1 files changed, 75 insertions, 9 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index dea145ed1868..204224d8e0d1 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -75,8 +75,8 @@ PLIST_HEAD(swap_active_head);
  * is held and the locking order requires swap_lock to be taken
  * before any swap_info_struct->lock.
  */
-static PLIST_HEAD(swap_avail_head);
-static DEFINE_SPINLOCK(swap_avail_lock);
+PLIST_HEAD(swap_avail_head);
+DEFINE_SPINLOCK(swap_avail_lock);
 
 struct swap_info_struct *swap_info[MAX_SWAPFILES];
 
@@ -91,6 +91,26 @@ static inline unsigned char swap_count(unsigned char ent)
 	return ent & ~SWAP_HAS_CACHE;	/* may include SWAP_HAS_CONT flag */
 }
 
+bool is_swap_fast(swp_entry_t entry)
+{
+	struct swap_info_struct *p;
+	unsigned long type;
+
+	if (non_swap_entry(entry))
+		return false;
+
+	type = swp_type(entry);
+	if (type >= nr_swapfiles)
+		return false;
+
+	p = swap_info[type];
+
+	if (p->flags & SWP_FAST)
+		return true;
+
+	return false;
+}
+
 /* returns 1 if swap entry is freed */
 static int
 __try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset)
@@ -193,7 +213,6 @@ static void discard_swap_cluster(struct swap_info_struct *si,
 	}
 }
 
-#define SWAPFILE_CLUSTER	256
 #define LATENCY_LIMIT		256
 
 static inline void cluster_set_flag(struct swap_cluster_info *info,
@@ -564,7 +583,7 @@ checks:
 		scan_base = offset = si->lowest_bit;
 
 	/* reuse swap entry of cache-only swap if not busy. */
-	if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+	if (vm_swap_full(si) && si->swap_map[offset] == SWAP_HAS_CACHE) {
 		int swap_was_freed;
 		spin_unlock(&si->lock);
 		swap_was_freed = __try_to_reclaim_swap(si, offset);
@@ -604,7 +623,8 @@ scan:
 			spin_lock(&si->lock);
 			goto checks;
 		}
-		if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+		if (vm_swap_full(si) &&
+			si->swap_map[offset] == SWAP_HAS_CACHE) {
 			spin_lock(&si->lock);
 			goto checks;
 		}
@@ -619,7 +639,8 @@ scan:
 			spin_lock(&si->lock);
 			goto checks;
 		}
-		if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+		if (vm_swap_full(si) &&
+			si->swap_map[offset] == SWAP_HAS_CACHE) {
 			spin_lock(&si->lock);
 			goto checks;
 		}
@@ -640,18 +661,39 @@ swp_entry_t get_swap_page(void)
 {
 	struct swap_info_struct *si, *next;
 	pgoff_t offset;
+	int swap_ratio_off = 0;
 
 	if (atomic_long_read(&nr_swap_pages) <= 0)
 		goto noswap;
 	atomic_long_dec(&nr_swap_pages);
 
+lock_and_start:
 	spin_lock(&swap_avail_lock);
 
 start_over:
 	plist_for_each_entry_safe(si, next, &swap_avail_head, avail_list) {
+
+		if (sysctl_swap_ratio && !swap_ratio_off) {
+			int ret;
+
+			spin_unlock(&swap_avail_lock);
+			ret = swap_ratio(&si);
+			if (0 > ret) {
+				/*
+				 * Error. Start again with swap
+				 * ratio disabled.
+				 */
+				swap_ratio_off = 1;
+				goto lock_and_start;
+			} else {
+				goto start;
+			}
+		}
+
 		/* requeue si to after same-priority siblings */
 		plist_requeue(&si->avail_list, &swap_avail_head);
 		spin_unlock(&swap_avail_lock);
+start:
 		spin_lock(&si->lock);
 		if (!si->highest_bit || !(si->flags & SWP_WRITEOK)) {
 			spin_lock(&swap_avail_lock);
@@ -932,11 +974,25 @@ int reuse_swap_page(struct page *page)
 	count = page_mapcount(page);
 	if (count <= 1 && PageSwapCache(page)) {
 		count += page_swapcount(page);
-		if (count == 1 && !PageWriteback(page)) {
+		if (count != 1)
+			goto out;
+		if (!PageWriteback(page)) {
 			delete_from_swap_cache(page);
 			SetPageDirty(page);
+		} else {
+			swp_entry_t entry;
+			struct swap_info_struct *p;
+
+			entry.val = page_private(page);
+			p = swap_info_get(entry);
+			if (p->flags & SWP_STABLE_WRITES) {
+				spin_unlock(&p->lock);
+				return false;
+			}
+			spin_unlock(&p->lock);
 		}
 	}
+out:
 	return count <= 1;
 }
 
@@ -1008,7 +1064,8 @@ int free_swap_and_cache(swp_entry_t entry)
 		 * Also recheck PageSwapCache now page is locked (above).
 		 */
 		if (PageSwapCache(page) && !PageWriteback(page) &&
-				(!page_mapped(page) || vm_swap_full())) {
+				(!page_mapped(page) ||
+				vm_swap_full(page_swap_info(page)))) {
 			delete_from_swap_cache(page);
 			SetPageDirty(page);
 		}
@@ -2481,6 +2538,10 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		error = -ENOMEM;
 		goto bad_swap;
 	}
+
+	if (bdi_cap_stable_pages_required(inode_to_bdi(inode)))
+		p->flags |= SWP_STABLE_WRITES;
+
 	if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) {
 		int cpu;
 
@@ -2553,11 +2614,16 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		}
 	}
 
+	if (p->bdev && blk_queue_fast(bdev_get_queue(p->bdev)))
+		p->flags |= SWP_FAST;
+
 	mutex_lock(&swapon_mutex);
 	prio = -1;
-	if (swap_flags & SWAP_FLAG_PREFER)
+	if (swap_flags & SWAP_FLAG_PREFER) {
 		prio =
 		  (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT;
+		setup_swap_ratio(p, prio);
+	}
 	enable_swap_info(p, prio, swap_map, cluster_info, frontswap_map);
 
 	pr_info("Adding %uk swap on %s.  Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",