SLUB: Simplify debug code

Consolidate functionality into the #ifdef section.

Extract tracing into one subroutine.

Move object debug processing into the #ifdef section so that the
code in __slab_alloc and __slab_free becomes minimal.

Reduce number of functions we need to provide stubs for in the !SLUB_DEBUG case.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 57 insertions, 55 deletions

diff --git a/mm/slub.c b/mm/slub.c
index e7ad123bb6a7..98801d404d69 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -742,6 +742,22 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
         return search == NULL;
 }
 
+static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc)
+{
+        if (s->flags & SLAB_TRACE) {
+                printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
+                        s->name,
+                        alloc ? "alloc" : "free",
+                        object, page->inuse,
+                        page->freelist);
+
+                if (!alloc)
+                        print_section("Object", (void *)object, s->objsize);
+
+                dump_stack();
+        }
+}
+
 /*
  * Tracking of fully allocated slabs for debugging purposes.
  */
@@ -766,8 +782,18 @@ static void remove_full(struct kmem_cache *s, struct page *page)
         spin_unlock(&n->list_lock);
 }
 
-static int alloc_object_checks(struct kmem_cache *s, struct page *page,
-                                                        void *object)
+static void setup_object_debug(struct kmem_cache *s, struct page *page,
+                                                                void *object)
+{
+        if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
+                return;
+
+        init_object(s, object, 0);
+        init_tracking(s, object);
+}
+
+static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
+                                                void *object, void *addr)
 {
         if (!check_slab(s, page))
                 goto bad;
@@ -782,13 +808,16 @@ static int alloc_object_checks(struct kmem_cache *s, struct page *page,
                 goto bad;
         }
 
-        if (!object)
-                return 1;
-
-        if (!check_object(s, page, object, 0))
+        if (object && !check_object(s, page, object, 0))
                 goto bad;
 
+        /* Success perform special debug activities for allocs */
+        if (s->flags & SLAB_STORE_USER)
+                set_track(s, object, TRACK_ALLOC, addr);
+        trace(s, page, object, 1);
+        init_object(s, object, 1);
         return 1;
+
 bad:
         if (PageSlab(page)) {
                 /*
@@ -806,8 +835,8 @@ bad:
         return 0;
 }
 
-static int free_object_checks(struct kmem_cache *s, struct page *page,
-                                                        void *object)
+static int free_debug_processing(struct kmem_cache *s, struct page *page,
+                                                void *object, void *addr)
 {
         if (!check_slab(s, page))
                 goto fail;
@@ -841,29 +870,22 @@ static int free_object_checks(struct kmem_cache *s, struct page *page,
                                 "to slab %s", object, page->slab->name);
                 goto fail;
         }
+
+        /* Special debug activities for freeing objects */
+        if (!SlabFrozen(page) && !page->freelist)
+                remove_full(s, page);
+        if (s->flags & SLAB_STORE_USER)
+                set_track(s, object, TRACK_FREE, addr);
+        trace(s, page, object, 0);
+        init_object(s, object, 0);
         return 1;
+
 fail:
         printk(KERN_ERR "@@@ SLUB: %s slab 0x%p object at 0x%p not freed.\n",
                 s->name, page, object);
         return 0;
 }
 
-static void trace(struct kmem_cache *s, struct page *page, void *object, int alloc)
-{
-        if (s->flags & SLAB_TRACE) {
-                printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
-                        s->name,
-                        alloc ? "alloc" : "free",
-                        object, page->inuse,
-                        page->freelist);
-
-                if (!alloc)
-                        print_section("Object", (void *)object, s->objsize);
-
-                dump_stack();
-        }
-}
-
 static int __init setup_slub_debug(char *str)
 {
         if (!str || *str != '=')
@@ -932,26 +954,20 @@ static void kmem_cache_open_debug_check(struct kmem_cache *s)
                                 s->flags |= slub_debug;
 }
 #else
+static inline void setup_object_debug(struct kmem_cache *s,
+                        struct page *page, void *object) {}
 
-static inline int alloc_object_checks(struct kmem_cache *s,
-                struct page *page, void *object) { return 0; }
+static inline int alloc_debug_processing(struct kmem_cache *s,
+        struct page *page, void *object, void *addr) { return 0; }
 
-static inline int free_object_checks(struct kmem_cache *s,
-                struct page *page, void *object) { return 0; }
+static inline int free_debug_processing(struct kmem_cache *s,
+        struct page *page, void *object, void *addr) { return 0; }
 
-static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
-static inline void remove_full(struct kmem_cache *s, struct page *page) {}
-static inline void trace(struct kmem_cache *s, struct page *page,
-                        void *object, int alloc) {}
-static inline void init_object(struct kmem_cache *s,
-                        void *object, int active) {}
-static inline void init_tracking(struct kmem_cache *s, void *object) {}
 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
                         { return 1; }
 static inline int check_object(struct kmem_cache *s, struct page *page,
                         void *object, int active) { return 1; }
-static inline void set_track(struct kmem_cache *s, void *object,
-                        enum track_item alloc, void *addr) {}
+static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
 static inline void kmem_cache_open_debug_check(struct kmem_cache *s) {}
 #define slub_debug 0
 #endif
@@ -988,11 +1004,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 static void setup_object(struct kmem_cache *s, struct page *page,
                                 void *object)
 {
-        if (SlabDebug(page)) {
-                init_object(s, object, 0);
-                init_tracking(s, object);
-        }
-
+        setup_object_debug(s, page, object);
         if (unlikely(s->ctor))
                 s->ctor(object, s, 0);
 }
@@ -1449,12 +1461,8 @@ new_slab:
         return NULL;
 debug:
         object = page->freelist;
-        if (!alloc_object_checks(s, page, object))
+        if (!alloc_debug_processing(s, page, object, addr))
                 goto another_slab;
-        if (s->flags & SLAB_STORE_USER)
-                set_track(s, object, TRACK_ALLOC, addr);
-        trace(s, page, object, 1);
-        init_object(s, object, 1);
 
         page->inuse++;
         page->freelist = object[page->offset];
@@ -1561,14 +1569,8 @@ slab_empty:
         return;
 
 debug:
-        if (!free_object_checks(s, page, x))
+        if (!free_debug_processing(s, page, x, addr))
                 goto out_unlock;
-        if (!SlabFrozen(page) && !page->freelist)
-                remove_full(s, page);
-        if (s->flags & SLAB_STORE_USER)
-                set_track(s, x, TRACK_FREE, addr);
-        trace(s, page, object, 0);
-        init_object(s, object, 0);
         goto checks_ok;
 }
 
@@ -1805,7 +1807,7 @@ static struct kmem_cache_node * __init early_kmem_cache_node_alloc(gfp_t gfpflag
         page->freelist = get_freepointer(kmalloc_caches, n);
         page->inuse++;
         kmalloc_caches->node[node] = n;
-        init_object(kmalloc_caches, n, 1);
+        setup_object_debug(kmalloc_caches, page, n);
         init_kmem_cache_node(n);
         atomic_long_inc(&n->nr_slabs);
         add_partial(n, page);