slub: enable tracking of full slabs

If slab tracking is on then build a list of full slabs so that we can verify
the integrity of all slabs and are also able to built list of alloc/free
callers.

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>

2 files changed, 41 insertions, 1 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f8e0c86c48a9..ea27065e80e6 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -16,6 +16,7 @@ struct kmem_cache_node {
         unsigned long nr_partial;
         atomic_long_t nr_slabs;
         struct list_head partial;
+        struct list_head full;
 };
 
 /*
diff --git a/mm/slub.c b/mm/slub.c
index cfc5301afe42..c4f40d373d1e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -661,6 +661,40 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
         return search == NULL;
 }
 
+/*
+ * Tracking of fully allocated slabs for debugging
+ */
+static void add_full(struct kmem_cache *s, struct page *page)
+{
+        struct kmem_cache_node *n;
+
+        VM_BUG_ON(!irqs_disabled());
+
+        VM_BUG_ON(!irqs_disabled());
+
+        if (!(s->flags & SLAB_STORE_USER))
+                return;
+
+        n = get_node(s, page_to_nid(page));
+        spin_lock(&n->list_lock);
+        list_add(&page->lru, &n->full);
+        spin_unlock(&n->list_lock);
+}
+
+static void remove_full(struct kmem_cache *s, struct page *page)
+{
+        struct kmem_cache_node *n;
+
+        if (!(s->flags & SLAB_STORE_USER))
+                return;
+
+        n = get_node(s, page_to_nid(page));
+
+        spin_lock(&n->list_lock);
+        list_del(&page->lru);
+        spin_unlock(&n->list_lock);
+}
+
 static int alloc_object_checks(struct kmem_cache *s, struct page *page,
                                                         void *object)
 {
@@ -1090,6 +1124,8 @@ static void putback_slab(struct kmem_cache *s, struct page *page)
         if (page->inuse) {
                 if (page->freelist)
                         add_partial(s, page);
+                else if (PageError(page))
+                        add_full(s, page);
                 slab_unlock(page);
         } else {
                 slab_unlock(page);
@@ -1302,7 +1338,7 @@ out_unlock:
 slab_empty:
         if (prior)
                 /*
-                 * Partially used slab that is on the partial list.
+                 * Slab on the partial list.
                  */
                 remove_partial(s, page);
 
@@ -1314,6 +1350,8 @@ slab_empty:
 debug:
         if (!free_object_checks(s, page, x))
                 goto out_unlock;
+        if (!PageActive(page) && !page->freelist)
+                remove_full(s, page);
         if (s->flags & SLAB_STORE_USER)
                 set_track(s, x, TRACK_FREE, addr);
         goto checks_ok;
@@ -1466,6 +1504,7 @@ static void init_kmem_cache_node(struct kmem_cache_node *n)
         atomic_long_set(&n->nr_slabs, 0);
         spin_lock_init(&n->list_lock);
         INIT_LIST_HEAD(&n->partial);
+        INIT_LIST_HEAD(&n->full);
 }
 
 #ifdef CONFIG_NUMA