diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 6223f485f7e1..aff812631c40 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1425,6 +1425,100 @@ IO Interface Files
 	  8:16 rbytes=1459200 wbytes=314773504 rios=192 wios=353 dbytes=0 dios=0
 	  8:0 rbytes=90430464 wbytes=299008000 rios=8950 wios=1252 dbytes=50331648 dios=3021
 
+  io.cost.qos
+	A read-write nested-keyed file with exists only on the root
+	cgroup.
+
+	This file configures the Quality of Service of the IO cost
+	model based controller (CONFIG_BLK_CGROUP_IOCOST) which
+	currently implements "io.weight" proportional control.  Lines
+	are keyed by $MAJ:$MIN device numbers and not ordered.  The
+	line for a given device is populated on the first write for
+	the device on "io.cost.qos" or "io.cost.model".  The following
+	nested keys are defined.
+
+	  ======	=====================================
+	  enable	Weight-based control enable
+	  ctrl		"auto" or "user"
+	  rpct		Read latency percentile    [0, 100]
+	  rlat		Read latency threshold
+	  wpct		Write latency percentile   [0, 100]
+	  wlat		Write latency threshold
+	  min		Minimum scaling percentage [1, 10000]
+	  max		Maximum scaling percentage [1, 10000]
+	  ======	=====================================
+
+	The controller is disabled by default and can be enabled by
+	setting "enable" to 1.  "rpct" and "wpct" parameters default
+	to zero and the controller uses internal device saturation
+	state to adjust the overall IO rate between "min" and "max".
+
+	When a better control quality is needed, latency QoS
+	parameters can be configured.  For example::
+
+	  8:16 enable=1 ctrl=auto rpct=95.00 rlat=75000 wpct=95.00 wlat=150000 min=50.00 max=150.0
+
+	shows that on sdb, the controller is enabled, will consider
+	the device saturated if the 95th percentile of read completion
+	latencies is above 75ms or write 150ms, and adjust the overall
+	IO issue rate between 50% and 150% accordingly.
+
+	The lower the saturation point, the better the latency QoS at
+	the cost of aggregate bandwidth.  The narrower the allowed
+	adjustment range between "min" and "max", the more conformant
+	to the cost model the IO behavior.  Note that the IO issue
+	base rate may be far off from 100% and setting "min" and "max"
+	blindly can lead to a significant loss of device capacity or
+	control quality.  "min" and "max" are useful for regulating
+	devices which show wide temporary behavior changes - e.g. a
+	ssd which accepts writes at the line speed for a while and
+	then completely stalls for multiple seconds.
+
+	When "ctrl" is "auto", the parameters are controlled by the
+	kernel and may change automatically.  Setting "ctrl" to "user"
+	or setting any of the percentile and latency parameters puts
+	it into "user" mode and disables the automatic changes.  The
+	automatic mode can be restored by setting "ctrl" to "auto".
+
+  io.cost.model
+	A read-write nested-keyed file with exists only on the root
+	cgroup.
+
+	This file configures the cost model of the IO cost model based
+	controller (CONFIG_BLK_CGROUP_IOCOST) which currently
+	implements "io.weight" proportional control.  Lines are keyed
+	by $MAJ:$MIN device numbers and not ordered.  The line for a
+	given device is populated on the first write for the device on
+	"io.cost.qos" or "io.cost.model".  The following nested keys
+	are defined.
+
+	  =====		================================
+	  ctrl		"auto" or "user"
+	  model		The cost model in use - "linear"
+	  =====		================================
+
+	When "ctrl" is "auto", the kernel may change all parameters
+	dynamically.  When "ctrl" is set to "user" or any other
+	parameters are written to, "ctrl" become "user" and the
+	automatic changes are disabled.
+
+	When "model" is "linear", the following model parameters are
+	defined.
+
+	  =============	========================================
+	  [r|w]bps	The maximum sequential IO throughput
+	  [r|w]seqiops	The maximum 4k sequential IOs per second
+	  [r|w]randiops	The maximum 4k random IOs per second
+	  =============	========================================
+
+	From the above, the builtin linear model determines the base
+	costs of a sequential and random IO and the cost coefficient
+	for the IO size.  While simple, this model can cover most
+	common device classes acceptably.
+
+	The IO cost model isn't expected to be accurate in absolute
+	sense and is scaled to the device behavior dynamically.
+
   io.weight
 	A read-write flat-keyed file which exists on non-root cgroups.
 	The default is "default 100".
diff --git a/block/Kconfig b/block/Kconfig
index 56cb1695cd87..be1b82d94425 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -132,6 +132,15 @@ config BLK_CGROUP_IOLATENCY
 
 	Note, this is an experimental interface and could be changed someday.
 
+config BLK_CGROUP_IOCOST
+	bool "Enable support for cost model based cgroup IO controller"
+	depends on BLK_CGROUP=y
+	---help---
+	Enabling this option enables the .weight interface for cost
+	model based proportional IO control.  The IO controller
+	distributes IO capacity between different groups based on
+	their share of the overall weight distribution.
+
 config BLK_WBT_MQ
 	bool "Multiqueue writeback throttling"
 	default y
diff --git a/block/Makefile b/block/Makefile
index eee1b4ceecf9..9ef57ace90d4 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_BLK_DEV_BSGLIB)	+= bsg-lib.o
 obj-$(CONFIG_BLK_CGROUP)	+= blk-cgroup.o
 obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_BLK_CGROUP_IOLATENCY)	+= blk-iolatency.o
+obj-$(CONFIG_BLK_CGROUP_IOCOST)	+= blk-iocost.o
 obj-$(CONFIG_MQ_IOSCHED_DEADLINE)	+= mq-deadline.o
 obj-$(CONFIG_MQ_IOSCHED_KYBER)	+= kyber-iosched.o
 bfq-y				:= bfq-iosched.o bfq-wf2q.o bfq-cgroup.o
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
new file mode 100644
index 000000000000..1f697e5729f6
--- /dev/null
+++ b/block/blk-iocost.c
@@ -0,0 +1,2370 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * IO cost model based controller.
+ *
+ * Copyright (C) 2019 Tejun Heo <tj@kernel.org>
+ * Copyright (C) 2019 Andy Newell <newella@fb.com>
+ * Copyright (C) 2019 Facebook
+ *
+ * One challenge of controlling IO resources is the lack of trivially
+ * observable cost metric.  This is distinguished from CPU and memory where
+ * wallclock time and the number of bytes can serve as accurate enough
+ * approximations.
+ *
+ * Bandwidth and iops are the most commonly used metrics for IO devices but
+ * depending on the type and specifics of the device, different IO patterns
+ * easily lead to multiple orders of magnitude variations rendering them
+ * useless for the purpose of IO capacity distribution.  While on-device
+ * time, with a lot of clutches, could serve as a useful approximation for
+ * non-queued rotational devices, this is no longer viable with modern
+ * devices, even the rotational ones.
+ *
+ * While there is no cost metric we can trivially observe, it isn't a
+ * complete mystery.  For example, on a rotational device, seek cost
+ * dominates while a contiguous transfer contributes a smaller amount
+ * proportional to the size.  If we can characterize at least the relative
+ * costs of these different types of IOs, it should be possible to
+ * implement a reasonable work-conserving proportional IO resource
+ * distribution.
+ *
+ * 1. IO Cost Model
+ *
+ * IO cost model estimates the cost of an IO given its basic parameters and
+ * history (e.g. the end sector of the last IO).  The cost is measured in
+ * device time.  If a given IO is estimated to cost 10ms, the device should
+ * be able to process ~100 of those IOs in a second.
+ *
+ * Currently, there's only one builtin cost model - linear.  Each IO is
+ * classified as sequential or random and given a base cost accordingly.
+ * On top of that, a size cost proportional to the length of the IO is
+ * added.  While simple, this model captures the operational
+ * characteristics of a wide varienty of devices well enough.  Default
+ * paramters for several different classes of devices are provided and the
+ * parameters can be configured from userspace via
+ * /sys/fs/cgroup/io.cost.model.
+ *
+ * If needed, tools/cgroup/iocost_coef_gen.py can be used to generate
+ * device-specific coefficients.
+ *
+ * 2. Control Strategy
+ *
+ * The device virtual time (vtime) is used as the primary control metric.
+ * The control strategy is composed of the following three parts.
+ *
+ * 2-1. Vtime Distribution
+ *
+ * When a cgroup becomes active in terms of IOs, its hierarchical share is
+ * calculated.  Please consider the following hierarchy where the numbers
+ * inside parentheses denote the configured weights.
+ *
+ *           root
+ *         /       \
+ *      A (w:100)  B (w:300)
+ *      /       \
+ *  A0 (w:100)  A1 (w:100)
+ *
+ * If B is idle and only A0 and A1 are actively issuing IOs, as the two are
+ * of equal weight, each gets 50% share.  If then B starts issuing IOs, B
+ * gets 300/(100+300) or 75% share, and A0 and A1 equally splits the rest,
+ * 12.5% each.  The distribution mechanism only cares about these flattened
+ * shares.  They're called hweights (hierarchical weights) and always add
+ * upto 1 (HWEIGHT_WHOLE).
+ *
+ * A given cgroup's vtime runs slower in inverse proportion to its hweight.
+ * For example, with 12.5% weight, A0's time runs 8 times slower (100/12.5)
+ * against the device vtime - an IO which takes 10ms on the underlying
+ * device is considered to take 80ms on A0.
+ *
+ * This constitutes the basis of IO capacity distribution.  Each cgroup's
+ * vtime is running at a rate determined by its hweight.  A cgroup tracks
+ * the vtime consumed by past IOs and can issue a new IO iff doing so
+ * wouldn't outrun the current device vtime.  Otherwise, the IO is
+ * suspended until the vtime has progressed enough to cover it.
+ *
+ * 2-2. Vrate Adjustment
+ *
+ * It's unrealistic to expect the cost model to be perfect.  There are too
+ * many devices and even on the same device the overall performance
+ * fluctuates depending on numerous factors such as IO mixture and device
+ * internal garbage collection.  The controller needs to adapt dynamically.
+ *
+ * This is achieved by adjusting the overall IO rate according to how busy
+ * the device is.  If the device becomes overloaded, we're sending down too
+ * many IOs and should generally slow down.  If there are waiting issuers
+ * but the device isn't saturated, we're issuing too few and should
+ * generally speed up.
+ *
+ * To slow down, we lower the vrate - the rate at which the device vtime
+ * passes compared to the wall clock.  For example, if the vtime is running
+ * at the vrate of 75%, all cgroups added up would only be able to issue
+ * 750ms worth of IOs per second, and vice-versa for speeding up.
+ *
+ * Device business is determined using two criteria - rq wait and
+ * completion latencies.
+ *
+ * When a device gets saturated, the on-device and then the request queues
+ * fill up and a bio which is ready to be issued has to wait for a request
+ * to become available.  When this delay becomes noticeable, it's a clear
+ * indication that the device is saturated and we lower the vrate.  This
+ * saturation signal is fairly conservative as it only triggers when both
+ * hardware and software queues are filled up, and is used as the default
+ * busy signal.
+ *
+ * As devices can have deep queues and be unfair in how the queued commands
+ * are executed, soley depending on rq wait may not result in satisfactory
+ * control quality.  For a better control quality, completion latency QoS
+ * parameters can be configured so that the device is considered saturated
+ * if N'th percentile completion latency rises above the set point.
+ *
+ * The completion latency requirements are a function of both the
+ * underlying device characteristics and the desired IO latency quality of
+ * service.  There is an inherent trade-off - the tighter the latency QoS,
+ * the higher the bandwidth lossage.  Latency QoS is disabled by default
+ * and can be set through /sys/fs/cgroup/io.cost.qos.
+ *
+ * 2-3. Work Conservation
+ *
+ * Imagine two cgroups A and B with equal weights.  A is issuing a small IO
+ * periodically while B is sending out enough parallel IOs to saturate the
+ * device on its own.  Let's say A's usage amounts to 100ms worth of IO
+ * cost per second, i.e., 10% of the device capacity.  The naive
+ * distribution of half and half would lead to 60% utilization of the
+ * device, a significant reduction in the total amount of work done
+ * compared to free-for-all competition.  This is too high a cost to pay
+ * for IO control.
+ *
+ * To conserve the total amount of work done, we keep track of how much
+ * each active cgroup is actually using and yield part of its weight if
+ * there are other cgroups which can make use of it.  In the above case,
+ * A's weight will be lowered so that it hovers above the actual usage and
+ * B would be able to use the rest.
+ *
+ * As we don't want to penalize a cgroup for donating its weight, the
+ * surplus weight adjustment factors in a margin and has an immediate
+ * snapback mechanism in case the cgroup needs more IO vtime for itself.
+ *
+ * Note that adjusting down surplus weights has the same effects as
+ * accelerating vtime for other cgroups and work conservation can also be
+ * implemented by adjusting vrate dynamically.  However, squaring who can
+ * donate and should take back how much requires hweight propagations
+ * anyway making it easier to implement and understand as a separate
+ * mechanism.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/time64.h>
+#include <linux/parser.h>
+#include <linux/sched/signal.h>
+#include <linux/blk-cgroup.h>
+#include "blk-rq-qos.h"
+#include "blk-stat.h"
+#include "blk-wbt.h"
+
+#ifdef CONFIG_TRACEPOINTS
+
+/* copied from TRACE_CGROUP_PATH, see cgroup-internal.h */
+#define TRACE_IOCG_PATH_LEN 1024
+static DEFINE_SPINLOCK(trace_iocg_path_lock);
+static char trace_iocg_path[TRACE_IOCG_PATH_LEN];
+
+#define TRACE_IOCG_PATH(type, iocg, ...)					\
+	do {									\
+		unsigned long flags;						\
+		if (trace_iocost_##type##_enabled()) {				\
+			spin_lock_irqsave(&trace_iocg_path_lock, flags);	\
+			cgroup_path(iocg_to_blkg(iocg)->blkcg->css.cgroup,	\
+				    trace_iocg_path, TRACE_IOCG_PATH_LEN);	\
+			trace_iocost_##type(iocg, trace_iocg_path,		\
+					      ##__VA_ARGS__);			\
+			spin_unlock_irqrestore(&trace_iocg_path_lock, flags);	\
+		}								\
+	} while (0)
+
+#else	/* CONFIG_TRACE_POINTS */
+#define TRACE_IOCG_PATH(type, iocg, ...)	do { } while (0)
+#endif	/* CONFIG_TRACE_POINTS */
+
+enum {
+	MILLION			= 1000000,
+
+	/* timer period is calculated from latency requirements, bound it */
+	MIN_PERIOD		= USEC_PER_MSEC,
+	MAX_PERIOD		= USEC_PER_SEC,
+
+	/*
+	 * A cgroup's vtime can run 50% behind the device vtime, which
+	 * serves as its IO credit buffer.  Surplus weight adjustment is
+	 * immediately canceled if the vtime margin runs below 10%.
+	 */
+	MARGIN_PCT		= 50,
+	INUSE_MARGIN_PCT	= 10,
+
+	/* Have some play in waitq timer operations */
+	WAITQ_TIMER_MARGIN_PCT	= 5,
+
+	/*
+	 * vtime can wrap well within a reasonable uptime when vrate is
+	 * consistently raised.  Don't trust recorded cgroup vtime if the
+	 * period counter indicates that it's older than 5mins.
+	 */
+	VTIME_VALID_DUR		= 300 * USEC_PER_SEC,
+
+	/*
+	 * Remember the past three non-zero usages and use the max for
+	 * surplus calculation.  Three slots guarantee that we remember one
+	 * full period usage from the last active stretch even after
+	 * partial deactivation and re-activation periods.  Don't start
+	 * giving away weight before collecting two data points to prevent
+	 * hweight adjustments based on one partial activation period.
+	 */
+	NR_USAGE_SLOTS		= 3,
+	MIN_VALID_USAGES	= 2,
+
+	/* 1/64k is granular enough and can easily be handled w/ u32 */
+	HWEIGHT_WHOLE		= 1 << 16,
+
+	/*
+	 * As vtime is used to calculate the cost of each IO, it needs to
+	 * be fairly high precision.  For example, it should be able to
+	 * represent the cost of a single page worth of discard with
+	 * suffificient accuracy.  At the same time, it should be able to
+	 * represent reasonably long enough durations to be useful and
+	 * convenient during operation.
+	 *
+	 * 1s worth of vtime is 2^37.  This gives us both sub-nanosecond
+	 * granularity and days of wrap-around time even at extreme vrates.
+	 */
+	VTIME_PER_SEC_SHIFT	= 37,
+	VTIME_PER_SEC		= 1LLU << VTIME_PER_SEC_SHIFT,
+	VTIME_PER_USEC		= VTIME_PER_SEC / USEC_PER_SEC,
+
+	/* bound vrate adjustments within two orders of magnitude */
+	VRATE_MIN_PPM		= 10000,	/* 1% */
+	VRATE_MAX_PPM		= 100000000,	/* 10000% */
+
+	VRATE_MIN		= VTIME_PER_USEC * VRATE_MIN_PPM / MILLION,
+	VRATE_CLAMP_ADJ_PCT	= 4,
+
+	/* if IOs end up waiting for requests, issue less */
+	RQ_WAIT_BUSY_PCT	= 5,
+
+	/* unbusy hysterisis */
+	UNBUSY_THR_PCT		= 75,
+
+	/* don't let cmds which take a very long time pin lagging for too long */
+	MAX_LAGGING_PERIODS	= 10,
+
+	/*
+	 * If usage% * 1.25 + 2% is lower than hweight% by more than 3%,
+	 * donate the surplus.
+	 */
+	SURPLUS_SCALE_PCT	= 125,			/* * 125% */
+	SURPLUS_SCALE_ABS	= HWEIGHT_WHOLE / 50,	/* + 2% */
+	SURPLUS_MIN_ADJ_DELTA	= HWEIGHT_WHOLE / 33,	/* 3% */
+
+	/* switch iff the conditions are met for longer than this */
+	AUTOP_CYCLE_NSEC	= 10LLU * NSEC_PER_SEC,
+
+	/*
+	 * Count IO size in 4k pages.  The 12bit shift helps keeping
+	 * size-proportional components of cost calculation in closer
+	 * numbers of digits to per-IO cost components.
+	 */
+	IOC_PAGE_SHIFT		= 12,
+	IOC_PAGE_SIZE		= 1 << IOC_PAGE_SHIFT,
+	IOC_SECT_TO_PAGE_SHIFT	= IOC_PAGE_SHIFT - SECTOR_SHIFT,
+
+	/* if apart further than 16M, consider randio for linear model */
+	LCOEF_RANDIO_PAGES	= 4096,
+};
+
+enum ioc_running {
+	IOC_IDLE,
+	IOC_RUNNING,
+	IOC_STOP,
+};
+
+/* io.cost.qos controls including per-dev enable of the whole controller */
+enum {
+	QOS_ENABLE,
+	QOS_CTRL,
+	NR_QOS_CTRL_PARAMS,
+};
+
+/* io.cost.qos params */
+enum {
+	QOS_RPPM,
+	QOS_RLAT,
+	QOS_WPPM,
+	QOS_WLAT,
+	QOS_MIN,
+	QOS_MAX,
+	NR_QOS_PARAMS,
+};
+
+/* io.cost.model controls */
+enum {
+	COST_CTRL,
+	COST_MODEL,
+	NR_COST_CTRL_PARAMS,
+};
+
+/* builtin linear cost model coefficients */
+enum {
+	I_LCOEF_RBPS,
+	I_LCOEF_RSEQIOPS,
+	I_LCOEF_RRANDIOPS,
+	I_LCOEF_WBPS,
+	I_LCOEF_WSEQIOPS,
+	I_LCOEF_WRANDIOPS,
+	NR_I_LCOEFS,
+};
+
+enum {
+	LCOEF_RPAGE,
+	LCOEF_RSEQIO,
+	LCOEF_RRANDIO,
+	LCOEF_WPAGE,
+	LCOEF_WSEQIO,
+	LCOEF_WRANDIO,
+	NR_LCOEFS,
+};
+
+enum {
+	AUTOP_INVALID,
+	AUTOP_HDD,
+	AUTOP_SSD_QD1,
+	AUTOP_SSD_DFL,
+	AUTOP_SSD_FAST,
+};
+
+struct ioc_gq;
+
+struct ioc_params {
+	u32				qos[NR_QOS_PARAMS];
+	u64				i_lcoefs[NR_I_LCOEFS];
+	u64				lcoefs[NR_LCOEFS];
+	u32				too_fast_vrate_pct;
+	u32				too_slow_vrate_pct;
+};
+
+struct ioc_missed {
+	u32				nr_met;
+	u32				nr_missed;
+	u32				last_met;
+	u32				last_missed;
+};
+
+struct ioc_pcpu_stat {
+	struct ioc_missed		missed[2];
+
+	u64				rq_wait_ns;
+	u64				last_rq_wait_ns;
+};
+
+/* per device */
+struct ioc {
+	struct rq_qos			rqos;
+
+	bool				enabled;
+
+	struct ioc_params		params;
+	u32				period_us;
+	u32				margin_us;
+	u64				vrate_min;
+	u64				vrate_max;
+
+	spinlock_t			lock;
+	struct timer_list		timer;
+	struct list_head		active_iocgs;	/* active cgroups */
+	struct ioc_pcpu_stat __percpu	*pcpu_stat;
+
+	enum ioc_running		running;
+	atomic64_t			vtime_rate;
+
+	seqcount_t			period_seqcount;
+	u32				period_at;	/* wallclock starttime */
+	u64				period_at_vtime; /* vtime starttime */
+
+	atomic64_t			cur_period;	/* inc'd each period */
+	int				busy_level;	/* saturation history */
+
+	u64				inuse_margin_vtime;
+	bool				weights_updated;
+	atomic_t			hweight_gen;	/* for lazy hweights */
+
+	u64				autop_too_fast_at;
+	u64				autop_too_slow_at;
+	int				autop_idx;
+	bool				user_qos_params:1;
+	bool				user_cost_model:1;
+};
+
+/* per device-cgroup pair */
+struct ioc_gq {
+	struct blkg_policy_data		pd;
+	struct ioc			*ioc;
+
+	/*
+	 * A iocg can get its weight from two sources - an explicit
+	 * per-device-cgroup configuration or the default weight of the
+	 * cgroup.  `cfg_weight` is the explicit per-device-cgroup
+	 * configuration.  `weight` is the effective considering both
+	 * sources.
+	 *
+	 * When an idle cgroup becomes active its `active` goes from 0 to
+	 * `weight`.  `inuse` is the surplus adjusted active weight.
+	 * `active` and `inuse` are used to calculate `hweight_active` and
+	 * `hweight_inuse`.
+	 *
+	 * `last_inuse` remembers `inuse` while an iocg is idle to persist
+	 * surplus adjustments.
+	 */
+	u32				cfg_weight;
+	u32				weight;
+	u32				active;
+	u32				inuse;
+	u32				last_inuse;
+
+	sector_t			cursor;		/* to detect randio */
+
+	/*
+	 * `vtime` is this iocg's vtime cursor which progresses as IOs are
+	 * issued.  If lagging behind device vtime, the delta represents
+	 * the currently available IO budget.  If runnning ahead, the
+	 * overage.
+	 *
+	 * `vtime_done` is the same but progressed on completion rather
+	 * than issue.  The delta behind `vtime` represents the cost of
+	 * currently in-flight IOs.
+	 *
+	 * `last_vtime` is used to remember `vtime` at the end of the last
+	 * period to calculate utilization.
+	 */
+	atomic64_t			vtime;
+	atomic64_t			done_vtime;
+	u64				last_vtime;
+
+	/*
+	 * The period this iocg was last active in.  Used for deactivation
+	 * and invalidating `vtime`.
+	 */
+	atomic64_t			active_period;
+	struct list_head		active_list;
+
+	/* see __propagate_active_weight() and current_hweight() for details */
+	u64				child_active_sum;
+	u64				child_inuse_sum;
+	int				hweight_gen;
+	u32				hweight_active;
+	u32				hweight_inuse;
+	bool				has_surplus;
+
+	struct wait_queue_head		waitq;
+	struct hrtimer			waitq_timer;
+	struct hrtimer			delay_timer;
+
+	/* usage is recorded as fractions of HWEIGHT_WHOLE */
+	int				usage_idx;
+	u32				usages[NR_USAGE_SLOTS];
+
+	/* this iocg's depth in the hierarchy and ancestors including self */
+	int				level;
+	struct ioc_gq			*ancestors[];
+};
+
+/* per cgroup */
+struct ioc_cgrp {
+	struct blkcg_policy_data	cpd;
+	unsigned int			dfl_weight;
+};
+
+struct ioc_now {
+	u64				now_ns;
+	u32				now;
+	u64				vnow;
+	u64				vrate;
+};
+
+struct iocg_wait {
+	struct wait_queue_entry		wait;
+	struct bio			*bio;
+	u64				abs_cost;
+	bool				committed;
+};
+
+struct iocg_wake_ctx {
+	struct ioc_gq			*iocg;
+	u32				hw_inuse;
+	s64				vbudget;
+};
+
+static const struct ioc_params autop[] = {
+	[AUTOP_HDD] = {
+		.qos				= {
+			[QOS_RLAT]		=         50000, /* 50ms */
+			[QOS_WLAT]		=         50000,
+			[QOS_MIN]		= VRATE_MIN_PPM,
+			[QOS_MAX]		= VRATE_MAX_PPM,
+		},
+		.i_lcoefs			= {
+			[I_LCOEF_RBPS]		=     174019176,
+			[I_LCOEF_RSEQIOPS]	=         41708,
+			[I_LCOEF_RRANDIOPS]	=           370,
+			[I_LCOEF_WBPS]		=     178075866,
+			[I_LCOEF_WSEQIOPS]	=         42705,
+			[I_LCOEF_WRANDIOPS]	=           378,
+		},
+	},
+	[AUTOP_SSD_QD1] = {
+		.qos				= {
+			[QOS_RLAT]		=         25000, /* 25ms */
+			[QOS_WLAT]		=         25000,
+			[QOS_MIN]		= VRATE_MIN_PPM,
+			[QOS_MAX]		= VRATE_MAX_PPM,
+		},
+		.i_lcoefs			= {
+			[I_LCOEF_RBPS]		=     245855193,
+			[I_LCOEF_RSEQIOPS]	=         61575,
+			[I_LCOEF_RRANDIOPS]	=          6946,
+			[I_LCOEF_WBPS]		=     141365009,
+			[I_LCOEF_WSEQIOPS]	=         33716,
+			[I_LCOEF_WRANDIOPS]	=         26796,
+		},
+	},
+	[AUTOP_SSD_DFL] = {
+		.qos				= {
+			[QOS_RLAT]		=         25000, /* 25ms */
+			[QOS_WLAT]		=         25000,
+			[QOS_MIN]		= VRATE_MIN_PPM,
+			[QOS_MAX]		= VRATE_MAX_PPM,
+		},
+		.i_lcoefs			= {
+			[I_LCOEF_RBPS]		=     488636629,
+			[I_LCOEF_RSEQIOPS]	=          8932,
+			[I_LCOEF_RRANDIOPS]	=          8518,
+			[I_LCOEF_WBPS]		=     427891549,
+			[I_LCOEF_WSEQIOPS]	=         28755,
+			[I_LCOEF_WRANDIOPS]	=         21940,
+		},
+		.too_fast_vrate_pct		=           500,
+	},
+	[AUTOP_SSD_FAST] = {
+		.qos				= {
+			[QOS_RLAT]		=          5000, /* 5ms */
+			[QOS_WLAT]		=          5000,
+			[QOS_MIN]		= VRATE_MIN_PPM,
+			[QOS_MAX]		= VRATE_MAX_PPM,
+		},
+		.i_lcoefs			= {
+			[I_LCOEF_RBPS]		=    3102524156LLU,
+			[I_LCOEF_RSEQIOPS]	=        724816,
+			[I_LCOEF_RRANDIOPS]	=        778122,
+			[I_LCOEF_WBPS]		=    1742780862LLU,
+			[I_LCOEF_WSEQIOPS]	=        425702,
+			[I_LCOEF_WRANDIOPS]	=	 443193,
+		},
+		.too_slow_vrate_pct		=            10,
+	},
+};
+
+/*
+ * vrate adjust percentages indexed by ioc->busy_level.  We adjust up on
+ * vtime credit shortage and down on device saturation.
+ */
+static u32 vrate_adj_pct[] =
+	{ 0, 0, 0, 0,
+	  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+	  4, 4, 4, 4, 4, 4, 4, 4, 8, 8, 8, 8, 8, 8, 8, 8, 16 };
+
+static struct blkcg_policy blkcg_policy_iocost;
+
+/* accessors and helpers */
+static struct ioc *rqos_to_ioc(struct rq_qos *rqos)
+{
+	return container_of(rqos, struct ioc, rqos);
+}
+
+static struct ioc *q_to_ioc(struct request_queue *q)
+{
+	return rqos_to_ioc(rq_qos_id(q, RQ_QOS_COST));
+}
+
+static const char *q_name(struct request_queue *q)
+{
+	if (test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
+		return kobject_name(q->kobj.parent);
+	else
+		return "<unknown>";
+}
+
+static const char __maybe_unused *ioc_name(struct ioc *ioc)
+{
+	return q_name(ioc->rqos.q);
+}
+
+static struct ioc_gq *pd_to_iocg(struct blkg_policy_data *pd)
+{
+	return pd ? container_of(pd, struct ioc_gq, pd) : NULL;
+}
+
+static struct ioc_gq *blkg_to_iocg(struct blkcg_gq *blkg)
+{
+	return pd_to_iocg(blkg_to_pd(blkg, &blkcg_policy_iocost));
+}
+
+static struct blkcg_gq *iocg_to_blkg(struct ioc_gq *iocg)
+{
+	return pd_to_blkg(&iocg->pd);
+}
+
+static struct ioc_cgrp *blkcg_to_iocc(struct blkcg *blkcg)
+{
+	return container_of(blkcg_to_cpd(blkcg, &blkcg_policy_iocost),
+			    struct ioc_cgrp, cpd);
+}
+
+/*
+ * Scale @abs_cost to the inverse of @hw_inuse.  The lower the hierarchical
+ * weight, the more expensive each IO.
+ */
+static u64 abs_cost_to_cost(u64 abs_cost, u32 hw_inuse)
+{
+	return DIV64_U64_ROUND_UP(abs_cost * HWEIGHT_WHOLE, hw_inuse);
+}
+
+static void iocg_commit_bio(struct ioc_gq *iocg, struct bio *bio, u64 cost)
+{
+	bio->bi_iocost_cost = cost;
+	atomic64_add(cost, &iocg->vtime);
+}
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/iocost.h>
+
+/* latency Qos params changed, update period_us and all the dependent params */
+static void ioc_refresh_period_us(struct ioc *ioc)
+{
+	u32 ppm, lat, multi, period_us;
+
+	lockdep_assert_held(&ioc->lock);
+
+	/* pick the higher latency target */
+	if (ioc->params.qos[QOS_RLAT] >= ioc->params.qos[QOS_WLAT]) {
+		ppm = ioc->params.qos[QOS_RPPM];
+		lat = ioc->params.qos[QOS_RLAT];
+	} else {
+		ppm = ioc->params.qos[QOS_WPPM];
+		lat = ioc->params.qos[QOS_WLAT];
+	}
+
+	/*
+	 * We want the period to be long enough to contain a healthy number
+	 * of IOs while short enough for granular control.  Define it as a
+	 * multiple of the latency target.  Ideally, the multiplier should
+	 * be scaled according to the percentile so that it would nominally
+	 * contain a certain number of requests.  Let's be simpler and
+	 * scale it linearly so that it's 2x >= pct(90) and 10x at pct(50).
+	 */
+	if (ppm)
+		multi = max_t(u32, (MILLION - ppm) / 50000, 2);
+	else
+		multi = 2;
+	period_us = multi * lat;
+	period_us = clamp_t(u32, period_us, MIN_PERIOD, MAX_PERIOD);
+
+	/* calculate dependent params */
+	ioc->period_us = period_us;
+	ioc->margin_us = period_us * MARGIN_PCT / 100;
+	ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP(
+			period_us * VTIME_PER_USEC * INUSE_MARGIN_PCT, 100);
+}
+
+static int ioc_autop_idx(struct ioc *ioc)
+{
+	int idx = ioc->autop_idx;
+	const struct ioc_params *p = &autop[idx];
+	u32 vrate_pct;
+	u64 now_ns;
+
+	/* rotational? */
+	if (!blk_queue_nonrot(ioc->rqos.q))
+		return AUTOP_HDD;
+
+	/* handle SATA SSDs w/ broken NCQ */
+	if (blk_queue_depth(ioc->rqos.q) == 1)
+		return AUTOP_SSD_QD1;
+
+	/* use one of the normal ssd sets */
+	if (idx < AUTOP_SSD_DFL)
+		return AUTOP_SSD_DFL;
+
+	/* if user is overriding anything, maintain what was there */
+	if (ioc->user_qos_params || ioc->user_cost_model)
+		return idx;
+
+	/* step up/down based on the vrate */
+	vrate_pct = div64_u64(atomic64_read(&ioc->vtime_rate) * 100,
+			      VTIME_PER_USEC);
+	now_ns = ktime_get_ns();
+
+	if (p->too_fast_vrate_pct && p->too_fast_vrate_pct <= vrate_pct) {
+		if (!ioc->autop_too_fast_at)
+			ioc->autop_too_fast_at = now_ns;
+		if (now_ns - ioc->autop_too_fast_at >= AUTOP_CYCLE_NSEC)
+			return idx + 1;
+	} else {
+		ioc->autop_too_fast_at = 0;
+	}
+
+	if (p->too_slow_vrate_pct && p->too_slow_vrate_pct >= vrate_pct) {
+		if (!ioc->autop_too_slow_at)
+			ioc->autop_too_slow_at = now_ns;
+		if (now_ns - ioc->autop_too_slow_at >= AUTOP_CYCLE_NSEC)
+			return idx - 1;
+	} else {
+		ioc->autop_too_slow_at = 0;
+	}
+
+	return idx;
+}
+
+/*
+ * Take the followings as input
+ *
+ *  @bps	maximum sequential throughput
+ *  @seqiops	maximum sequential 4k iops
+ *  @randiops	maximum random 4k iops
+ *
+ * and calculate the linear model cost coefficients.
+ *
+ *  *@page	per-page cost		1s / (@bps / 4096)
+ *  *@seqio	base cost of a seq IO	max((1s / @seqiops) - *@page, 0)
+ *  @randiops	base cost of a rand IO	max((1s / @randiops) - *@page, 0)
+ */
+static void calc_lcoefs(u64 bps, u64 seqiops, u64 randiops,
+			u64 *page, u64 *seqio, u64 *randio)
+{
+	u64 v;
+
+	*page = *seqio = *randio = 0;
+
+	if (bps)
+		*page = DIV64_U64_ROUND_UP(VTIME_PER_SEC,
+					   DIV_ROUND_UP_ULL(bps, IOC_PAGE_SIZE));
+
+	if (seqiops) {
+		v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, seqiops);
+		if (v > *page)
+			*seqio = v - *page;
+	}
+
+	if (randiops) {
+		v = DIV64_U64_ROUND_UP(VTIME_PER_SEC, randiops);
+		if (v > *page)
+			*randio = v - *page;
+	}
+}
+
+static void ioc_refresh_lcoefs(struct ioc *ioc)
+{
+	u64 *u = ioc->params.i_lcoefs;
+	u64 *c = ioc->params.lcoefs;
+
+	calc_lcoefs(u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS],
+		    &c[LCOEF_RPAGE], &c[LCOEF_RSEQIO], &c[LCOEF_RRANDIO]);
+	calc_lcoefs(u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS],
+		    &c[LCOEF_WPAGE], &c[LCOEF_WSEQIO], &c[LCOEF_WRANDIO]);
+}
+
+static bool ioc_refresh_params(struct ioc *ioc, bool force)
+{
+	const struct ioc_params *p;
+	int idx;
+
+	lockdep_assert_held(&ioc->lock);
+
+	idx = ioc_autop_idx(ioc);
+	p = &autop[idx];
+
+	if (idx == ioc->autop_idx && !force)
+		return false;
+
+	if (idx != ioc->autop_idx)
+		atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC);
+
+	ioc->autop_idx = idx;
+	ioc->autop_too_fast_at = 0;
+	ioc->autop_too_slow_at = 0;
+
+	if (!ioc->user_qos_params)
+		memcpy(ioc->params.qos, p->qos, sizeof(p->qos));
+	if (!ioc->user_cost_model)
+		memcpy(ioc->params.i_lcoefs, p->i_lcoefs, sizeof(p->i_lcoefs));
+
+	ioc_refresh_period_us(ioc);
+	ioc_refresh_lcoefs(ioc);
+
+	ioc->vrate_min = DIV64_U64_ROUND_UP((u64)ioc->params.qos[QOS_MIN] *
+					    VTIME_PER_USEC, MILLION);
+	ioc->vrate_max = div64_u64((u64)ioc->params.qos[QOS_MAX] *
+				   VTIME_PER_USEC, MILLION);
+
+	return true;
+}
+
+/* take a snapshot of the current [v]time and vrate */
+static void ioc_now(struct ioc *ioc, struct ioc_now *now)
+{
+	unsigned seq;
+
+	now->now_ns = ktime_get();
+	now->now = ktime_to_us(now->now_ns);
+	now->vrate = atomic64_read(&ioc->vtime_rate);
+
+	/*
+	 * The current vtime is
+	 *
+	 *   vtime at period start + (wallclock time since the start) * vrate
+	 *
+	 * As a consistent snapshot of `period_at_vtime` and `period_at` is
+	 * needed, they're seqcount protected.
+	 */
+	do {
+		seq = read_seqcount_begin(&ioc->period_seqcount);
+		now->vnow = ioc->period_at_vtime +
+			(now->now - ioc->period_at) * now->vrate;
+	} while (read_seqcount_retry(&ioc->period_seqcount, seq));
+}
+
+static void ioc_start_period(struct ioc *ioc, struct ioc_now *now)
+{
+	lockdep_assert_held(&ioc->lock);
+	WARN_ON_ONCE(ioc->running != IOC_RUNNING);
+
+	write_seqcount_begin(&ioc->period_seqcount);
+	ioc->period_at = now->now;
+	ioc->period_at_vtime = now->vnow;
+	write_seqcount_end(&ioc->period_seqcount);
+
+	ioc->timer.expires = jiffies + usecs_to_jiffies(ioc->period_us);
+	add_timer(&ioc->timer);
+}
+
+/*
+ * Update @iocg's `active` and `inuse` to @active and @inuse, update level
+ * weight sums and propagate upwards accordingly.
+ */
+static void __propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse)
+{
+	struct ioc *ioc = iocg->ioc;
+	int lvl;
+
+	lockdep_assert_held(&ioc->lock);
+
+	inuse = min(active, inuse);
+
+	for (lvl = iocg->level - 1; lvl >= 0; lvl--) {
+		struct ioc_gq *parent = iocg->ancestors[lvl];
+		struct ioc_gq *child = iocg->ancestors[lvl + 1];
+		u32 parent_active = 0, parent_inuse = 0;
+
+		/* update the level sums */
+		parent->child_active_sum += (s32)(active - child->active);
+		parent->child_inuse_sum += (s32)(inuse - child->inuse);
+		/* apply the udpates */
+		child->active = active;
+		child->inuse = inuse;
+
+		/*
+		 * The delta between inuse and active sums indicates that
+		 * that much of weight is being given away.  Parent's inuse
+		 * and active should reflect the ratio.
+		 */
+		if (parent->child_active_sum) {
+			parent_active = parent->weight;
+			parent_inuse = DIV64_U64_ROUND_UP(
+				parent_active * parent->child_inuse_sum,
+				parent->child_active_sum);
+		}
+
+		/* do we need to keep walking up? */
+		if (parent_active == parent->active &&
+		    parent_inuse == parent->inuse)
+			break;
+
+		active = parent_active;
+		inuse = parent_inuse;
+	}
+
+	ioc->weights_updated = true;
+}
+
+static void commit_active_weights(struct ioc *ioc)
+{
+	lockdep_assert_held(&ioc->lock);
+
+	if (ioc->weights_updated) {
+		/* paired with rmb in current_hweight(), see there */
+		smp_wmb();
+		atomic_inc(&ioc->hweight_gen);
+		ioc->weights_updated = false;
+	}
+}
+
+static void propagate_active_weight(struct ioc_gq *iocg, u32 active, u32 inuse)
+{
+	__propagate_active_weight(iocg, active, inuse);
+	commit_active_weights(iocg->ioc);
+}
+
+static void current_hweight(struct ioc_gq *iocg, u32 *hw_activep, u32 *hw_inusep)
+{
+	struct ioc *ioc = iocg->ioc;
+	int lvl;
+	u32 hwa, hwi;
+	int ioc_gen;
+
+	/* hot path - if uptodate, use cached */
+	ioc_gen = atomic_read(&ioc->hweight_gen);
+	if (ioc_gen == iocg->hweight_gen)
+		goto out;
+
+	/*
+	 * Paired with wmb in commit_active_weights().  If we saw the
+	 * updated hweight_gen, all the weight updates from
+	 * __propagate_active_weight() are visible too.
+	 *
+	 * We can race with weight updates during calculation and get it
+	 * wrong.  However, hweight_gen would have changed and a future
+	 * reader will recalculate and we're guaranteed to discard the
+	 * wrong result soon.
+	 */
+	smp_rmb();
+
+	hwa = hwi = HWEIGHT_WHOLE;
+	for (lvl = 0; lvl <= iocg->level - 1; lvl++) {
+		struct ioc_gq *parent = iocg->ancestors[lvl];
+		struct ioc_gq *child = iocg->ancestors[lvl + 1];
+		u32 active_sum = READ_ONCE(parent->child_active_sum);
+		u32 inuse_sum = READ_ONCE(parent->child_inuse_sum);
+		u32 active = READ_ONCE(child->active);
+		u32 inuse = READ_ONCE(child->inuse);
+
+		if (!active_sum)
+			continue;
+
+		active_sum = max(active, active_sum);
+		hwa = hwa * active / active_sum;	/* max 16bits * 10000 */
+
+		inuse_sum = max(inuse, inuse_sum);
+		hwi = hwi * inuse / inuse_sum;		/* max 16bits * 10000 */
+	}
+
+	iocg->hweight_active = max_t(u32, hwa, 1);
+	iocg->hweight_inuse = max_t(u32, hwi, 1);
+	iocg->hweight_gen = ioc_gen;
+out:
+	if (hw_activep)
+		*hw_activep = iocg->hweight_active;
+	if (hw_inusep)
+		*hw_inusep = iocg->hweight_inuse;
+}
+
+static void weight_updated(struct ioc_gq *iocg)
+{
+	struct ioc *ioc = iocg->ioc;
+	struct blkcg_gq *blkg = iocg_to_blkg(iocg);
+	struct ioc_cgrp *iocc = blkcg_to_iocc(blkg->blkcg);
+	u32 weight;
+
+	lockdep_assert_held(&ioc->lock);
+
+	weight = iocg->cfg_weight ?: iocc->dfl_weight;
+	if (weight != iocg->weight && iocg->active)
+		propagate_active_weight(iocg, weight,
+			DIV64_U64_ROUND_UP(iocg->inuse * weight, iocg->weight));
+	iocg->weight = weight;
+}
+
+static bool iocg_activate(struct ioc_gq *iocg, struct ioc_now *now)
+{
+	struct ioc *ioc = iocg->ioc;
+	u64 last_period, cur_period, max_period_delta;
+	u64 vtime, vmargin, vmin;
+	int i;
+
+	/*
+	 * If seem to be already active, just update the stamp to tell the
+	 * timer that we're still active.  We don't mind occassional races.
+	 */
+	if (!list_empty(&iocg->active_list)) {
+		ioc_now(ioc, now);
+		cur_period = atomic64_read(&ioc->cur_period);
+		if (atomic64_read(&iocg->active_period) != cur_period)
+			atomic64_set(&iocg->active_period, cur_period);
+		return true;
+	}
+
+	/* racy check on internal node IOs, treat as root level IOs */
+	if (iocg->child_active_sum)
+		return false;
+
+	spin_lock_irq(&ioc->lock);
+
+	ioc_now(ioc, now);
+
+	/* update period */
+	cur_period = atomic64_read(&ioc->cur_period);
+	last_period = atomic64_read(&iocg->active_period);
+	atomic64_set(&iocg->active_period, cur_period);
+
+	/* already activated or breaking leaf-only constraint? */
+	for (i = iocg->level; i > 0; i--)
+		if (!list_empty(&iocg->active_list))
+			goto fail_unlock;
+	if (iocg->child_active_sum)
+		goto fail_unlock;
+
+	/*
+	 * vtime may wrap when vrate is raised substantially due to
+	 * underestimated IO costs.  Look at the period and ignore its
+	 * vtime if the iocg has been idle for too long.  Also, cap the
+	 * budget it can start with to the margin.
+	 */
+	max_period_delta = DIV64_U64_ROUND_UP(VTIME_VALID_DUR, ioc->period_us);
+	vtime = atomic64_read(&iocg->vtime);
+	vmargin = ioc->margin_us * now->vrate;
+	vmin = now->vnow - vmargin;
+
+	if (last_period + max_period_delta < cur_period ||
+	    time_before64(vtime, vmin)) {
+		atomic64_add(vmin - vtime, &iocg->vtime);
+		atomic64_add(vmin - vtime, &iocg->done_vtime);
+		vtime = vmin;
+	}
+
+	/*
+	 * Activate, propagate weight and start period timer if not
+	 * running.  Reset hweight_gen to avoid accidental match from
+	 * wrapping.
+	 */
+	iocg->hweight_gen = atomic_read(&ioc->hweight_gen) - 1;
+	list_add(&iocg->active_list, &ioc->active_iocgs);
+	propagate_active_weight(iocg, iocg->weight,
+				iocg->last_inuse ?: iocg->weight);
+
+	TRACE_IOCG_PATH(iocg_activate, iocg, now,
+			last_period, cur_period, vtime);
+
+	iocg->last_vtime = vtime;
+
+	if (ioc->running == IOC_IDLE) {
+		ioc->running = IOC_RUNNING;
+		ioc_start_period(ioc, now);
+	}
+
+	spin_unlock_irq(&ioc->lock);
+	return true;
+
+fail_unlock:
+	spin_unlock_irq(&ioc->lock);
+	return false;
+}
+
+static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode,
+			int flags, void *key)
+{
+	struct iocg_wait *wait = container_of(wq_entry, struct iocg_wait, wait);
+	struct iocg_wake_ctx *ctx = (struct iocg_wake_ctx *)key;
+	u64 cost = abs_cost_to_cost(wait->abs_cost, ctx->hw_inuse);
+
+	ctx->vbudget -= cost;
+
+	if (ctx->vbudget < 0)
+		return -1;
+
+	iocg_commit_bio(ctx->iocg, wait->bio, cost);
+
+	/*
+	 * autoremove_wake_function() removes the wait entry only when it
+	 * actually changed the task state.  We want the wait always
+	 * removed.  Remove explicitly and use default_wake_function().
+	 */
+	list_del_init(&wq_entry->entry);
+	wait->committed = true;
+
+	default_wake_function(wq_entry, mode, flags, key);
+	return 0;
+}
+
+static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now)
+{
+	struct ioc *ioc = iocg->ioc;
+	struct iocg_wake_ctx ctx = { .iocg = iocg };
+	u64 margin_ns = (u64)(ioc->period_us *
+			      WAITQ_TIMER_MARGIN_PCT / 100) * NSEC_PER_USEC;
+	u64 vshortage, expires, oexpires;
+
+	lockdep_assert_held(&iocg->waitq.lock);
+
+	/*
+	 * Wake up the ones which are due and see how much vtime we'll need
+	 * for the next one.
+	 */
+	current_hweight(iocg, NULL, &ctx.hw_inuse);
+	ctx.vbudget = now->vnow - atomic64_read(&iocg->vtime);
+	__wake_up_locked_key(&iocg->waitq, TASK_NORMAL, &ctx);
+	if (!waitqueue_active(&iocg->waitq))
+		return;
+	if (WARN_ON_ONCE(ctx.vbudget >= 0))
+		return;
+
+	/* determine next wakeup, add a quarter margin to guarantee chunking */
+	vshortage = -ctx.vbudget;
+	expires = now->now_ns +
+		DIV64_U64_ROUND_UP(vshortage, now->vrate) * NSEC_PER_USEC;
+	expires += margin_ns / 4;
+
+	/* if already active and close enough, don't bother */
+	oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->waitq_timer));
+	if (hrtimer_is_queued(&iocg->waitq_timer) &&
+	    abs(oexpires - expires) <= margin_ns / 4)
+		return;
+
+	hrtimer_start_range_ns(&iocg->waitq_timer, ns_to_ktime(expires),
+			       margin_ns / 4, HRTIMER_MODE_ABS);
+}
+
+static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer)
+{
+	struct ioc_gq *iocg = container_of(timer, struct ioc_gq, waitq_timer);
+	struct ioc_now now;
+	unsigned long flags;
+
+	ioc_now(iocg->ioc, &now);
+
+	spin_lock_irqsave(&iocg->waitq.lock, flags);
+	iocg_kick_waitq(iocg, &now);
+	spin_unlock_irqrestore(&iocg->waitq.lock, flags);
+
+	return HRTIMER_NORESTART;
+}
+
+static void iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
+{
+	struct ioc *ioc = iocg->ioc;
+	struct blkcg_gq *blkg = iocg_to_blkg(iocg);
+	u64 vtime = atomic64_read(&iocg->vtime);
+	u64 vmargin = ioc->margin_us * now->vrate;
+	u64 margin_ns = ioc->margin_us * NSEC_PER_USEC;
+	u64 expires, oexpires;
+
+	/* clear or maintain depending on the overage */
+	if (time_before_eq64(vtime, now->vnow)) {
+		blkcg_clear_delay(blkg);
+		return;
+	}
+	if (!atomic_read(&blkg->use_delay) &&
+	    time_before_eq64(vtime, now->vnow + vmargin))
+		return;
+
+	/* use delay */
+	if (cost) {
+		u64 cost_ns = DIV64_U64_ROUND_UP(cost * NSEC_PER_USEC,
+						 now->vrate);
+		blkcg_add_delay(blkg, now->now_ns, cost_ns);
+	}
+	blkcg_use_delay(blkg);
+
+	expires = now->now_ns + DIV64_U64_ROUND_UP(vtime - now->vnow,
+						   now->vrate) * NSEC_PER_USEC;
+
+	/* if already active and close enough, don't bother */
+	oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer));
+	if (hrtimer_is_queued(&iocg->delay_timer) &&
+	    abs(oexpires - expires) <= margin_ns / 4)
+		return;
+
+	hrtimer_start_range_ns(&iocg->delay_timer, ns_to_ktime(expires),
+			       margin_ns / 4, HRTIMER_MODE_ABS);
+}
+
+static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer)
+{
+	struct ioc_gq *iocg = container_of(timer, struct ioc_gq, delay_timer);
+	struct ioc_now now;
+
+	ioc_now(iocg->ioc, &now);
+	iocg_kick_delay(iocg, &now, 0);
+
+	return HRTIMER_NORESTART;
+}
+
+static void ioc_lat_stat(struct ioc *ioc, u32 *missed_ppm_ar, u32 *rq_wait_pct_p)
+{
+	u32 nr_met[2] = { };
+	u32 nr_missed[2] = { };
+	u64 rq_wait_ns = 0;
+	int cpu, rw;
+
+	for_each_online_cpu(cpu) {
+		struct ioc_pcpu_stat *stat = per_cpu_ptr(ioc->pcpu_stat, cpu);
+		u64 this_rq_wait_ns;
+
+		for (rw = READ; rw <= WRITE; rw++) {
+			u32 this_met = READ_ONCE(stat->missed[rw].nr_met);
+			u32 this_missed = READ_ONCE(stat->missed[rw].nr_missed);
+
+			nr_met[rw] += this_met - stat->missed[rw].last_met;
+			nr_missed[rw] += this_missed - stat->missed[rw].last_missed;
+			stat->missed[rw].last_met = this_met;
+			stat->missed[rw].last_missed = this_missed;
+		}
+
+		this_rq_wait_ns = READ_ONCE(stat->rq_wait_ns);
+		rq_wait_ns += this_rq_wait_ns - stat->last_rq_wait_ns;
+		stat->last_rq_wait_ns = this_rq_wait_ns;
+	}
+
+	for (rw = READ; rw <= WRITE; rw++) {
+		if (nr_met[rw] + nr_missed[rw])
+			missed_ppm_ar[rw] =
+				DIV64_U64_ROUND_UP((u64)nr_missed[rw] * MILLION,
+						   nr_met[rw] + nr_missed[rw]);
+		else
+			missed_ppm_ar[rw] = 0;
+	}
+
+	*rq_wait_pct_p = div64_u64(rq_wait_ns * 100,
+				   ioc->period_us * NSEC_PER_USEC);
+}
+
+/* was iocg idle this period? */
+static bool iocg_is_idle(struct ioc_gq *iocg)
+{
+	struct ioc *ioc = iocg->ioc;
+
+	/* did something get issued this period? */
+	if (atomic64_read(&iocg->active_period) ==
+	    atomic64_read(&ioc->cur_period))
+		return false;
+
+	/* is something in flight? */
+	if (atomic64_read(&iocg->done_vtime) < atomic64_read(&iocg->vtime))
+		return false;
+
+	return true;
+}
+
+/* returns usage with margin added if surplus is large enough */
+static u32 surplus_adjusted_hweight_inuse(u32 usage, u32 hw_inuse)
+{
+	/* add margin */
+	usage = DIV_ROUND_UP(usage * SURPLUS_SCALE_PCT, 100);
+	usage += SURPLUS_SCALE_ABS;
+
+	/* don't bother if the surplus is too small */
+	if (usage + SURPLUS_MIN_ADJ_DELTA > hw_inuse)
+		return 0;
+
+	return usage;
+}
+
+static void ioc_timer_fn(struct timer_list *timer)
+{
+	struct ioc *ioc = container_of(timer, struct ioc, timer);
+	struct ioc_gq *iocg, *tiocg;
+	struct ioc_now now;
+	int nr_surpluses = 0, nr_shortages = 0, nr_lagging = 0;
+	u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM];
+	u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];
+	u32 missed_ppm[2], rq_wait_pct;
+	u64 period_vtime;
+	int i;
+
+	/* how were the latencies during the period? */
+	ioc_lat_stat(ioc, missed_ppm, &rq_wait_pct);
+
+	/* take care of active iocgs */
+	spin_lock_irq(&ioc->lock);
+
+	ioc_now(ioc, &now);
+
+	period_vtime = now.vnow - ioc->period_at_vtime;
+	if (WARN_ON_ONCE(!period_vtime)) {
+		spin_unlock_irq(&ioc->lock);
+		return;
+	}
+
+	/*
+	 * Waiters determine the sleep durations based on the vrate they
+	 * saw at the time of sleep.  If vrate has increased, some waiters
+	 * could be sleeping for too long.  Wake up tardy waiters which
+	 * should have woken up in the last period and expire idle iocgs.
+	 */
+	list_for_each_entry_safe(iocg, tiocg, &ioc->active_iocgs, active_list) {
+		if (!waitqueue_active(&iocg->waitq) && !iocg_is_idle(iocg))
+			continue;
+
+		spin_lock(&iocg->waitq.lock);
+
+		if (waitqueue_active(&iocg->waitq)) {
+			/* might be oversleeping vtime / hweight changes, kick */
+			iocg_kick_waitq(iocg, &now);
+			iocg_kick_delay(iocg, &now, 0);
+		} else if (iocg_is_idle(iocg)) {
+			/* no waiter and idle, deactivate */
+			iocg->last_inuse = iocg->inuse;
+			__propagate_active_weight(iocg, 0, 0);
+			list_del_init(&iocg->active_list);
+		}
+
+		spin_unlock(&iocg->waitq.lock);
+	}
+	commit_active_weights(ioc);
+
+	/* calc usages and see whether some weights need to be moved around */
+	list_for_each_entry(iocg, &ioc->active_iocgs, active_list) {
+		u64 vdone, vtime, vusage, vmargin, vmin;
+		u32 hw_active, hw_inuse, usage;
+
+		/*
+		 * Collect unused and wind vtime closer to vnow to prevent
+		 * iocgs from accumulating a large amount of budget.
+		 */
+		vdone = atomic64_read(&iocg->done_vtime);
+		vtime = atomic64_read(&iocg->vtime);
+		current_hweight(iocg, &hw_active, &hw_inuse);
+
+		/*
+		 * Latency QoS detection doesn't account for IOs which are
+		 * in-flight for longer than a period.  Detect them by
+		 * comparing vdone against period start.  If lagging behind
+		 * IOs from past periods, don't increase vrate.
+		 */
+		if (!atomic_read(&iocg_to_blkg(iocg)->use_delay) &&
+		    time_after64(vtime, vdone) &&
+		    time_after64(vtime, now.vnow -
+				 MAX_LAGGING_PERIODS * period_vtime) &&
+		    time_before64(vdone, now.vnow - period_vtime))
+			nr_lagging++;
+
+		if (waitqueue_active(&iocg->waitq))
+			vusage = now.vnow - iocg->last_vtime;
+		else if (time_before64(iocg->last_vtime, vtime))
+			vusage = vtime - iocg->last_vtime;
+		else
+			vusage = 0;
+
+		iocg->last_vtime += vusage;
+		/*
+		 * Factor in in-flight vtime into vusage to avoid
+		 * high-latency completions appearing as idle.  This should
+		 * be done after the above ->last_time adjustment.
+		 */
+		vusage = max(vusage, vtime - vdone);
+
+		/* calculate hweight based usage ratio and record */
+		if (vusage) {
+			usage = DIV64_U64_ROUND_UP(vusage * hw_inuse,
+						   period_vtime);
+			iocg->usage_idx = (iocg->usage_idx + 1) % NR_USAGE_SLOTS;
+			iocg->usages[iocg->usage_idx] = usage;
+		} else {
+			usage = 0;
+		}
+
+		/* see whether there's surplus vtime */
+		vmargin = ioc->margin_us * now.vrate;
+		vmin = now.vnow - vmargin;
+
+		iocg->has_surplus = false;
+
+		if (!waitqueue_active(&iocg->waitq) &&
+		    time_before64(vtime, vmin)) {
+			u64 delta = vmin - vtime;
+
+			/* throw away surplus vtime */
+			atomic64_add(delta, &iocg->vtime);
+			atomic64_add(delta, &iocg->done_vtime);
+			iocg->last_vtime += delta;
+			/* if usage is sufficiently low, maybe it can donate */
+			if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) {
+				iocg->has_surplus = true;
+				nr_surpluses++;
+			}
+		} else if (hw_inuse < hw_active) {
+			u32 new_hwi, new_inuse;
+
+			/* was donating but might need to take back some */
+			if (waitqueue_active(&iocg->waitq)) {
+				new_hwi = hw_active;
+			} else {
+				new_hwi = max(hw_inuse,
+					      usage * SURPLUS_SCALE_PCT / 100 +
+					      SURPLUS_SCALE_ABS);
+			}
+
+			new_inuse = div64_u64((u64)iocg->inuse * new_hwi,
+					      hw_inuse);
+			new_inuse = clamp_t(u32, new_inuse, 1, iocg->active);
+
+			if (new_inuse > iocg->inuse) {
+				TRACE_IOCG_PATH(inuse_takeback, iocg, &now,
+						iocg->inuse, new_inuse,
+						hw_inuse, new_hwi);
+				__propagate_active_weight(iocg, iocg->weight,
+							  new_inuse);
+			}
+		} else {
+			/* genuninely out of vtime */
+			nr_shortages++;
+		}
+	}
+
+	if (!nr_shortages || !nr_surpluses)
+		goto skip_surplus_transfers;
+
+	/* there are both shortages and surpluses, transfer surpluses */
+	list_for_each_entry(iocg, &ioc->active_iocgs, active_list) {
+		u32 usage, hw_active, hw_inuse, new_hwi, new_inuse;
+		int nr_valid = 0;
+
+		if (!iocg->has_surplus)
+			continue;
+
+		/* base the decision on max historical usage */
+		for (i = 0, usage = 0; i < NR_USAGE_SLOTS; i++) {
+			if (iocg->usages[i]) {
+				usage = max(usage, iocg->usages[i]);
+				nr_valid++;
+			}
+		}
+		if (nr_valid < MIN_VALID_USAGES)
+			continue;
+
+		current_hweight(iocg, &hw_active, &hw_inuse);
+		new_hwi = surplus_adjusted_hweight_inuse(usage, hw_inuse);
+		if (!new_hwi)
+			continue;
+
+		new_inuse = DIV64_U64_ROUND_UP((u64)iocg->inuse * new_hwi,
+					       hw_inuse);
+		if (new_inuse < iocg->inuse) {
+			TRACE_IOCG_PATH(inuse_giveaway, iocg, &now,
+					iocg->inuse, new_inuse,
+					hw_inuse, new_hwi);
+			__propagate_active_weight(iocg, iocg->weight, new_inuse);
+		}
+	}
+skip_surplus_transfers:
+	commit_active_weights(ioc);
+
+	/*
+	 * If q is getting clogged or we're missing too much, we're issuing
+	 * too much IO and should lower vtime rate.  If we're not missing
+	 * and experiencing shortages but not surpluses, we're too stingy
+	 * and should increase vtime rate.
+	 */
+	if (rq_wait_pct > RQ_WAIT_BUSY_PCT ||
+	    missed_ppm[READ] > ppm_rthr ||
+	    missed_ppm[WRITE] > ppm_wthr) {
+		ioc->busy_level = max(ioc->busy_level, 0);
+		ioc->busy_level++;
+	} else if (nr_lagging) {
+		ioc->busy_level = max(ioc->busy_level, 0);
+	} else if (nr_shortages && !nr_surpluses &&
+		   rq_wait_pct <= RQ_WAIT_BUSY_PCT * UNBUSY_THR_PCT / 100 &&
+		   missed_ppm[READ] <= ppm_rthr * UNBUSY_THR_PCT / 100 &&
+		   missed_ppm[WRITE] <= ppm_wthr * UNBUSY_THR_PCT / 100) {
+		ioc->busy_level = min(ioc->busy_level, 0);
+		ioc->busy_level--;
+	} else {
+		ioc->busy_level = 0;
+	}
+
+	ioc->busy_level = clamp(ioc->busy_level, -1000, 1000);
+
+	if (ioc->busy_level) {
+		u64 vrate = atomic64_read(&ioc->vtime_rate);
+		u64 vrate_min = ioc->vrate_min, vrate_max = ioc->vrate_max;
+
+		/* rq_wait signal is always reliable, ignore user vrate_min */
+		if (rq_wait_pct > RQ_WAIT_BUSY_PCT)
+			vrate_min = VRATE_MIN;
+
+		/*
+		 * If vrate is out of bounds, apply clamp gradually as the
+		 * bounds can change abruptly.  Otherwise, apply busy_level
+		 * based adjustment.
+		 */
+		if (vrate < vrate_min) {
+			vrate = div64_u64(vrate * (100 + VRATE_CLAMP_ADJ_PCT),
+					  100);
+			vrate = min(vrate, vrate_min);
+		} else if (vrate > vrate_max) {
+			vrate = div64_u64(vrate * (100 - VRATE_CLAMP_ADJ_PCT),
+					  100);
+			vrate = max(vrate, vrate_max);
+		} else {
+			int idx = min_t(int, abs(ioc->busy_level),
+					ARRAY_SIZE(vrate_adj_pct) - 1);
+			u32 adj_pct = vrate_adj_pct[idx];
+
+			if (ioc->busy_level > 0)
+				adj_pct = 100 - adj_pct;
+			else
+				adj_pct = 100 + adj_pct;
+
+			vrate = clamp(DIV64_U64_ROUND_UP(vrate * adj_pct, 100),
+				      vrate_min, vrate_max);
+		}
+
+		trace_iocost_ioc_vrate_adj(ioc, vrate, &missed_ppm, rq_wait_pct,
+					   nr_lagging, nr_shortages,
+					   nr_surpluses);
+
+		atomic64_set(&ioc->vtime_rate, vrate);
+		ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP(
+			ioc->period_us * vrate * INUSE_MARGIN_PCT, 100);
+	}
+
+	ioc_refresh_params(ioc, false);
+
+	/*
+	 * This period is done.  Move onto the next one.  If nothing's
+	 * going on with the device, stop the timer.
+	 */
+	atomic64_inc(&ioc->cur_period);
+
+	if (ioc->running != IOC_STOP) {
+		if (!list_empty(&ioc->active_iocgs)) {
+			ioc_start_period(ioc, &now);
+		} else {
+			ioc->busy_level = 0;
+			ioc->running = IOC_IDLE;
+		}
+	}
+
+	spin_unlock_irq(&ioc->lock);
+}
+
+static void calc_vtime_cost_builtin(struct bio *bio, struct ioc_gq *iocg,
+				    bool is_merge, u64 *costp)
+{
+	struct ioc *ioc = iocg->ioc;
+	u64 coef_seqio, coef_randio, coef_page;
+	u64 pages = max_t(u64, bio_sectors(bio) >> IOC_SECT_TO_PAGE_SHIFT, 1);
+	u64 seek_pages = 0;
+	u64 cost = 0;
+
+	switch (bio_op(bio)) {
+	case REQ_OP_READ:
+		coef_seqio	= ioc->params.lcoefs[LCOEF_RSEQIO];
+		coef_randio	= ioc->params.lcoefs[LCOEF_RRANDIO];
+		coef_page	= ioc->params.lcoefs[LCOEF_RPAGE];
+		break;
+	case REQ_OP_WRITE:
+		coef_seqio	= ioc->params.lcoefs[LCOEF_WSEQIO];
+		coef_randio	= ioc->params.lcoefs[LCOEF_WRANDIO];
+		coef_page	= ioc->params.lcoefs[LCOEF_WPAGE];
+		break;
+	default:
+		goto out;
+	}
+
+	if (iocg->cursor) {
+		seek_pages = abs(bio->bi_iter.bi_sector - iocg->cursor);
+		seek_pages >>= IOC_SECT_TO_PAGE_SHIFT;
+	}
+
+	if (!is_merge) {
+		if (seek_pages > LCOEF_RANDIO_PAGES) {
+			cost += coef_randio;
+		} else {
+			cost += coef_seqio;
+		}
+	}
+	cost += pages * coef_page;
+out:
+	*costp = cost;
+}
+
+static u64 calc_vtime_cost(struct bio *bio, struct ioc_gq *iocg, bool is_merge)
+{
+	u64 cost;
+
+	calc_vtime_cost_builtin(bio, iocg, is_merge, &cost);
+	return cost;
+}
+
+static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
+{
+	struct blkcg_gq *blkg = bio->bi_blkg;
+	struct ioc *ioc = rqos_to_ioc(rqos);
+	struct ioc_gq *iocg = blkg_to_iocg(blkg);
+	struct ioc_now now;
+	struct iocg_wait wait;
+	u32 hw_active, hw_inuse;
+	u64 abs_cost, cost, vtime;
+
+	/* bypass IOs if disabled or for root cgroup */
+	if (!ioc->enabled || !iocg->level)
+		return;
+
+	/* always activate so that even 0 cost IOs get protected to some level */
+	if (!iocg_activate(iocg, &now))
+		return;
+
+	/* calculate the absolute vtime cost */
+	abs_cost = calc_vtime_cost(bio, iocg, false);
+	if (!abs_cost)
+		return;
+
+	iocg->cursor = bio_end_sector(bio);
+
+	vtime = atomic64_read(&iocg->vtime);
+	current_hweight(iocg, &hw_active, &hw_inuse);
+
+	if (hw_inuse < hw_active &&
+	    time_after_eq64(vtime + ioc->inuse_margin_vtime, now.vnow)) {
+		TRACE_IOCG_PATH(inuse_reset, iocg, &now,
+				iocg->inuse, iocg->weight, hw_inuse, hw_active);
+		spin_lock_irq(&ioc->lock);
+		propagate_active_weight(iocg, iocg->weight, iocg->weight);
+		spin_unlock_irq(&ioc->lock);
+		current_hweight(iocg, &hw_active, &hw_inuse);
+	}
+
+	cost = abs_cost_to_cost(abs_cost, hw_inuse);
+
+	/*
+	 * If no one's waiting and within budget, issue right away.  The
+	 * tests are racy but the races aren't systemic - we only miss once
+	 * in a while which is fine.
+	 */
+	if (!waitqueue_active(&iocg->waitq) &&
+	    time_before_eq64(vtime + cost, now.vnow)) {
+		iocg_commit_bio(iocg, bio, cost);
+		return;
+	}
+
+	if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) {
+		iocg_commit_bio(iocg, bio, cost);
+		iocg_kick_delay(iocg, &now, cost);
+		return;
+	}
+
+	/*
+	 * Append self to the waitq and schedule the wakeup timer if we're
+	 * the first waiter.  The timer duration is calculated based on the
+	 * current vrate.  vtime and hweight changes can make it too short
+	 * or too long.  Each wait entry records the absolute cost it's
+	 * waiting for to allow re-evaluation using a custom wait entry.
+	 *
+	 * If too short, the timer simply reschedules itself.  If too long,
+	 * the period timer will notice and trigger wakeups.
+	 *
+	 * All waiters are on iocg->waitq and the wait states are
+	 * synchronized using waitq.lock.
+	 */
+	spin_lock_irq(&iocg->waitq.lock);
+
+	/*
+	 * We activated above but w/o any synchronization.  Deactivation is
+	 * synchronized with waitq.lock and we won't get deactivated as
+	 * long as we're waiting, so we're good if we're activated here.
+	 * In the unlikely case that we are deactivated, just issue the IO.
+	 */
+	if (unlikely(list_empty(&iocg->active_list))) {
+		spin_unlock_irq(&iocg->waitq.lock);
+		iocg_commit_bio(iocg, bio, cost);
+		return;
+	}
+
+	init_waitqueue_func_entry(&wait.wait, iocg_wake_fn);
+	wait.wait.private = current;
+	wait.bio = bio;
+	wait.abs_cost = abs_cost;
+	wait.committed = false;	/* will be set true by waker */
+
+	__add_wait_queue_entry_tail(&iocg->waitq, &wait.wait);
+	iocg_kick_waitq(iocg, &now);
+
+	spin_unlock_irq(&iocg->waitq.lock);
+
+	while (true) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		if (wait.committed)
+			break;
+		io_schedule();
+	}
+
+	/* waker already committed us, proceed */
+	finish_wait(&iocg->waitq, &wait.wait);
+}
+
+static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq,
+			   struct bio *bio)
+{
+	struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg);
+	sector_t bio_end = bio_end_sector(bio);
+	u32 hw_inuse;
+	u64 abs_cost, cost;
+
+	/* add iff the existing request has cost assigned */
+	if (!rq->bio || !rq->bio->bi_iocost_cost)
+		return;
+
+	abs_cost = calc_vtime_cost(bio, iocg, true);
+	if (!abs_cost)
+		return;
+
+	/* update cursor if backmerging into the request at the cursor */
+	if (blk_rq_pos(rq) < bio_end &&
+	    blk_rq_pos(rq) + blk_rq_sectors(rq) == iocg->cursor)
+		iocg->cursor = bio_end;
+
+	current_hweight(iocg, NULL, &hw_inuse);
+	cost = div64_u64(abs_cost * HWEIGHT_WHOLE, hw_inuse);
+	bio->bi_iocost_cost = cost;
+
+	atomic64_add(cost, &iocg->vtime);
+}
+
+static void ioc_rqos_done_bio(struct rq_qos *rqos, struct bio *bio)
+{
+	struct ioc_gq *iocg = blkg_to_iocg(bio->bi_blkg);
+
+	if (iocg && bio->bi_iocost_cost)
+		atomic64_add(bio->bi_iocost_cost, &iocg->done_vtime);
+}
+
+static void ioc_rqos_done(struct rq_qos *rqos, struct request *rq)
+{
+	struct ioc *ioc = rqos_to_ioc(rqos);
+	u64 on_q_ns, rq_wait_ns;
+	int pidx, rw;
+
+	if (!ioc->enabled || !rq->pre_start_time_ns || !rq->start_time_ns)
+		return;
+
+	switch (req_op(rq) & REQ_OP_MASK) {
+	case REQ_OP_READ:
+		pidx = QOS_RLAT;
+		rw = READ;
+		break;
+	case REQ_OP_WRITE:
+		pidx = QOS_WLAT;
+		rw = WRITE;
+		break;
+	default:
+		return;
+	}
+
+	on_q_ns = ktime_get_ns() - rq->pre_start_time_ns;
+	rq_wait_ns = rq->start_time_ns - rq->pre_start_time_ns;
+
+	if (on_q_ns <= ioc->params.qos[pidx] * NSEC_PER_USEC)
+		this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_met);
+	else
+		this_cpu_inc(ioc->pcpu_stat->missed[rw].nr_missed);
+
+	this_cpu_add(ioc->pcpu_stat->rq_wait_ns, rq_wait_ns);
+}
+
+static void ioc_rqos_queue_depth_changed(struct rq_qos *rqos)
+{
+	struct ioc *ioc = rqos_to_ioc(rqos);
+
+	spin_lock_irq(&ioc->lock);
+	ioc_refresh_params(ioc, false);
+	spin_unlock_irq(&ioc->lock);
+}
+
+static void ioc_rqos_exit(struct rq_qos *rqos)
+{
+	struct ioc *ioc = rqos_to_ioc(rqos);
+
+	blkcg_deactivate_policy(rqos->q, &blkcg_policy_iocost);
+
+	spin_lock_irq(&ioc->lock);
+	ioc->running = IOC_STOP;
+	spin_unlock_irq(&ioc->lock);
+
+	del_timer_sync(&ioc->timer);
+	free_percpu(ioc->pcpu_stat);
+	kfree(ioc);
+}
+
+static struct rq_qos_ops ioc_rqos_ops = {
+	.throttle = ioc_rqos_throttle,
+	.merge = ioc_rqos_merge,
+	.done_bio = ioc_rqos_done_bio,
+	.done = ioc_rqos_done,
+	.queue_depth_changed = ioc_rqos_queue_depth_changed,
+	.exit = ioc_rqos_exit,
+};
+
+static int blk_iocost_init(struct request_queue *q)
+{
+	struct ioc *ioc;
+	struct rq_qos *rqos;
+	int ret;
+
+	ioc = kzalloc(sizeof(*ioc), GFP_KERNEL);
+	if (!ioc)
+		return -ENOMEM;
+
+	ioc->pcpu_stat = alloc_percpu(struct ioc_pcpu_stat);
+	if (!ioc->pcpu_stat) {
+		kfree(ioc);
+		return -ENOMEM;
+	}
+
+	rqos = &ioc->rqos;
+	rqos->id = RQ_QOS_COST;
+	rqos->ops = &ioc_rqos_ops;
+	rqos->q = q;
+
+	spin_lock_init(&ioc->lock);
+	timer_setup(&ioc->timer, ioc_timer_fn, 0);
+	INIT_LIST_HEAD(&ioc->active_iocgs);
+
+	ioc->running = IOC_IDLE;
+	atomic64_set(&ioc->vtime_rate, VTIME_PER_USEC);
+	seqcount_init(&ioc->period_seqcount);
+	ioc->period_at = ktime_to_us(ktime_get());
+	atomic64_set(&ioc->cur_period, 0);
+	atomic_set(&ioc->hweight_gen, 0);
+
+	spin_lock_irq(&ioc->lock);
+	ioc->autop_idx = AUTOP_INVALID;
+	ioc_refresh_params(ioc, true);
+	spin_unlock_irq(&ioc->lock);
+
+	rq_qos_add(q, rqos);
+	ret = blkcg_activate_policy(q, &blkcg_policy_iocost);
+	if (ret) {
+		rq_qos_del(q, rqos);
+		kfree(ioc);
+		return ret;
+	}
+	return 0;
+}
+
+static struct blkcg_policy_data *ioc_cpd_alloc(gfp_t gfp)
+{
+	struct ioc_cgrp *iocc;
+
+	iocc = kzalloc(sizeof(struct ioc_cgrp), gfp);
+	iocc->dfl_weight = CGROUP_WEIGHT_DFL;
+
+	return &iocc->cpd;
+}
+
+static void ioc_cpd_free(struct blkcg_policy_data *cpd)
+{
+	kfree(container_of(cpd, struct ioc_cgrp, cpd));
+}
+
+static struct blkg_policy_data *ioc_pd_alloc(gfp_t gfp, struct request_queue *q,
+					     struct blkcg *blkcg)
+{
+	int levels = blkcg->css.cgroup->level + 1;
+	struct ioc_gq *iocg;
+
+	iocg = kzalloc_node(sizeof(*iocg) + levels * sizeof(iocg->ancestors[0]),
+			    gfp, q->node);
+	if (!iocg)
+		return NULL;
+
+	return &iocg->pd;
+}
+
+static void ioc_pd_init(struct blkg_policy_data *pd)
+{
+	struct ioc_gq *iocg = pd_to_iocg(pd);
+	struct blkcg_gq *blkg = pd_to_blkg(&iocg->pd);
+	struct ioc *ioc = q_to_ioc(blkg->q);
+	struct ioc_now now;
+	struct blkcg_gq *tblkg;
+	unsigned long flags;
+
+	ioc_now(ioc, &now);
+
+	iocg->ioc = ioc;
+	atomic64_set(&iocg->vtime, now.vnow);
+	atomic64_set(&iocg->done_vtime, now.vnow);
+	atomic64_set(&iocg->active_period, atomic64_read(&ioc->cur_period));
+	INIT_LIST_HEAD(&iocg->active_list);
+	iocg->hweight_active = HWEIGHT_WHOLE;
+	iocg->hweight_inuse = HWEIGHT_WHOLE;
+
+	init_waitqueue_head(&iocg->waitq);
+	hrtimer_init(&iocg->waitq_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	iocg->waitq_timer.function = iocg_waitq_timer_fn;
+	hrtimer_init(&iocg->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	iocg->delay_timer.function = iocg_delay_timer_fn;
+
+	iocg->level = blkg->blkcg->css.cgroup->level;
+
+	for (tblkg = blkg; tblkg; tblkg = tblkg->parent) {
+		struct ioc_gq *tiocg = blkg_to_iocg(tblkg);
+		iocg->ancestors[tiocg->level] = tiocg;
+	}
+
+	spin_lock_irqsave(&ioc->lock, flags);
+	weight_updated(iocg);
+	spin_unlock_irqrestore(&ioc->lock, flags);
+}
+
+static void ioc_pd_free(struct blkg_policy_data *pd)
+{
+	struct ioc_gq *iocg = pd_to_iocg(pd);
+	struct ioc *ioc = iocg->ioc;
+
+	if (ioc) {
+		hrtimer_cancel(&iocg->waitq_timer);
+		hrtimer_cancel(&iocg->delay_timer);
+
+		spin_lock(&ioc->lock);
+		if (!list_empty(&iocg->active_list)) {
+			propagate_active_weight(iocg, 0, 0);
+			list_del_init(&iocg->active_list);
+		}
+		spin_unlock(&ioc->lock);
+	}
+	kfree(iocg);
+}
+
+static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd,
+			     int off)
+{
+	const char *dname = blkg_dev_name(pd->blkg);
+	struct ioc_gq *iocg = pd_to_iocg(pd);
+
+	if (dname && iocg->cfg_weight)
+		seq_printf(sf, "%s %u\n", dname, iocg->cfg_weight);
+	return 0;
+}
+
+
+static int ioc_weight_show(struct seq_file *sf, void *v)
+{
+	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+	struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg);
+
+	seq_printf(sf, "default %u\n", iocc->dfl_weight);
+	blkcg_print_blkgs(sf, blkcg, ioc_weight_prfill,
+			  &blkcg_policy_iocost, seq_cft(sf)->private, false);
+	return 0;
+}
+
+static ssize_t ioc_weight_write(struct kernfs_open_file *of, char *buf,
+				size_t nbytes, loff_t off)
+{
+	struct blkcg *blkcg = css_to_blkcg(of_css(of));
+	struct ioc_cgrp *iocc = blkcg_to_iocc(blkcg);
+	struct blkg_conf_ctx ctx;
+	struct ioc_gq *iocg;
+	u32 v;
+	int ret;
+
+	if (!strchr(buf, ':')) {
+		struct blkcg_gq *blkg;
+
+		if (!sscanf(buf, "default %u", &v) && !sscanf(buf, "%u", &v))
+			return -EINVAL;
+
+		if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX)
+			return -EINVAL;
+
+		spin_lock(&blkcg->lock);
+		iocc->dfl_weight = v;
+		hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
+			struct ioc_gq *iocg = blkg_to_iocg(blkg);
+
+			if (iocg) {
+				spin_lock_irq(&iocg->ioc->lock);
+				weight_updated(iocg);
+				spin_unlock_irq(&iocg->ioc->lock);
+			}
+		}
+		spin_unlock(&blkcg->lock);
+
+		return nbytes;
+	}
+
+	ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, buf, &ctx);
+	if (ret)
+		return ret;
+
+	iocg = blkg_to_iocg(ctx.blkg);
+
+	if (!strncmp(ctx.body, "default", 7)) {
+		v = 0;
+	} else {
+		if (!sscanf(ctx.body, "%u", &v))
+			goto einval;
+		if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX)
+			goto einval;
+	}
+
+	spin_lock_irq(&iocg->ioc->lock);
+	iocg->cfg_weight = v;
+	weight_updated(iocg);
+	spin_unlock_irq(&iocg->ioc->lock);
+
+	blkg_conf_finish(&ctx);
+	return nbytes;
+
+einval:
+	blkg_conf_finish(&ctx);
+	return -EINVAL;
+}
+
+static u64 ioc_qos_prfill(struct seq_file *sf, struct blkg_policy_data *pd,
+			  int off)
+{
+	const char *dname = blkg_dev_name(pd->blkg);
+	struct ioc *ioc = pd_to_iocg(pd)->ioc;
+
+	if (!dname)
+		return 0;
+
+	seq_printf(sf, "%s enable=%d ctrl=%s rpct=%u.%02u rlat=%u wpct=%u.%02u wlat=%u min=%u.%02u max=%u.%02u\n",
+		   dname, ioc->enabled, ioc->user_qos_params ? "user" : "auto",
+		   ioc->params.qos[QOS_RPPM] / 10000,
+		   ioc->params.qos[QOS_RPPM] % 10000 / 100,
+		   ioc->params.qos[QOS_RLAT],
+		   ioc->params.qos[QOS_WPPM] / 10000,
+		   ioc->params.qos[QOS_WPPM] % 10000 / 100,
+		   ioc->params.qos[QOS_WLAT],
+		   ioc->params.qos[QOS_MIN] / 10000,
+		   ioc->params.qos[QOS_MIN] % 10000 / 100,
+		   ioc->params.qos[QOS_MAX] / 10000,
+		   ioc->params.qos[QOS_MAX] % 10000 / 100);
+	return 0;
+}
+
+static int ioc_qos_show(struct seq_file *sf, void *v)
+{
+	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+
+	blkcg_print_blkgs(sf, blkcg, ioc_qos_prfill,
+			  &blkcg_policy_iocost, seq_cft(sf)->private, false);
+	return 0;
+}
+
+static const match_table_t qos_ctrl_tokens = {
+	{ QOS_ENABLE,		"enable=%u"	},
+	{ QOS_CTRL,		"ctrl=%s"	},
+	{ NR_QOS_CTRL_PARAMS,	NULL		},
+};
+
+static const match_table_t qos_tokens = {
+	{ QOS_RPPM,		"rpct=%s"	},
+	{ QOS_RLAT,		"rlat=%u"	},
+	{ QOS_WPPM,		"wpct=%s"	},
+	{ QOS_WLAT,		"wlat=%u"	},
+	{ QOS_MIN,		"min=%s"	},
+	{ QOS_MAX,		"max=%s"	},
+	{ NR_QOS_PARAMS,	NULL		},
+};
+
+static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
+			     size_t nbytes, loff_t off)
+{
+	struct gendisk *disk;
+	struct ioc *ioc;
+	u32 qos[NR_QOS_PARAMS];
+	bool enable, user;
+	char *p;
+	int ret;
+
+	disk = blkcg_conf_get_disk(&input);
+	if (IS_ERR(disk))
+		return PTR_ERR(disk);
+
+	ioc = q_to_ioc(disk->queue);
+	if (!ioc) {
+		ret = blk_iocost_init(disk->queue);
+		if (ret)
+			goto err;
+		ioc = q_to_ioc(disk->queue);
+	}
+
+	spin_lock_irq(&ioc->lock);
+	memcpy(qos, ioc->params.qos, sizeof(qos));
+	enable = ioc->enabled;
+	user = ioc->user_qos_params;
+	spin_unlock_irq(&ioc->lock);
+
+	while ((p = strsep(&input, " \t\n"))) {
+		substring_t args[MAX_OPT_ARGS];
+		char buf[32];
+		int tok;
+		s64 v;
+
+		if (!*p)
+			continue;
+
+		switch (match_token(p, qos_ctrl_tokens, args)) {
+		case QOS_ENABLE:
+			match_u64(&args[0], &v);
+			enable = v;
+			continue;
+		case QOS_CTRL:
+			match_strlcpy(buf, &args[0], sizeof(buf));
+			if (!strcmp(buf, "auto"))
+				user = false;
+			else if (!strcmp(buf, "user"))
+				user = true;
+			else
+				goto einval;
+			continue;
+		}
+
+		tok = match_token(p, qos_tokens, args);
+		switch (tok) {
+		case QOS_RPPM:
+		case QOS_WPPM:
+			if (match_strlcpy(buf, &args[0], sizeof(buf)) >=
+			    sizeof(buf))
+				goto einval;
+			if (cgroup_parse_float(buf, 2, &v))
+				goto einval;
+			if (v < 0 || v > 10000)
+				goto einval;
+			qos[tok] = v * 100;
+			break;
+		case QOS_RLAT:
+		case QOS_WLAT:
+			if (match_u64(&args[0], &v))
+				goto einval;
+			qos[tok] = v;
+			break;
+		case QOS_MIN:
+		case QOS_MAX:
+			if (match_strlcpy(buf, &args[0], sizeof(buf)) >=
+			    sizeof(buf))
+				goto einval;
+			if (cgroup_parse_float(buf, 2, &v))
+				goto einval;
+			if (v < 0)
+				goto einval;
+			qos[tok] = clamp_t(s64, v * 100,
+					   VRATE_MIN_PPM, VRATE_MAX_PPM);
+			break;
+		default:
+			goto einval;
+		}
+		user = true;
+	}
+
+	if (qos[QOS_MIN] > qos[QOS_MAX])
+		goto einval;
+
+	spin_lock_irq(&ioc->lock);
+
+	if (enable) {
+		blk_queue_flag_set(QUEUE_FLAG_REC_PRESTART, ioc->rqos.q);
+		ioc->enabled = true;
+	} else {
+		blk_queue_flag_clear(QUEUE_FLAG_REC_PRESTART, ioc->rqos.q);
+		ioc->enabled = false;
+	}
+
+	if (user) {
+		memcpy(ioc->params.qos, qos, sizeof(qos));
+		ioc->user_qos_params = true;
+	} else {
+		ioc->user_qos_params = false;
+	}
+
+	ioc_refresh_params(ioc, true);
+	spin_unlock_irq(&ioc->lock);
+
+	put_disk_and_module(disk);
+	return nbytes;
+einval:
+	ret = -EINVAL;
+err:
+	put_disk_and_module(disk);
+	return ret;
+}
+
+static u64 ioc_cost_model_prfill(struct seq_file *sf,
+				 struct blkg_policy_data *pd, int off)
+{
+	const char *dname = blkg_dev_name(pd->blkg);
+	struct ioc *ioc = pd_to_iocg(pd)->ioc;
+	u64 *u = ioc->params.i_lcoefs;
+
+	if (!dname)
+		return 0;
+
+	seq_printf(sf, "%s ctrl=%s model=linear "
+		   "rbps=%llu rseqiops=%llu rrandiops=%llu "
+		   "wbps=%llu wseqiops=%llu wrandiops=%llu\n",
+		   dname, ioc->user_cost_model ? "user" : "auto",
+		   u[I_LCOEF_RBPS], u[I_LCOEF_RSEQIOPS], u[I_LCOEF_RRANDIOPS],
+		   u[I_LCOEF_WBPS], u[I_LCOEF_WSEQIOPS], u[I_LCOEF_WRANDIOPS]);
+	return 0;
+}
+
+static int ioc_cost_model_show(struct seq_file *sf, void *v)
+{
+	struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+
+	blkcg_print_blkgs(sf, blkcg, ioc_cost_model_prfill,
+			  &blkcg_policy_iocost, seq_cft(sf)->private, false);
+	return 0;
+}
+
+static const match_table_t cost_ctrl_tokens = {
+	{ COST_CTRL,		"ctrl=%s"	},
+	{ COST_MODEL,		"model=%s"	},
+	{ NR_COST_CTRL_PARAMS,	NULL		},
+};
+
+static const match_table_t i_lcoef_tokens = {
+	{ I_LCOEF_RBPS,		"rbps=%u"	},
+	{ I_LCOEF_RSEQIOPS,	"rseqiops=%u"	},
+	{ I_LCOEF_RRANDIOPS,	"rrandiops=%u"	},
+	{ I_LCOEF_WBPS,		"wbps=%u"	},
+	{ I_LCOEF_WSEQIOPS,	"wseqiops=%u"	},
+	{ I_LCOEF_WRANDIOPS,	"wrandiops=%u"	},
+	{ NR_I_LCOEFS,		NULL		},
+};
+
+static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
+				    size_t nbytes, loff_t off)
+{
+	struct gendisk *disk;
+	struct ioc *ioc;
+	u64 u[NR_I_LCOEFS];
+	bool user;
+	char *p;
+	int ret;
+
+	disk = blkcg_conf_get_disk(&input);
+	if (IS_ERR(disk))
+		return PTR_ERR(disk);
+
+	ioc = q_to_ioc(disk->queue);
+	if (!ioc) {
+		ret = blk_iocost_init(disk->queue);
+		if (ret)
+			goto err;
+		ioc = q_to_ioc(disk->queue);
+	}
+
+	spin_lock_irq(&ioc->lock);
+	memcpy(u, ioc->params.i_lcoefs, sizeof(u));
+	user = ioc->user_cost_model;
+	spin_unlock_irq(&ioc->lock);
+
+	while ((p = strsep(&input, " \t\n"))) {
+		substring_t args[MAX_OPT_ARGS];
+		char buf[32];
+		int tok;
+		u64 v;
+
+		if (!*p)
+			continue;
+
+		switch (match_token(p, cost_ctrl_tokens, args)) {
+		case COST_CTRL:
+			match_strlcpy(buf, &args[0], sizeof(buf));
+			if (!strcmp(buf, "auto"))
+				user = false;
+			else if (!strcmp(buf, "user"))
+				user = true;
+			else
+				goto einval;
+			continue;
+		case COST_MODEL:
+			match_strlcpy(buf, &args[0], sizeof(buf));
+			if (strcmp(buf, "linear"))
+				goto einval;
+			continue;
+		}
+
+		tok = match_token(p, i_lcoef_tokens, args);
+		if (tok == NR_I_LCOEFS)
+			goto einval;
+		if (match_u64(&args[0], &v))
+			goto einval;
+		u[tok] = v;
+		user = true;
+	}
+
+	spin_lock_irq(&ioc->lock);
+	if (user) {
+		memcpy(ioc->params.i_lcoefs, u, sizeof(u));
+		ioc->user_cost_model = true;
+	} else {
+		ioc->user_cost_model = false;
+	}
+	ioc_refresh_params(ioc, true);
+	spin_unlock_irq(&ioc->lock);
+
+	put_disk_and_module(disk);
+	return nbytes;
+
+einval:
+	ret = -EINVAL;
+err:
+	put_disk_and_module(disk);
+	return ret;
+}
+
+static struct cftype ioc_files[] = {
+	{
+		.name = "weight",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = ioc_weight_show,
+		.write = ioc_weight_write,
+	},
+	{
+		.name = "cost.qos",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.seq_show = ioc_qos_show,
+		.write = ioc_qos_write,
+	},
+	{
+		.name = "cost.model",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.seq_show = ioc_cost_model_show,
+		.write = ioc_cost_model_write,
+	},
+	{}
+};
+
+static struct blkcg_policy blkcg_policy_iocost = {
+	.dfl_cftypes	= ioc_files,
+	.cpd_alloc_fn	= ioc_cpd_alloc,
+	.cpd_free_fn	= ioc_cpd_free,
+	.pd_alloc_fn	= ioc_pd_alloc,
+	.pd_init_fn	= ioc_pd_init,
+	.pd_free_fn	= ioc_pd_free,
+};
+
+static int __init ioc_init(void)
+{
+	return blkcg_policy_register(&blkcg_policy_iocost);
+}
+
+static void __exit ioc_exit(void)
+{
+	return blkcg_policy_unregister(&blkcg_policy_iocost);
+}
+
+module_init(ioc_init);
+module_exit(ioc_exit);
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 5f8b75826a98..08a09dbe0f4b 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -15,6 +15,7 @@ struct blk_mq_debugfs_attr;
 enum rq_qos_id {
 	RQ_QOS_WBT,
 	RQ_QOS_LATENCY,
+	RQ_QOS_COST,
 };
 
 struct rq_wait {
@@ -84,6 +85,8 @@ static inline const char *rq_qos_id_to_name(enum rq_qos_id id)
 		return "wbt";
 	case RQ_QOS_LATENCY:
 		return "latency";
+	case RQ_QOS_COST:
+		return "cost";
 	}
 	return "unknown";
 }
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index feff3fe4467e..e53e84bf83a6 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -169,6 +169,9 @@ struct bio {
 	 */
 	struct blkcg_gq		*bi_blkg;
 	struct bio_issue	bi_issue;
+#ifdef CONFIG_BLK_CGROUP_IOCOST
+	u64			bi_iocost_cost;
+#endif
 #endif
 	union {
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h
new file mode 100644
index 000000000000..ec2217dd57ac
--- /dev/null
+++ b/include/trace/events/iocost.h
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM iocost
+
+#if !defined(_TRACE_BLK_IOCOST_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BLK_IOCOST_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(iocost_iocg_activate,
+
+	TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+		u64 last_period, u64 cur_period, u64 vtime),
+
+	TP_ARGS(iocg, path, now, last_period, cur_period, vtime),
+
+	TP_STRUCT__entry (
+		__string(devname, ioc_name(iocg->ioc))
+		__string(cgroup, path)
+		__field(u64, now)
+		__field(u64, vnow)
+		__field(u64, vrate)
+		__field(u64, last_period)
+		__field(u64, cur_period)
+		__field(u64, last_vtime)
+		__field(u64, vtime)
+		__field(u32, weight)
+		__field(u32, inuse)
+		__field(u64, hweight_active)
+		__field(u64, hweight_inuse)
+	),
+
+	TP_fast_assign(
+		__assign_str(devname, ioc_name(iocg->ioc));
+		__assign_str(cgroup, path);
+		__entry->now = now->now;
+		__entry->vnow = now->vnow;
+		__entry->vrate = now->vrate;
+		__entry->last_period = last_period;
+		__entry->cur_period = cur_period;
+		__entry->last_vtime = iocg->last_vtime;
+		__entry->vtime = vtime;
+		__entry->weight = iocg->weight;
+		__entry->inuse = iocg->inuse;
+		__entry->hweight_active = iocg->hweight_active;
+		__entry->hweight_inuse = iocg->hweight_inuse;
+	),
+
+	TP_printk("[%s:%s] now=%llu:%llu vrate=%llu "
+		  "period=%llu->%llu vtime=%llu->%llu "
+		  "weight=%u/%u hweight=%llu/%llu",
+		__get_str(devname), __get_str(cgroup),
+		__entry->now, __entry->vnow, __entry->vrate,
+		__entry->last_period, __entry->cur_period,
+		__entry->last_vtime, __entry->vtime,
+		__entry->inuse, __entry->weight,
+		__entry->hweight_inuse, __entry->hweight_active
+	)
+);
+
+DECLARE_EVENT_CLASS(iocg_inuse_update,
+
+	TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+		u32 old_inuse, u32 new_inuse,
+		u64 old_hw_inuse, u64 new_hw_inuse),
+
+	TP_ARGS(iocg, path, now, old_inuse, new_inuse,
+		old_hw_inuse, new_hw_inuse),
+
+	TP_STRUCT__entry (
+		__string(devname, ioc_name(iocg->ioc))
+		__string(cgroup, path)
+		__field(u64, now)
+		__field(u32, old_inuse)
+		__field(u32, new_inuse)
+		__field(u64, old_hweight_inuse)
+		__field(u64, new_hweight_inuse)
+	),
+
+	TP_fast_assign(
+		__assign_str(devname, ioc_name(iocg->ioc));
+		__assign_str(cgroup, path);
+		__entry->now = now->now;
+		__entry->old_inuse = old_inuse;
+		__entry->new_inuse = new_inuse;
+		__entry->old_hweight_inuse = old_hw_inuse;
+		__entry->new_hweight_inuse = new_hw_inuse;
+	),
+
+	TP_printk("[%s:%s] now=%llu inuse=%u->%u hw_inuse=%llu->%llu",
+		__get_str(devname), __get_str(cgroup), __entry->now,
+		__entry->old_inuse, __entry->new_inuse,
+		__entry->old_hweight_inuse, __entry->new_hweight_inuse
+	)
+);
+
+DEFINE_EVENT(iocg_inuse_update, iocost_inuse_takeback,
+
+	TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+		u32 old_inuse, u32 new_inuse,
+		u64 old_hw_inuse, u64 new_hw_inuse),
+
+	TP_ARGS(iocg, path, now, old_inuse, new_inuse,
+		old_hw_inuse, new_hw_inuse)
+);
+
+DEFINE_EVENT(iocg_inuse_update, iocost_inuse_giveaway,
+
+	TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+		u32 old_inuse, u32 new_inuse,
+		u64 old_hw_inuse, u64 new_hw_inuse),
+
+	TP_ARGS(iocg, path, now, old_inuse, new_inuse,
+		old_hw_inuse, new_hw_inuse)
+);
+
+DEFINE_EVENT(iocg_inuse_update, iocost_inuse_reset,
+
+	TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+		u32 old_inuse, u32 new_inuse,
+		u64 old_hw_inuse, u64 new_hw_inuse),
+
+	TP_ARGS(iocg, path, now, old_inuse, new_inuse,
+		old_hw_inuse, new_hw_inuse)
+);
+
+TRACE_EVENT(iocost_ioc_vrate_adj,
+
+	TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 (*missed_ppm)[2],
+		u32 rq_wait_pct, int nr_lagging, int nr_shortages,
+		int nr_surpluses),
+
+	TP_ARGS(ioc, new_vrate, missed_ppm, rq_wait_pct, nr_lagging, nr_shortages,
+		nr_surpluses),
+
+	TP_STRUCT__entry (
+		__string(devname, ioc_name(ioc))
+		__field(u64, old_vrate)
+		__field(u64, new_vrate)
+		__field(int, busy_level)
+		__field(u32, read_missed_ppm)
+		__field(u32, write_missed_ppm)
+		__field(u32, rq_wait_pct)
+		__field(int, nr_lagging)
+		__field(int, nr_shortages)
+		__field(int, nr_surpluses)
+	),
+
+	TP_fast_assign(
+		__assign_str(devname, ioc_name(ioc));
+		__entry->old_vrate = atomic64_read(&ioc->vtime_rate);;
+		__entry->new_vrate = new_vrate;
+		__entry->busy_level = ioc->busy_level;
+		__entry->read_missed_ppm = (*missed_ppm)[READ];
+		__entry->write_missed_ppm = (*missed_ppm)[WRITE];
+		__entry->rq_wait_pct = rq_wait_pct;
+		__entry->nr_lagging = nr_lagging;
+		__entry->nr_shortages = nr_shortages;
+		__entry->nr_surpluses = nr_surpluses;
+	),
+
+	TP_printk("[%s] vrate=%llu->%llu busy=%d missed_ppm=%u:%u rq_wait_pct=%u lagging=%d shortages=%d surpluses=%d",
+		__get_str(devname), __entry->old_vrate, __entry->new_vrate,
+		__entry->busy_level,
+		__entry->read_missed_ppm, __entry->write_missed_ppm,
+		__entry->rq_wait_pct, __entry->nr_lagging, __entry->nr_shortages,
+		__entry->nr_surpluses
+	)
+);
+
+#endif /* _TRACE_BLK_IOCOST_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
