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diff --git a/src/third_party/wiredtiger/src/include/capacity.h b/src/third_party/wiredtiger/src/include/capacity.h
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index 00000000000..1fb42f5b435
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+++ b/src/third_party/wiredtiger/src/include/capacity.h
@@ -0,0 +1,74 @@
+/*-
+ * Copyright (c) 2014-2019 MongoDB, Inc.
+ * Copyright (c) 2008-2014 WiredTiger, Inc.
+ *	All rights reserved.
+ *
+ * See the file LICENSE for redistribution information.
+ */
+
+typedef enum {
+	WT_THROTTLE_CKPT,		/* Checkpoint throttle */
+	WT_THROTTLE_EVICT,		/* Eviction throttle */
+	WT_THROTTLE_LOG,		/* Logging throttle */
+	WT_THROTTLE_READ		/* Read throttle */
+} WT_THROTTLE_TYPE;
+
+#define	WT_THROTTLE_MIN	WT_MEGABYTE	/* Config minimum size */
+
+/*
+ * The per-file threshold means we won't start the background fsync on a file
+ * until it crosses the per-file threshold of data written. The other minimum
+ * threshold defines a minimum threshold for the background thread. Otherwise
+ * we compute a percentage of the given capacity.
+ */
+#define	WT_CAPACITY_FILE_THRESHOLD	(WT_MEGABYTE / 2)
+#define	WT_CAPACITY_MIN_THRESHOLD	(10 * WT_MEGABYTE)
+#define	WT_CAPACITY_PCT			10
+
+/*
+ * If we're being asked to sleep a short amount of time, ignore it.
+ * A non-zero value means there may be a temporary violation of the
+ * capacity limitation, but one that would even out. That is, possibly
+ * fewer sleeps with the risk of more choppy behavior as this number
+ * is larger.
+ */
+#define	WT_CAPACITY_SLEEP_CUTOFF_US	100
+
+/*
+ * When given a total capacity, divide it up for each subsystem. These defines
+ * represent the percentage of the total capacity that we allow for each
+ * subsystem capacity. We allow and expect the sum of the subsystems to
+ * exceed 100, as often they are not at their maximum at the same time. In any
+ * event, we track the total capacity separately, so it is never exceeded.
+ */
+#define	WT_CAPACITY_SYS(total, pct)	((total) * (pct) / 100)
+#define	WT_CAP_CKPT		5
+#define	WT_CAP_EVICT		50
+#define	WT_CAP_LOG		30
+#define	WT_CAP_READ		55
+
+struct __wt_capacity {
+	uint64_t ckpt;			/* Bytes/sec checkpoint capacity */
+	uint64_t evict;			/* Bytes/sec eviction capacity */
+	uint64_t log;			/* Bytes/sec logging capacity */
+	uint64_t read;			/* Bytes/sec read capacity */
+	uint64_t total;			/* Bytes/sec total capacity */
+	uint64_t threshold;		/* Capacity size period */
+
+	volatile uint64_t	written;	/* Written this period */
+	volatile bool		signalled;	/* Capacity signalled */
+
+	/*
+	 * A reservation is a point in time when a read or write for a subsystem
+	 * can be scheduled, so as not to overrun the given capacity.  These
+	 * values hold the next available reservation, in nanoseconds since
+	 * the epoch. Getting a reservation with a future time implies sleeping
+	 * until that time; getting a reservation with a past time implies that
+	 * the operation can be done immediately.
+	 */
+	uint64_t reservation_ckpt;	/* Atomic: next checkpoint write */
+	uint64_t reservation_evict;	/* Atomic: next eviction write */
+	uint64_t reservation_log;	/* Atomic: next logging write */
+	uint64_t reservation_read;	/* Atomic: next read */
+	uint64_t reservation_total;	/* Atomic: next operation of any kind */
+};