slub: use slab_list instead of lru

Currently we use the page->lru list for maintaining lists of slabs.  We
have a list in the page structure (slab_list) that can be used for this
purpose.  Doing so makes the code cleaner since we are not overloading the
lru list.

Use the slab_list instead of the lru list for maintaining lists of slabs.

Link: http://lkml.kernel.org/r/20190402230545.2929-6-tobin@kernel.orgSigned-off-by: Tobin C. Harding <tobin@kernel.org>
Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -1014,7 +1014,7 @@ static void add_full(struct kmem_cache *s,
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_add(&page->lru, &n->full);
+	list_add(&page->slab_list, &n->full);
 }
 
 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
@@ -1023,7 +1023,7 @@ static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->lru);
+	list_del(&page->slab_list);
 }
 
 /* Tracking of the number of slabs for debugging purposes */
@@ -1764,9 +1764,9 @@ __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
 {
 	n->nr_partial++;
 	if (tail == DEACTIVATE_TO_TAIL)
-		list_add_tail(&page->lru, &n->partial);
+		list_add_tail(&page->slab_list, &n->partial);
 	else
-		list_add(&page->lru, &n->partial);
+		list_add(&page->slab_list, &n->partial);
 }
 
 static inline void add_partial(struct kmem_cache_node *n,
@@ -1780,7 +1780,7 @@ static inline void remove_partial(struct kmem_cache_node *n,
 					struct page *page)
 {
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->lru);
+	list_del(&page->slab_list);
 	n->nr_partial--;
 }
 
@@ -1854,7 +1854,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 		return NULL;
 
 	spin_lock(&n->list_lock);
-	list_for_each_entry_safe(page, page2, &n->partial, lru) {
+	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
 		void *t;
 
 		if (!pfmemalloc_match(page, flags))
@@ -2398,7 +2398,7 @@ static unsigned long count_partial(struct kmem_cache_node *n,
 	struct page *page;
 
 	spin_lock_irqsave(&n->list_lock, flags);
-	list_for_each_entry(page, &n->partial, lru)
+	list_for_each_entry(page, &n->partial, slab_list)
 		x += get_count(page);
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	return x;
@@ -3696,10 +3696,10 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 
 	BUG_ON(irqs_disabled());
 	spin_lock_irq(&n->list_lock);
-	list_for_each_entry_safe(page, h, &n->partial, lru) {
+	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
 		if (!page->inuse) {
 			remove_partial(n, page);
-			list_add(&page->lru, &discard);
+			list_add(&page->slab_list, &discard);
 		} else {
 			list_slab_objects(s, page,
 			"Objects remaining in %s on __kmem_cache_shutdown()");
@@ -3707,7 +3707,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 	}
 	spin_unlock_irq(&n->list_lock);
 
-	list_for_each_entry_safe(page, h, &discard, lru)
+	list_for_each_entry_safe(page, h, &discard, slab_list)
 		discard_slab(s, page);
 }
 
@@ -3987,7 +3987,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		 * Note that concurrent frees may occur while we hold the
 		 * list_lock. page->inuse here is the upper limit.
 		 */
-		list_for_each_entry_safe(page, t, &n->partial, lru) {
+		list_for_each_entry_safe(page, t, &n->partial, slab_list) {
 			int free = page->objects - page->inuse;
 
 			/* Do not reread page->inuse */
@@ -3997,10 +3997,10 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 			BUG_ON(free <= 0);
 
 			if (free == page->objects) {
-				list_move(&page->lru, &discard);
+				list_move(&page->slab_list, &discard);
 				n->nr_partial--;
 			} else if (free <= SHRINK_PROMOTE_MAX)
-				list_move(&page->lru, promote + free - 1);
+				list_move(&page->slab_list, promote + free - 1);
 		}
 
 		/*
@@ -4013,7 +4013,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		spin_unlock_irqrestore(&n->list_lock, flags);
 
 		/* Release empty slabs */
-		list_for_each_entry_safe(page, t, &discard, lru)
+		list_for_each_entry_safe(page, t, &discard, slab_list)
 			discard_slab(s, page);
 
 		if (slabs_node(s, node))
@@ -4205,11 +4205,11 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	for_each_kmem_cache_node(s, node, n) {
 		struct page *p;
 
-		list_for_each_entry(p, &n->partial, lru)
+		list_for_each_entry(p, &n->partial, slab_list)
 			p->slab_cache = s;
 
 #ifdef CONFIG_SLUB_DEBUG
-		list_for_each_entry(p, &n->full, lru)
+		list_for_each_entry(p, &n->full, slab_list)
 			p->slab_cache = s;
 #endif
 	}
@@ -4426,7 +4426,7 @@ static int validate_slab_node(struct kmem_cache *s,
 
 	spin_lock_irqsave(&n->list_lock, flags);
 
-	list_for_each_entry(page, &n->partial, lru) {
+	list_for_each_entry(page, &n->partial, slab_list) {
 		validate_slab_slab(s, page, map);
 		count++;
 	}
@@ -4437,7 +4437,7 @@ static int validate_slab_node(struct kmem_cache *s,
 	if (!(s->flags & SLAB_STORE_USER))
 		goto out;
 
-	list_for_each_entry(page, &n->full, lru) {
+	list_for_each_entry(page, &n->full, slab_list) {
 		validate_slab_slab(s, page, map);
 		count++;
 	}
@@ -4633,9 +4633,9 @@ static int list_locations(struct kmem_cache *s, char *buf,
 			continue;
 
 		spin_lock_irqsave(&n->list_lock, flags);
-		list_for_each_entry(page, &n->partial, lru)
+		list_for_each_entry(page, &n->partial, slab_list)
 			process_slab(&t, s, page, alloc, map);
-		list_for_each_entry(page, &n->full, lru)
+		list_for_each_entry(page, &n->full, slab_list)
 			process_slab(&t, s, page, alloc, map);
 		spin_unlock_irqrestore(&n->list_lock, flags);
 	}