mm/slub: remove dead code for debug caches on deactivate_slab()

After commit c7323a5ad0786 ("mm/slub: restrict sysfs validation to debug
caches and make it safe"), SLUB never installs percpu slab for debug caches
and thus never deactivates percpu slab for them.

Since only debug caches use the full list, SLUB no longer deactivates to
full list. Remove dead code in deactivate_slab().

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/mm/slub.c b/mm/slub.c
index 157527d..5eea9e4 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2411,7 +2411,7 @@ static void init_kmem_cache_cpus(struct kmem_cache *s)
 static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
                            void *freelist)
 {
-       enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE, M_FULL_NOLIST };
+       enum slab_modes { M_NONE, M_PARTIAL, M_FREE, M_FULL_NOLIST };
        struct kmem_cache_node *n = get_node(s, slab_nid(slab));
        int free_delta = 0;
        enum slab_modes mode = M_NONE;
@@ -2487,14 +2487,6 @@ redo:
                 * acquire_slab() will see a slab that is frozen
                 */
                spin_lock_irqsave(&n->list_lock, flags);
-       } else if (kmem_cache_debug_flags(s, SLAB_STORE_USER)) {
-               mode = M_FULL;
-               /*
-                * This also ensures that the scanning of full
-                * slabs from diagnostic functions will not see
-                * any frozen slabs.
-                */
-               spin_lock_irqsave(&n->list_lock, flags);
        } else {
                mode = M_FULL_NOLIST;
        }
@@ -2504,7 +2496,7 @@ redo:
                                old.freelist, old.counters,
                                new.freelist, new.counters,
                                "unfreezing slab")) {
-               if (mode == M_PARTIAL || mode == M_FULL)
+               if (mode == M_PARTIAL)
                        spin_unlock_irqrestore(&n->list_lock, flags);
                goto redo;
        }
@@ -2518,10 +2510,6 @@ redo:
                stat(s, DEACTIVATE_EMPTY);
                discard_slab(s, slab);
                stat(s, FREE_SLAB);
-       } else if (mode == M_FULL) {
-               add_full(s, n, slab);
-               spin_unlock_irqrestore(&n->list_lock, flags);
-               stat(s, DEACTIVATE_FULL);
        } else if (mode == M_FULL_NOLIST) {
                stat(s, DEACTIVATE_FULL);
        }