diff --git a/mm/swap_ratio.c b/mm/swap_ratio.c
new file mode 100644
index 0000000..242cdf6
--- /dev/null
+++ b/mm/swap_ratio.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/mm_types.h>
+#include <linux/swapfile.h>
+#include <linux/swap.h>
+
+#define SWAP_RATIO_GROUP_START (SWAP_FLAG_PRIO_MASK - 9) /* 32758 */
+#define SWAP_RATIO_GROUP_END (SWAP_FLAG_PRIO_MASK) /* 32767 */
+#define SWAP_FAST_WRITES (SWAPFILE_CLUSTER * (SWAP_CLUSTER_MAX / 8))
+#define SWAP_SLOW_WRITES SWAPFILE_CLUSTER
+
+/*
+ * The fast/slow swap write ratio.
+ * 100 indicates that all writes should
+ * go to fast swap device.
+ */
+int sysctl_swap_ratio = 100;
+
+/* Enable the swap ratio feature */
+int sysctl_swap_ratio_enable;
+
+static bool is_same_group(struct swap_info_struct *a,
+		struct swap_info_struct *b)
+{
+	if (!sysctl_swap_ratio_enable)
+		return false;
+
+	if (!is_swap_ratio_group(a->prio))
+		return false;
+
+	if (a->prio == b->prio)
+		return true;
+
+	return false;
+}
+
+/* Caller must hold swap_avail_lock */
+static int calculate_write_pending(struct swap_info_struct *si,
+			struct swap_info_struct *n)
+{
+	int ratio = sysctl_swap_ratio;
+
+	if ((ratio < 0) || (ratio > 100))
+		return -EINVAL;
+
+	if (WARN_ON(!(si->flags & SWP_FAST)))
+		return -ENODEV;
+
+	if ((n->flags & SWP_FAST) || !is_same_group(si, n))
+		return -ENODEV;
+
+	si->max_writes = ratio ? SWAP_FAST_WRITES : 0;
+	n->max_writes  = ratio ? (SWAP_FAST_WRITES * 100) /
+			ratio - SWAP_FAST_WRITES : SWAP_SLOW_WRITES;
+
+	si->write_pending = si->max_writes;
+	n->write_pending = n->max_writes;
+
+	return 0;
+}
+
+static int swap_ratio_slow(struct swap_info_struct **si)
+{
+	struct swap_info_struct *n = NULL;
+	int ret = 0;
+
+	spin_lock(&(*si)->lock);
+	spin_lock(&swap_avail_lock);
+	if (&(*si)->avail_list == plist_last(&swap_avail_head)) {
+		/* just to make skip work */
+		n = *si;
+		ret = -ENODEV;
+		goto skip;
+	}
+	n = plist_next_entry(&(*si)->avail_list,
+			struct swap_info_struct,
+			avail_list);
+	spin_unlock(&swap_avail_lock);
+	spin_lock(&n->lock);
+	spin_lock(&swap_avail_lock);
+
+	if ((*si)->flags & SWP_FAST) {
+		if ((*si)->write_pending) {
+			(*si)->write_pending--;
+			goto exit;
+		} else {
+			if ((n->flags & SWP_FAST) || !is_same_group(*si, n)) {
+				/* Should never happen */
+				ret = -ENODEV;
+			} else if (n->write_pending) {
+				/*
+				 * Requeue fast device, since there are pending
+				 * writes for slow device.
+				 */
+				plist_requeue(&(*si)->avail_list,
+					&swap_avail_head);
+				n->write_pending--;
+				spin_unlock(&(*si)->lock);
+				*si = n;
+				goto skip;
+			} else {
+				if (calculate_write_pending(*si, n) < 0) {
+					ret = -ENODEV;
+					goto exit;
+				}
+				/* Restart from fast device */
+				(*si)->write_pending--;
+			}
+		}
+	} else {
+		if (!(n->flags & SWP_FAST) || !is_same_group(*si, n)) {
+			/* Should never happen */
+			ret = -ENODEV;
+		} else if (n->write_pending) {
+			/*
+			 * Pending writes for fast device.
+			 * We reach here when slow device is swapped on first,
+			 * before fast device.
+			 */
+			/* requeue slow device to the end */
+			plist_requeue(&(*si)->avail_list, &swap_avail_head);
+			n->write_pending--;
+			spin_unlock(&(*si)->lock);
+			*si = n;
+			goto skip;
+		} else {
+			if ((*si)->write_pending) {
+				(*si)->write_pending--;
+			} else {
+				if (calculate_write_pending(n, *si) < 0) {
+					ret = -ENODEV;
+					goto exit;
+				}
+				n->write_pending--;
+				plist_requeue(&(*si)->avail_list,
+					&swap_avail_head);
+				spin_unlock(&(*si)->lock);
+				*si = n;
+				goto skip;
+			}
+		}
+	}
+exit:
+	spin_unlock(&(*si)->lock);
+skip:
+	spin_unlock(&swap_avail_lock);
+	/* n and si would have got interchanged */
+	spin_unlock(&n->lock);
+	return ret;
+}
+
+bool is_swap_ratio_group(int prio)
+{
+	return ((prio >= SWAP_RATIO_GROUP_START) &&
+		(prio <= SWAP_RATIO_GROUP_END)) ? true : false;
+}
+
+void setup_swap_ratio(struct swap_info_struct *p, int prio)
+{
+	/* Used only if sysctl_swap_ratio_enable is set */
+	if (is_swap_ratio_group(prio)) {
+		if (p->flags & SWP_FAST)
+			p->write_pending = SWAP_FAST_WRITES;
+		else
+			p->write_pending = SWAP_SLOW_WRITES;
+		p->max_writes =  p->write_pending;
+	}
+}
+
+int swap_ratio(struct swap_info_struct **si)
+{
+	if (is_swap_ratio_group((*si)->prio))
+		return swap_ratio_slow(si);
+	else
+		return -ENODEV;
+}