeid);
cachep->nodelists[nodeid] = ptr;
local_irq_enable();
@@ -1398,7 +1405,7 @@ void __init kmem_cache_init(void)
}
/* 4) Replace the bootstrap head arrays */
{
- void *ptr;
+ struct array_cache *ptr;
ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
@@ -1406,6 +1413,11 @@ void __init kmem_cache_init(void)
BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
memcpy(ptr, cpu_cache_get(&cache_cache),
sizeof(struct arraycache_init));
+ /*
+ * Do not assume that spinlocks can be initialized via memcpy:
+ */
+ spin_lock_init(&ptr->lock);
+
cache_cache.array[smp_processor_id()] = ptr;
local_irq_enable();
@@ -1416,6 +1428,11 @@ void __init kmem_cache_init(void)
!= &initarray_generic.cache);
memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
sizeof(struct arraycache_init));
+ /*
+ * Do not assume that spinlocks can be initialized via memcpy:
+ */
+ spin_lock_init(&ptr->lock);
+
malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
ptr;
local_irq_enable();
@@ -1743,6 +1760,8 @@ static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
}
#endif
+static void __cache_free(struct kmem_cache *cachep, void *objp, int nesting);
+
/**
* slab_destroy - destroy and release all objects in a slab
* @cachep: cache pointer being destroyed
@@ -1766,8 +1785,17 @@ static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
call_rcu(&slab_rcu->head, kmem_rcu_free);
} else {
kmem_freepages(cachep, addr);
- if (OFF_SLAB(cachep))
- kmem_cache_free(cachep->slabp_cache, slabp);
+ if (OFF_SLAB(cachep)) {
+ unsigned long flags;
+
+ /*
+ * lockdep: we may nest inside an already held
+ * ac->lock, so pass in a nesting flag:
+ */
+ local_irq_save(flags);
+ __cache_free(cachep->slabp_cache, slabp, 1);
+ local_irq_restore(flags);
+ }
}
}
@@ -3072,7 +3100,16 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
if (slabp->inuse == 0) {
if (l3->free_objects > l3->free_limit) {
l3->free_objects -= cachep->num;
+ /*
+ * It is safe to drop the lock. The slab is
+ * no longer linked to the cache. cachep
+ * cannot disappear - we are using it and
+ * all destruction of caches must be
+ * serialized properly by the user.
+ */
+ spin_unlock(&l3->list_lock);
slab_destroy(cachep, slabp);
+ spin_lock(&l3->list_lock);
} else {
list_add(&slabp->list, &l3->slabs_free);
}
@@ -3098,7 +3135,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
#endif
check_irq_off();
l3 = cachep->nodelists[node];
- spin_lock(&l3->list_lock);
+ spin_lock_nested(&l3->list_lock, SINGLE_DEPTH_NESTING);
if (l3->shared) {
struct array_cache *shared_array = l3->shared;
int max = shared_array->limit - shared_array->avail;
@@ -3141,14 +3178,14 @@ free_done:
* Release an obj back to its cache. If the obj has a constructed state, it must
* be in this state _before_ it is released. Called with disabled ints.
*/
-static inline void __cache_free(struct kmem_cache *cachep, void *objp)
+static void __cache_free(struct kmem_cache *cachep, void *objp, int nesting)
{
struct array_cache *ac = cpu_cache_get(cachep);
check_irq_off();
objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
- if (cache_free_alien(cachep, objp))
+ if (cache_free_alien(cachep, objp, nesting))
return;
if (likely(ac->avail < ac->limit)) {
@@ -3387,7 +3424,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
BUG_ON(virt_to_cache(objp) != cachep);
local_irq_save(flags);
- __cache_free(cachep, objp);
+ __cache_free(cachep, objp, 0);
local_irq_restore(flags);
}
EXPORT_SYMBOL(kmem_cache_free);
@@ -3412,7 +3449,7 @@ void kfree(const void *objp)
kfree_debugcheck(objp);
c = virt_to_cache(objp);
debug_check_no_locks_freed(objp, obj_size(c));
- __cache_free(c, (void *)objp);
+ __cache_free(c, (void *)objp, 0);
local_irq_restore(flags);
}
EXPORT_SYMBOL(kfree);