--- /dev/null
+/* 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);
+
+ /* we can race with deactivations and either may read as zero */
+ if (!active_sum || !inuse_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->alloc_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->alloc_time_ns;
+ rq_wait_ns = rq->start_time_ns - rq->alloc_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_RQ_ALLOC_TIME, ioc->rqos.q);
+ ioc->enabled = true;
+ } else {
+ blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, 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);
projects / openwrt / staging / blogic.git / commitdiff