1 files changed, 116 insertions, 168 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 4f4e6472db5b..863c005a3d9c 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -169,12 +169,6 @@ typedef unsigned short freelist_idx_t;
 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
 
 /*
- * true if a page was allocated from pfmemalloc reserves for network-based
- * swap
- */
-static bool pfmemalloc_active __read_mostly;
-
-/*
  * struct array_cache
  *
  * Purpose:
@@ -195,10 +189,6 @@ struct array_cache {
 			 * Must have this definition in here for the proper
 			 * alignment of array_cache. Also simplifies accessing
 			 * the entries.
-			 *
-			 * Entries should not be directly dereferenced as
-			 * entries belonging to slabs marked pfmemalloc will
-			 * have the lower bits set SLAB_OBJ_PFMEMALLOC
 			 */
 };
 
@@ -207,23 +197,6 @@ struct alien_cache {
 	struct array_cache ac;
 };
 
-#define SLAB_OBJ_PFMEMALLOC	1
-static inline bool is_obj_pfmemalloc(void *objp)
-{
-	return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
-}
-
-static inline void set_obj_pfmemalloc(void **objp)
-{
-	*objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
-	return;
-}
-
-static inline void clear_obj_pfmemalloc(void **objp)
-{
-	*objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
-}
-
 /*
  * Need this for bootstrapping a per node allocator.
  */
@@ -623,120 +596,21 @@ static struct array_cache *alloc_arraycache(int node, int entries,
 	return ac;
 }
 
-static inline bool is_slab_pfmemalloc(struct page *page)
-{
-	return PageSlabPfmemalloc(page);
-}
-
-/* Clears pfmemalloc_active if no slabs have pfmalloc set */
-static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
-						struct array_cache *ac)
-{
-	struct kmem_cache_node *n = get_node(cachep, numa_mem_id());
-	struct page *page;
-	unsigned long flags;
-
-	if (!pfmemalloc_active)
-		return;
-
-	spin_lock_irqsave(&n->list_lock, flags);
-	list_for_each_entry(page, &n->slabs_full, lru)
-		if (is_slab_pfmemalloc(page))
-			goto out;
-
-	list_for_each_entry(page, &n->slabs_partial, lru)
-		if (is_slab_pfmemalloc(page))
-			goto out;
-
-	list_for_each_entry(page, &n->slabs_free, lru)
-		if (is_slab_pfmemalloc(page))
-			goto out;
-
-	pfmemalloc_active = false;
-out:
-	spin_unlock_irqrestore(&n->list_lock, flags);
-}
-
-static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
-						gfp_t flags, bool force_refill)
+static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
+					struct page *page, void *objp)
 {
-	int i;
-	void *objp = ac->entry[--ac->avail];
-
-	/* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
-	if (unlikely(is_obj_pfmemalloc(objp))) {
-		struct kmem_cache_node *n;
-
-		if (gfp_pfmemalloc_allowed(flags)) {
-			clear_obj_pfmemalloc(&objp);
-			return objp;
-		}
-
-		/* The caller cannot use PFMEMALLOC objects, find another one */
-		for (i = 0; i < ac->avail; i++) {
-			/* If a !PFMEMALLOC object is found, swap them */
-			if (!is_obj_pfmemalloc(ac->entry[i])) {
-				objp = ac->entry[i];
-				ac->entry[i] = ac->entry[ac->avail];
-				ac->entry[ac->avail] = objp;
-				return objp;
-			}
-		}
-
-		/*
-		 * If there are empty slabs on the slabs_free list and we are
-		 * being forced to refill the cache, mark this one !pfmemalloc.
-		 */
-		n = get_node(cachep, numa_mem_id());
-		if (!list_empty(&n->slabs_free) && force_refill) {
-			struct page *page = virt_to_head_page(objp);
-			ClearPageSlabPfmemalloc(page);
-			clear_obj_pfmemalloc(&objp);
-			recheck_pfmemalloc_active(cachep, ac);
-			return objp;
-		}
-
-		/* No !PFMEMALLOC objects available */
-		ac->avail++;
-		objp = NULL;
-	}
-
-	return objp;
-}
-
-static inline void *ac_get_obj(struct kmem_cache *cachep,
-			struct array_cache *ac, gfp_t flags, bool force_refill)
-{
-	void *objp;
-
-	if (unlikely(sk_memalloc_socks()))
-		objp = __ac_get_obj(cachep, ac, flags, force_refill);
-	else
-		objp = ac->entry[--ac->avail];
-
-	return objp;
-}
-
-static noinline void *__ac_put_obj(struct kmem_cache *cachep,
-			struct array_cache *ac, void *objp)
-{
-	if (unlikely(pfmemalloc_active)) {
-		/* Some pfmemalloc slabs exist, check if this is one */
-		struct page *page = virt_to_head_page(objp);
-		if (PageSlabPfmemalloc(page))
-			set_obj_pfmemalloc(&objp);
-	}
+	struct kmem_cache_node *n;
+	int page_node;
+	LIST_HEAD(list);
 
-	return objp;
-}
+	page_node = page_to_nid(page);
+	n = get_node(cachep, page_node);
 
-static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
-								void *objp)
-{
-	if (unlikely(sk_memalloc_socks()))
-		objp = __ac_put_obj(cachep, ac, objp);
+	spin_lock(&n->list_lock);
+	free_block(cachep, &objp, 1, page_node, &list);
+	spin_unlock(&n->list_lock);
 
-	ac->entry[ac->avail++] = objp;
+	slabs_destroy(cachep, &list);
 }
 
 /*
@@ -939,7 +813,7 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
 			STATS_INC_ACOVERFLOW(cachep);
 			__drain_alien_cache(cachep, ac, page_node, &list);
 		}
-		ac_put_obj(cachep, ac, objp);
+		ac->entry[ac->avail++] = objp;
 		spin_unlock(&alien->lock);
 		slabs_destroy(cachep, &list);
 	} else {
@@ -1540,10 +1414,6 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 		return NULL;
 	}
 
-	/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
-	if (page_is_pfmemalloc(page))
-		pfmemalloc_active = true;
-
 	nr_pages = (1 << cachep->gfporder);
 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
 		add_zone_page_state(page_zone(page),
@@ -1551,8 +1421,10 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 	else
 		add_zone_page_state(page_zone(page),
 			NR_SLAB_UNRECLAIMABLE, nr_pages);
+
 	__SetPageSlab(page);
-	if (page_is_pfmemalloc(page))
+	/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
+	if (sk_memalloc_socks() && page_is_pfmemalloc(page))
 		SetPageSlabPfmemalloc(page);
 
 	if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
@@ -2823,7 +2695,46 @@ static inline void fixup_slab_list(struct kmem_cache *cachep,
 		list_add(&page->lru, &n->slabs_partial);
 }
 
-static struct page *get_first_slab(struct kmem_cache_node *n)
+/* Try to find non-pfmemalloc slab if needed */
+static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
+					struct page *page, bool pfmemalloc)
+{
+	if (!page)
+		return NULL;
+
+	if (pfmemalloc)
+		return page;
+
+	if (!PageSlabPfmemalloc(page))
+		return page;
+
+	/* No need to keep pfmemalloc slab if we have enough free objects */
+	if (n->free_objects > n->free_limit) {
+		ClearPageSlabPfmemalloc(page);
+		return page;
+	}
+
+	/* Move pfmemalloc slab to the end of list to speed up next search */
+	list_del(&page->lru);
+	if (!page->active)
+		list_add_tail(&page->lru, &n->slabs_free);
+	else
+		list_add_tail(&page->lru, &n->slabs_partial);
+
+	list_for_each_entry(page, &n->slabs_partial, lru) {
+		if (!PageSlabPfmemalloc(page))
+			return page;
+	}
+
+	list_for_each_entry(page, &n->slabs_free, lru) {
+		if (!PageSlabPfmemalloc(page))
+			return page;
+	}
+
+	return NULL;
+}
+
+static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
 {
 	struct page *page;
 
@@ -2835,11 +2746,41 @@ static struct page *get_first_slab(struct kmem_cache_node *n)
 				struct page, lru);
 	}
 
+	if (sk_memalloc_socks())
+		return get_valid_first_slab(n, page, pfmemalloc);
+
 	return page;
 }
 
-static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
-							bool force_refill)
+static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
+				struct kmem_cache_node *n, gfp_t flags)
+{
+	struct page *page;
+	void *obj;
+	void *list = NULL;
+
+	if (!gfp_pfmemalloc_allowed(flags))
+		return NULL;
+
+	spin_lock(&n->list_lock);
+	page = get_first_slab(n, true);
+	if (!page) {
+		spin_unlock(&n->list_lock);
+		return NULL;
+	}
+
+	obj = slab_get_obj(cachep, page);
+	n->free_objects--;
+
+	fixup_slab_list(cachep, n, page, &list);
+
+	spin_unlock(&n->list_lock);
+	fixup_objfreelist_debug(cachep, &list);
+
+	return obj;
+}
+
+static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 {
 	int batchcount;
 	struct kmem_cache_node *n;
@@ -2849,8 +2790,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
 
 	check_irq_off();
 	node = numa_mem_id();
-	if (unlikely(force_refill))
-		goto force_grow;
+
 retry:
 	ac = cpu_cache_get(cachep);
 	batchcount = ac->batchcount;
@@ -2876,7 +2816,7 @@ retry:
 	while (batchcount > 0) {
 		struct page *page;
 		/* Get slab alloc is to come from. */
-		page = get_first_slab(n);
+		page = get_first_slab(n, false);
 		if (!page)
 			goto must_grow;
 
@@ -2894,7 +2834,7 @@ retry:
 			STATS_INC_ACTIVE(cachep);
 			STATS_SET_HIGH(cachep);
 
-			ac_put_obj(cachep, ac, slab_get_obj(cachep, page));
+			ac->entry[ac->avail++] = slab_get_obj(cachep, page);
 		}
 
 		fixup_slab_list(cachep, n, page, &list);
@@ -2908,7 +2848,15 @@ alloc_done:
 
 	if (unlikely(!ac->avail)) {
 		int x;
-force_grow:
+
+		/* Check if we can use obj in pfmemalloc slab */
+		if (sk_memalloc_socks()) {
+			void *obj = cache_alloc_pfmemalloc(cachep, n, flags);
+
+			if (obj)
+				return obj;
+		}
+
 		x = cache_grow(cachep, gfp_exact_node(flags), node, NULL);
 
 		/* cache_grow can reenable interrupts, then ac could change. */
@@ -2916,7 +2864,7 @@ force_grow:
 		node = numa_mem_id();
 
 		/* no objects in sight? abort */
-		if (!x && (ac->avail == 0 || force_refill))
+		if (!x && ac->avail == 0)
 			return NULL;
 
 		if (!ac->avail)		/* objects refilled by interrupt? */
@@ -2924,7 +2872,7 @@ force_grow:
 	}
 	ac->touched = 1;
 
-	return ac_get_obj(cachep, ac, flags, force_refill);
+	return ac->entry[--ac->avail];
 }
 
 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
@@ -2982,28 +2930,20 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 {
 	void *objp;
 	struct array_cache *ac;
-	bool force_refill = false;
 
 	check_irq_off();
 
 	ac = cpu_cache_get(cachep);
 	if (likely(ac->avail)) {
 		ac->touched = 1;
-		objp = ac_get_obj(cachep, ac, flags, false);
+		objp = ac->entry[--ac->avail];
 
-		/*
-		 * Allow for the possibility all avail objects are not allowed
-		 * by the current flags
-		 */
-		if (objp) {
-			STATS_INC_ALLOCHIT(cachep);
-			goto out;
-		}
-		force_refill = true;
+		STATS_INC_ALLOCHIT(cachep);
+		goto out;
 	}
 
 	STATS_INC_ALLOCMISS(cachep);
-	objp = cache_alloc_refill(cachep, flags, force_refill);
+	objp = cache_alloc_refill(cachep, flags);
 	/*
 	 * the 'ac' may be updated by cache_alloc_refill(),
 	 * and kmemleak_erase() requires its correct value.
@@ -3151,7 +3091,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 retry:
 	check_irq_off();
 	spin_lock(&n->list_lock);
-	page = get_first_slab(n);
+	page = get_first_slab(n, false);
 	if (!page)
 		goto must_grow;
 
@@ -3304,7 +3244,6 @@ static void free_block(struct kmem_cache *cachep, void **objpp,
 		void *objp;
 		struct page *page;
 
-		clear_obj_pfmemalloc(&objpp[i]);
 		objp = objpp[i];
 
 		page = virt_to_head_page(objp);
@@ -3410,7 +3349,16 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp,
 		cache_flusharray(cachep, ac);
 	}
 
-	ac_put_obj(cachep, ac, objp);
+	if (sk_memalloc_socks()) {
+		struct page *page = virt_to_head_page(objp);
+
+		if (unlikely(PageSlabPfmemalloc(page))) {
+			cache_free_pfmemalloc(cachep, page, objp);
+			return;
+		}
+	}
+
+	ac->entry[ac->avail++] = objp;
 }
 
 /**