mm: slab/slub: use page->list consistently instead of page->lru

'struct page' has two list_head fields: 'lru' and 'list'.  Conveniently,
they are unioned together.  This means that code can use them
interchangably, which gets horribly confusing like with this nugget from
slab.c:

>	list_del(&page->lru);
>	if (page->active == cachep->num)
>		list_add(&page->list, &n->slabs_full);

This patch makes the slab and slub code use page->lru universally instead
of mixing ->list and ->lru.

So, the new rule is: page->lru is what the you use if you want to keep
your page on a list.  Don't like the fact that it's not called ->list?
Too bad.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 290901a8c1de..84b74080beb7 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -124,6 +124,8 @@ struct page {
         union {
                 struct list_head lru;   /* Pageout list, eg. active_list
                                          * protected by zone->lru_lock !
+                                         * Can be used as a generic list
+                                         * by the page owner.
                                          */
                 struct {                /* slub per cpu partial pages */
                         struct page *next;      /* Next partial slab */
@@ -136,7 +138,6 @@ struct page {
 #endif
                 };
 
-                struct list_head list;  /* slobs list of pages */
                 struct slab *slab_page; /* slab fields */
                 struct rcu_head rcu_head;       /* Used by SLAB
                                                  * when destroying via RCU