mm, slub: allocate private object map for validate_slab_cache()

validate_slab_cache() is called either to handle a sysfs write, or from a
self-test context. In both situations it's straightforward to preallocate a
private object bitmap instead of grabbing the shared static one meant for
critical sections, so let's do that.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>

diff --git a/mm/slub.c b/mm/slub.c
index fb603fd..4697280 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4679,11 +4679,11 @@ static int count_total(struct page *page)
 #endif
 
 #ifdef CONFIG_SLUB_DEBUG
-static void validate_slab(struct kmem_cache *s, struct page *page)
+static void validate_slab(struct kmem_cache *s, struct page *page,
+                         unsigned long *obj_map)
 {
        void *p;
        void *addr = page_address(page);
-       unsigned long *map;
 
        slab_lock(page);
 
@@ -4691,21 +4691,20 @@ static void validate_slab(struct kmem_cache *s, struct page *page)
                goto unlock;
 
        /* Now we know that a valid freelist exists */
-       map = get_map(s, page);
+       __fill_map(obj_map, s, page);
        for_each_object(p, s, addr, page->objects) {
-               u8 val = test_bit(__obj_to_index(s, addr, p), map) ?
+               u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
                         SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
 
                if (!check_object(s, page, p, val))
                        break;
        }
-       put_map(map);
 unlock:
        slab_unlock(page);
 }
 
 static int validate_slab_node(struct kmem_cache *s,
-               struct kmem_cache_node *n)
+               struct kmem_cache_node *n, unsigned long *obj_map)
 {
        unsigned long count = 0;
        struct page *page;
@@ -4714,7 +4713,7 @@ static int validate_slab_node(struct kmem_cache *s,
        spin_lock_irqsave(&n->list_lock, flags);
 
        list_for_each_entry(page, &n->partial, slab_list) {
-               validate_slab(s, page);
+               validate_slab(s, page, obj_map);
                count++;
        }
        if (count != n->nr_partial) {
@@ -4727,7 +4726,7 @@ static int validate_slab_node(struct kmem_cache *s,
                goto out;
 
        list_for_each_entry(page, &n->full, slab_list) {
-               validate_slab(s, page);
+               validate_slab(s, page, obj_map);
                count++;
        }
        if (count != atomic_long_read(&n->nr_slabs)) {
@@ -4746,10 +4745,17 @@ long validate_slab_cache(struct kmem_cache *s)
        int node;
        unsigned long count = 0;
        struct kmem_cache_node *n;
+       unsigned long *obj_map;
+
+       obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
+       if (!obj_map)
+               return -ENOMEM;
 
        flush_all(s);
        for_each_kmem_cache_node(s, node, n)
-               count += validate_slab_node(s, n);
+               count += validate_slab_node(s, n, obj_map);
+
+       bitmap_free(obj_map);
 
        return count;
 }