[PATCH 2/2] slab: move kmem_cache_free to common code

[Glauber Costa <glommer@parallels.com>]

In the effort of commonizing the slab allocators, it would be better if
we had a single entry-point for kmem_cache_free. The low-level freeing
is still left to the allocators, But at least the tracing can be done in
slab_common.c

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@kernel.org>
CC: David Rientjes <rientjes@google.com>

---
 mm/slab.c        | 13 +------------
 mm/slab.h        |  1 +
 mm/slab_common.c | 17 +++++++++++++++++
 mm/slob.c        | 11 ++++-------
 mm/slub.c        |  5 +----
 5 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 98b3460..b8171ab 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3903,15 +3903,7 @@ void *__kmalloc(size_t size, gfp_t flags)
 EXPORT_SYMBOL(__kmalloc);
 #endif
 
-/**
- * kmem_cache_free - Deallocate an object
- * @cachep: The cache the allocation was from.
- * @objp: The previously allocated object.
- *
- * Free an object which was previously allocated from this
- * cache.
- */
-void kmem_cache_free(struct kmem_cache *cachep, void *objp)
+void __kmem_cache_free(struct kmem_cache *cachep, void *objp)
 {
 	unsigned long flags;
 
@@ -3921,10 +3913,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 		debug_check_no_obj_freed(objp, cachep->object_size);
 	__cache_free(cachep, objp, __builtin_return_address(0));
 	local_irq_restore(flags);
-
-	trace_kmem_cache_free(_RET_IP_, objp);
 }
-EXPORT_SYMBOL(kmem_cache_free);
 
 /**
  * kfree - free previously allocated memory
diff --git a/mm/slab.h b/mm/slab.h
index 66a62d3..dc1024f 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -34,6 +34,7 @@ extern struct kmem_cache *kmem_cache;
 
 /* Functions provided by the slab allocators */
 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
+extern void __kmem_cache_free(struct kmem_cache *s, void *x);
 
 #ifdef CONFIG_SLUB
 struct kmem_cache *__kmem_cache_alias(const char *name, size_t size,
diff --git a/mm/slab_common.c b/mm/slab_common.c
index bf4b4f1..3b9d5c5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -19,6 +19,8 @@
 #include <asm/tlbflush.h>
 #include <asm/page.h>
 
+#include <trace/events/kmem.h>
+
 #include "slab.h"
 
 enum slab_state slab_state;
@@ -168,6 +170,21 @@ out_locked:
 }
 EXPORT_SYMBOL(kmem_cache_create);
 
+/**
+ * kmem_cache_free - Deallocate an object
+ * @cachep: The cache the allocation was from.
+ * @objp: The previously allocated object.
+ *
+ * Free an object which was previously allocated from this
+ * cache.
+ */
+void kmem_cache_free(struct kmem_cache *s, void *x)
+{
+	__kmem_cache_free(s, x);
+	trace_kmem_cache_free(_RET_IP_, x);
+}
+EXPORT_SYMBOL(kmem_cache_free);
+
 void kmem_cache_destroy(struct kmem_cache *s)
 {
 	get_online_cpus();
diff --git a/mm/slob.c b/mm/slob.c
index 3edfeaa..d131f75 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -555,7 +555,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 }
 EXPORT_SYMBOL(kmem_cache_alloc_node);
 
-static void __kmem_cache_free(void *b, int size)
+static void do_kmem_cache_free(void *b, int size)
 {
 	if (size < PAGE_SIZE)
 		slob_free(b, size);
@@ -568,10 +568,10 @@ static void kmem_rcu_free(struct rcu_head *head)
 	struct slob_rcu *slob_rcu = (struct slob_rcu *)head;
 	void *b = (void *)slob_rcu - (slob_rcu->size - sizeof(struct slob_rcu));
 
-	__kmem_cache_free(b, slob_rcu->size);
+	do_kmem_cache_free(b, slob_rcu->size);
 }
 
-void kmem_cache_free(struct kmem_cache *c, void *b)
+void __kmem_cache_free(struct kmem_cache *c, void *b)
 {
 	kmemleak_free_recursive(b, c->flags);
 	if (unlikely(c->flags & SLAB_DESTROY_BY_RCU)) {
@@ -580,12 +580,9 @@ void kmem_cache_free(struct kmem_cache *c, void *b)
 		slob_rcu->size = c->size;
 		call_rcu(&slob_rcu->head, kmem_rcu_free);
 	} else {
-		__kmem_cache_free(b, c->size);
+		do_kmem_cache_free(b, c->size);
 	}
-
-	trace_kmem_cache_free(_RET_IP_, b);
 }
-EXPORT_SYMBOL(kmem_cache_free);
 
 unsigned int kmem_cache_size(struct kmem_cache *c)
 {
diff --git a/mm/slub.c b/mm/slub.c
index 259bc2c..0c512de 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2606,7 +2606,7 @@ redo:
 
 }
 
-void kmem_cache_free(struct kmem_cache *s, void *x)
+void __kmem_cache_free(struct kmem_cache *s, void *x)
 {
 	struct page *page;
 
@@ -2620,10 +2620,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	}
 
 	slab_free(s, page, x, _RET_IP_);
-
-	trace_kmem_cache_free(_RET_IP_, x);
 }
-EXPORT_SYMBOL(kmem_cache_free);
 
 /*
  * Object placement in a slab is made very easy because we always start at
-- 
1.7.11.7

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