[RFC] SL[AUO]B common code 9/9] slabs: Extract a common function for kmem_cache_destroy

Christoph Lameter
2012-05-14T20:16:15Z

[-- Attachment #1: kmem_cache_destroy --]
[-- Type: text/plain, Size: 6831 bytes --]

kmem_cache_destroy does basically the same in all allocators.

Extract common code which is easy since we already have common mutex handling.

Signed-off-by: Christoph Lameter <cl@linux.com>

---
mm/slab.c | 55 +++----------------------------------------------------
mm/slab.h | 4 +++-
mm/slab_common.c | 22 ++++++++++++++++++++++
mm/slob.c | 11 +++++++----
mm/slub.c | 29 ++++++++---------------------
5 files changed, 43 insertions(+), 78 deletions(-)

Index: linux-2.6/mm/slab_common.c
===================================================================
--- linux-2.6.orig/mm/slab_common.c 2012-05-14 08:39:29.827145790 -0500
+++ linux-2.6/mm/slab_common.c 2012-05-14 08:39:42.867145519 -0500
@@ -113,6 +113,28 @@ out:
}
EXPORT_SYMBOL(kmem_cache_create);

+void kmem_cache_destroy(struct kmem_cache *s)
+{
+ get_online_cpus();
+ mutex_lock(&slab_mutex);
+ list_del(&s->list);
+
+ if (!__kmem_cache_shutdown(s)) {
+ if (s->flags & SLAB_DESTROY_BY_RCU)
+ rcu_barrier();
+
+ __kmem_cache_destroy(s);
+ } else {
+ list_add(&s->list, &slab_caches);
+ printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
+ s->name);
+ dump_stack();
+ }
+ mutex_unlock(&slab_mutex);
+ put_online_cpus();
+}
+EXPORT_SYMBOL(kmem_cache_destroy);
+
int slab_is_available(void)
{
return slab_state >= UP;
Index: linux-2.6/mm/slab.c
===================================================================
--- linux-2.6.orig/mm/slab.c 2012-05-14 08:39:29.831145790 -0500
+++ linux-2.6/mm/slab.c 2012-05-14 08:39:42.871145519 -0500
@@ -804,16 +804,6 @@ static void cache_estimate(unsigned long
*left_over = slab_size - nr_objs*buffer_size - mgmt_size;
}

-#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
-
-static void __slab_error(const char *function, struct kmem_cache *cachep,
- char *msg)
-{
- printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
- function, cachep->name, msg);
- dump_stack();
-}
-
/*
* By default on NUMA we use alien caches to stage the freeing of
* objects allocated from other nodes. This causes massive memory
@@ -2079,7 +2069,7 @@ static void slab_destroy(struct kmem_cac
}
}

-static void __kmem_cache_destroy(struct kmem_cache *cachep)
+void __kmem_cache_destroy(struct kmem_cache *cachep)
{
int i;
struct kmem_list3 *l3;
@@ -2635,49 +2625,10 @@ int kmem_cache_shrink(struct kmem_cache
}
EXPORT_SYMBOL(kmem_cache_shrink);

-/**
- * kmem_cache_destroy - delete a cache
- * @cachep: the cache to destroy
- *
- * Remove a &struct kmem_cache object from the slab cache.
- *
- * It is expected this function will be called by a module when it is
- * unloaded. This will remove the cache completely, and avoid a duplicate
- * cache being allocated each time a module is loaded and unloaded, if the
- * module doesn't have persistent in-kernel storage across loads and unloads.
- *
- * The cache must be empty before calling this function.
- *
- * The caller must guarantee that no one will allocate memory from the cache
- * during the kmem_cache_destroy().
- */
-void kmem_cache_destroy(struct kmem_cache *cachep)
+int __kmem_cache_shutdown(struct kmem_cache *cachep)
{
- BUG_ON(!cachep || in_interrupt());
-
- /* Find the cache in the chain of caches. */
- get_online_cpus();
- mutex_lock(&slab_mutex);
- /*
- * the chain is never empty, cache_cache is never destroyed
- */
- list_del(&cachep->list);
- if (__cache_shrink(cachep)) {
- slab_error(cachep, "Can't free all objects");
- list_add(&cachep->list, &slab_caches);
- mutex_unlock(&slab_mutex);
- put_online_cpus();
- return;
- }
-
- if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
- rcu_barrier();
-
- __kmem_cache_destroy(cachep);
- mutex_unlock(&slab_mutex);
- put_online_cpus();
+ return __cache_shrink(cachep);
}
-EXPORT_SYMBOL(kmem_cache_destroy);

/*
* Get the memory for a slab management obj.
Index: linux-2.6/mm/slab.h
===================================================================
--- linux-2.6.orig/mm/slab.h 2012-05-14 08:39:27.195145844 -0500
+++ linux-2.6/mm/slab.h 2012-05-14 08:39:42.871145519 -0500
@@ -30,5 +30,7 @@ extern struct list_head slab_caches;
struct kmem_cache *__kmem_cache_create (const char *name, size_t size,
size_t align, unsigned long flags, void (*ctor)(void *));

-#endif
+int __kmem_cache_shutdown(struct kmem_cache *);
+void __kmem_cache_destroy(struct kmem_cache *);

+#endif
Index: linux-2.6/mm/slob.c
===================================================================
--- linux-2.6.orig/mm/slob.c 2012-05-14 08:39:26.455145860 -0500
+++ linux-2.6/mm/slob.c 2012-05-14 08:39:42.871145519 -0500
@@ -570,14 +570,11 @@ struct kmem_cache *__kmem_cache_create(c
return c;
}

-void kmem_cache_destroy(struct kmem_cache *c)
+void __kmem_cache_destroy(struct kmem_cache *c)
{
kmemleak_free(c);
- if (c->flags & SLAB_DESTROY_BY_RCU)
- rcu_barrier();
slob_free(c, sizeof(struct kmem_cache));
}
-EXPORT_SYMBOL(kmem_cache_destroy);

void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
{
@@ -645,6 +642,12 @@ unsigned int kmem_cache_size(struct kmem
}
EXPORT_SYMBOL(kmem_cache_size);

+int __kmem_cache_shutdown(struct kmem_cache *c)
+{
+ /* No way to check for remaining objects */
+ return 0;
+}
+
int kmem_cache_shrink(struct kmem_cache *d)
{
return 0;
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2012-05-14 08:39:29.831145790 -0500
+++ linux-2.6/mm/slub.c 2012-05-14 08:39:42.871145519 -0500
@@ -3168,29 +3168,16 @@ static inline int kmem_cache_close(struc
return 0;
}

-/*
- * Close a cache and release the kmem_cache structure
- * (must be used for caches created using kmem_cache_create)
- */
-void kmem_cache_destroy(struct kmem_cache *s)
+int __kmem_cache_shutdown(struct kmem_cache *s)
{
- mutex_lock(&slab_mutex);
- s->refcount--;
- if (!s->refcount) {
- list_del(&s->list);
- mutex_unlock(&slab_mutex);
- if (kmem_cache_close(s)) {
- printk(KERN_ERR "SLUB %s: %s called for cache that "
- "still has objects.\n", s->name, __func__);
- dump_stack();
- }
- if (s->flags & SLAB_DESTROY_BY_RCU)
- rcu_barrier();
- sysfs_slab_remove(s);
- } else
- mutex_unlock(&slab_mutex);
+ return kmem_cache_close(s);
+}
+
+void __kmem_cache_destroy(struct kmem_cache *s)
+{
+ kfree(s);
+ sysfs_slab_remove(s);
}
-EXPORT_SYMBOL(kmem_cache_destroy);

/********************************************************************
* Kmalloc subsystem