[PATCH 20/30] block: remove legacy IO schedulers

Jens Axboe
2018-10-31T17:59:12Z

Retain the deadline documentation, as that carries over to mq-deadline
as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
Documentation/block/cfq-iosched.txt | 291 --
block/Kconfig.iosched | 61 -
block/Makefile | 3 -
block/cfq-iosched.c | 4916 ---------------------------
block/deadline-iosched.c | 560 ---
block/elevator.c | 70 -
block/noop-iosched.c | 124 -
7 files changed, 6025 deletions(-)
delete mode 100644 Documentation/block/cfq-iosched.txt
delete mode 100644 block/cfq-iosched.c
delete mode 100644 block/deadline-iosched.c
delete mode 100644 block/noop-iosched.c

diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt
deleted file mode 100644
index 895bd3813115..000000000000
--- a/Documentation/block/cfq-iosched.txt
+++ /dev/null
@@ -1,291 +0,0 @@
-CFQ (Complete Fairness Queueing)
-===============================
-
-The main aim of CFQ scheduler is to provide a fair allocation of the disk
-I/O bandwidth for all the processes which requests an I/O operation.
-
-CFQ maintains the per process queue for the processes which request I/O
-operation(synchronous requests). In case of asynchronous requests, all the
-requests from all the processes are batched together according to their
-process's I/O priority.
-
-CFQ ioscheduler tunables
-========================
-
-slice_idle
-----------
-This specifies how long CFQ should idle for next request on certain cfq queues
-(for sequential workloads) and service trees (for random workloads) before
-queue is expired and CFQ selects next queue to dispatch from.
-
-By default slice_idle is a non-zero value. That means by default we idle on
-queues/service trees. This can be very helpful on highly seeky media like
-single spindle SATA/SAS disks where we can cut down on overall number of
-seeks and see improved throughput.
-
-Setting slice_idle to 0 will remove all the idling on queues/service tree
-level and one should see an overall improved throughput on faster storage
-devices like multiple SATA/SAS disks in hardware RAID configuration. The down
-side is that isolation provided from WRITES also goes down and notion of
-IO priority becomes weaker.
-
-So depending on storage and workload, it might be useful to set slice_idle=0.
-In general I think for SATA/SAS disks and software RAID of SATA/SAS disks
-keeping slice_idle enabled should be useful. For any configurations where
-there are multiple spindles behind single LUN (Host based hardware RAID
-controller or for storage arrays), setting slice_idle=0 might end up in better
-throughput and acceptable latencies.
-
-back_seek_max
--------------
-This specifies, given in Kbytes, the maximum "distance" for backward seeking.
-The distance is the amount of space from the current head location to the
-sectors that are backward in terms of distance.
-
-This parameter allows the scheduler to anticipate requests in the "backward"
-direction and consider them as being the "next" if they are within this
-distance from the current head location.
-
-back_seek_penalty
------------------
-This parameter is used to compute the cost of backward seeking. If the
-backward distance of request is just 1/back_seek_penalty from a "front"
-request, then the seeking cost of two requests is considered equivalent.
-
-So scheduler will not bias toward one or the other request (otherwise scheduler
-will bias toward front request). Default value of back_seek_penalty is 2.
-
-fifo_expire_async
------------------
-This parameter is used to set the timeout of asynchronous requests. Default
-value of this is 248ms.
-
-fifo_expire_sync
-----------------
-This parameter is used to set the timeout of synchronous requests. Default
-value of this is 124ms. In case to favor synchronous requests over asynchronous
-one, this value should be decreased relative to fifo_expire_async.
-
-group_idle
------------
-This parameter forces idling at the CFQ group level instead of CFQ
-queue level. This was introduced after a bottleneck was observed
-in higher end storage due to idle on sequential queue and allow dispatch
-from a single queue. The idea with this parameter is that it can be run with
-slice_idle=0 and group_idle=8, so that idling does not happen on individual
-queues in the group but happens overall on the group and thus still keeps the
-IO controller working.
-Not idling on individual queues in the group will dispatch requests from
-multiple queues in the group at the same time and achieve higher throughput
-on higher end storage.
-
-Default value for this parameter is 8ms.
-
-low_latency
------------
-This parameter is used to enable/disable the low latency mode of the CFQ
-scheduler. If enabled, CFQ tries to recompute the slice time for each process
-based on the target_latency set for the system. This favors fairness over
-throughput. Disabling low latency (setting it to 0) ignores target latency,
-allowing each process in the system to get a full time slice.
-
-By default low latency mode is enabled.
-
-target_latency
---------------
-This parameter is used to calculate the time slice for a process if cfq's
-latency mode is enabled. It will ensure that sync requests have an estimated
-latency. But if sequential workload is higher(e.g. sequential read),
-then to meet the latency constraints, throughput may decrease because of less
-time for each process to issue I/O request before the cfq queue is switched.
-
-Though this can be overcome by disabling the latency_mode, it may increase
-the read latency for some applications. This parameter allows for changing
-target_latency through the sysfs interface which can provide the balanced
-throughput and read latency.
-
-Default value for target_latency is 300ms.
-
-slice_async
------------
-This parameter is same as of slice_sync but for asynchronous queue. The
-default value is 40ms.
-
-slice_async_rq
---------------
-This parameter is used to limit the dispatching of asynchronous request to
-device request queue in queue's slice time. The maximum number of request that
-are allowed to be dispatched also depends upon the io priority. Default value
-for this is 2.
-
-slice_sync
-----------
-When a queue is selected for execution, the queues IO requests are only
-executed for a certain amount of time(time_slice) before switching to another
-queue. This parameter is used to calculate the time slice of synchronous
-queue.
-
-time_slice is computed using the below equation:-
-time_slice = slice_sync + (slice_sync/5 * (4 - prio)). To increase the
-time_slice of synchronous queue, increase the value of slice_sync. Default
-value is 100ms.
-
-quantum
--------
-This specifies the number of request dispatched to the device queue. In a
-queue's time slice, a request will not be dispatched if the number of request
-in the device exceeds this parameter. This parameter is used for synchronous
-request.
-
-In case of storage with several disk, this setting can limit the parallel
-processing of request. Therefore, increasing the value can improve the
-performance although this can cause the latency of some I/O to increase due
-to more number of requests.
-
-CFQ Group scheduling
-====================
-
-CFQ supports blkio cgroup and has "blkio." prefixed files in each
-blkio cgroup directory. It is weight-based and there are four knobs
-for configuration - weight[_device] and leaf_weight[_device].
-Internal cgroup nodes (the ones with children) can also have tasks in
-them, so the former two configure how much proportion the cgroup as a
-whole is entitled to at its parent's level while the latter two
-configure how much proportion the tasks in the cgroup have compared to
-its direct children.
-
-Another way to think about it is assuming that each internal node has
-an implicit leaf child node which hosts all the tasks whose weight is
-configured by leaf_weight[_device]. Let's assume a blkio hierarchy
-composed of five cgroups - root, A, B, AA and AB - with the following
-weights where the names represent the hierarchy.
-
- weight leaf_weight
- root : 125 125
- A : 500 750
- B : 250 500
- AA : 500 500
- AB : 1000 500
-
-root never has a parent making its weight is meaningless. For backward
-compatibility, weight is always kept in sync with leaf_weight. B, AA
-and AB have no child and thus its tasks have no children cgroup to
-compete with. They always get 100% of what the cgroup won at the
-parent level. Considering only the weights which matter, the hierarchy
-looks like the following.
-
- root
- / | \
- A B leaf
- 500 250 125
- / | \
- AA AB leaf
- 500 1000 750
-
-If all cgroups have active IOs and competing with each other, disk
-time will be distributed like the following.
-
-Distribution below root. The total active weight at this level is
-A:500 + B:250 + C:125 = 875.
-
- root-leaf : 125 / 875 =~ 14%
- A : 500 / 875 =~ 57%
- B(-leaf) : 250 / 875 =~ 28%
-
-A has children and further distributes its 57% among the children and
-the implicit leaf node. The total active weight at this level is
-AA:500 + AB:1000 + A-leaf:750 = 2250.
-
- A-leaf : ( 750 / 2250) * A =~ 19%
- AA(-leaf) : ( 500 / 2250) * A =~ 12%
- AB(-leaf) : (1000 / 2250) * A =~ 25%
-
-CFQ IOPS Mode for group scheduling
-===================================
-Basic CFQ design is to provide priority based time slices. Higher priority
-process gets bigger time slice and lower priority process gets smaller time
-slice. Measuring time becomes harder if storage is fast and supports NCQ and
-it would be better to dispatch multiple requests from multiple cfq queues in
-request queue at a time. In such scenario, it is not possible to measure time
-consumed by single queue accurately.
-
-What is possible though is to measure number of requests dispatched from a
-single queue and also allow dispatch from multiple cfq queue at the same time.
-This effectively becomes the fairness in terms of IOPS (IO operations per
-second).
-
-If one sets slice_idle=0 and if storage supports NCQ, CFQ internally switches
-to IOPS mode and starts providing fairness in terms of number of requests
-dispatched. Note that this mode switching takes effect only for group
-scheduling. For non-cgroup users nothing should change.
-
-CFQ IO scheduler Idling Theory
-===============================
-Idling on a queue is primarily about waiting for the next request to come
-on same queue after completion of a request. In this process CFQ will not
-dispatch requests from other cfq queues even if requests are pending there.
-
-The rationale behind idling is that it can cut down on number of seeks
-on rotational media. For example, if a process is doing dependent
-sequential reads (next read will come on only after completion of previous
-one), then not dispatching request from other queue should help as we
-did not move the disk head and kept on dispatching sequential IO from
-one queue.
-
-CFQ has following service trees and various queues are put on these trees.
-
- sync-idle sync-noidle async
-
-All cfq queues doing synchronous sequential IO go on to sync-idle tree.
-On this tree we idle on each queue individually.
-
-All synchronous non-sequential queues go on sync-noidle tree. Also any
-synchronous write request which is not marked with REQ_IDLE goes on this
-service tree. On this tree we do not idle on individual queues instead idle
-on the whole group of queues or the tree. So if there are 4 queues waiting
-for IO to dispatch we will idle only once last queue has dispatched the IO
-and there is no more IO on this service tree.
-
-All async writes go on async service tree. There is no idling on async
-queues.
-
-CFQ has some optimizations for SSDs and if it detects a non-rotational
-media which can support higher queue depth (multiple requests at in
-flight at a time), then it cuts down on idling of individual queues and
-all the queues move to sync-noidle tree and only tree idle remains. This
-tree idling provides isolation with buffered write queues on async tree.
-
-FAQ
-===
-Q1. Why to idle at all on queues not marked with REQ_IDLE.
-
-A1. We only do tree idle (all queues on sync-noidle tree) on queues not marked
- with REQ_IDLE. This helps in providing isolation with all the sync-idle
- queues. Otherwise in presence of many sequential readers, other
- synchronous IO might not get fair share of disk.
-
- For example, if there are 10 sequential readers doing IO and they get
- 100ms each. If a !REQ_IDLE request comes in, it will be scheduled
- roughly after 1 second. If after completion of !REQ_IDLE request we
- do not idle, and after a couple of milli seconds a another !REQ_IDLE
- request comes in, again it will be scheduled after 1second. Repeat it
- and notice how a workload can lose its disk share and suffer due to
- multiple sequential readers.
-
- fsync can generate dependent IO where bunch of data is written in the
- context of fsync, and later some journaling data is written. Journaling
- data comes in only after fsync has finished its IO (atleast for ext4
- that seemed to be the case). Now if one decides not to idle on fsync
- thread due to !REQ_IDLE, then next journaling write will not get
- scheduled for another second. A process doing small fsync, will suffer
- badly in presence of multiple sequential readers.
-
- Hence doing tree idling on threads using !REQ_IDLE flag on requests
- provides isolation from multiple sequential readers and at the same
- time we do not idle on individual threads.
-
-Q2. When to specify REQ_IDLE
-A2. I would think whenever one is doing synchronous write and expecting
- more writes to be dispatched from same context soon, should be able
- to specify REQ_IDLE on writes and that probably should work well for
- most of the cases.
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index f95a48b0d7b2..4626b88b2d5a 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -3,67 +3,6 @@ if BLOCK

menu "IO Schedulers"

-config IOSCHED_NOOP
- bool
- default y
- ---help---
- The no-op I/O scheduler is a minimal scheduler that does basic merging
- and sorting. Its main uses include non-disk based block devices like
- memory devices, and specialised software or hardware environments
- that do their own scheduling and require only minimal assistance from
- the kernel.
-
-config IOSCHED_DEADLINE
- tristate "Deadline I/O scheduler"
- default y
- ---help---
- The deadline I/O scheduler is simple and compact. It will provide
- CSCAN service with FIFO expiration of requests, switching to
- a new point in the service tree and doing a batch of IO from there
- in case of expiry.
-
-config IOSCHED_CFQ
- tristate "CFQ I/O scheduler"
- default y
- ---help---
- The CFQ I/O scheduler tries to distribute bandwidth equally
- among all processes in the system. It should provide a fair
- and low latency working environment, suitable for both desktop
- and server systems.
-
- This is the default I/O scheduler.
-
-config CFQ_GROUP_IOSCHED
- bool "CFQ Group Scheduling support"
- depends on IOSCHED_CFQ && BLK_CGROUP
- ---help---
- Enable group IO scheduling in CFQ.
-
-choice
-
- prompt "Default I/O scheduler"
- default DEFAULT_CFQ
- help
- Select the I/O scheduler which will be used by default for all
- block devices.
-
- config DEFAULT_DEADLINE
- bool "Deadline" if IOSCHED_DEADLINE=y
-
- config DEFAULT_CFQ
- bool "CFQ" if IOSCHED_CFQ=y
-
- config DEFAULT_NOOP
- bool "No-op"
-
-endchoice
-
-config DEFAULT_IOSCHED
- string
- default "deadline" if DEFAULT_DEADLINE
- default "cfq" if DEFAULT_CFQ
- default "noop" if DEFAULT_NOOP
-
config MQ_IOSCHED_DEADLINE
tristate "MQ deadline I/O scheduler"
default y
diff --git a/block/Makefile b/block/Makefile
index 213674c8faaa..eee1b4ceecf9 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -18,9 +18,6 @@ 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-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
-obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
-obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
obj-$(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/cfq-iosched.c b/block/cfq-iosched.c
deleted file mode 100644
index 6a3d87dd3c1a..000000000000
--- a/block/cfq-iosched.c
+++ /dev/null
@@ -1,4916 +0,0 @@
-/*
- * CFQ, or complete fairness queueing, disk scheduler.
- *
- * Based on ideas from a previously unfinished io
- * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
- *
- * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
- */
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/sched/clock.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/ktime.h>
-#include <linux/rbtree.h>
-#include <linux/ioprio.h>
-#include <linux/blktrace_api.h>
-#include <linux/blk-cgroup.h>
-#include "blk.h"
-#include "blk-wbt.h"
-
-/*
- * tunables
- */
-/* max queue in one round of service */
-static const int cfq_quantum = 8;
-static const u64 cfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
-/* maximum backwards seek, in KiB */
-static const int cfq_back_max = 16 * 1024;
-/* penalty of a backwards seek */
-static const int cfq_back_penalty = 2;
-static const u64 cfq_slice_sync = NSEC_PER_SEC / 10;
-static u64 cfq_slice_async = NSEC_PER_SEC / 25;
-static const int cfq_slice_async_rq = 2;
-static u64 cfq_slice_idle = NSEC_PER_SEC / 125;
-static u64 cfq_group_idle = NSEC_PER_SEC / 125;
-static const u64 cfq_target_latency = (u64)NSEC_PER_SEC * 3/10; /* 300 ms */
-static const int cfq_hist_divisor = 4;
-
-/*
- * offset from end of queue service tree for idle class
- */
-#define CFQ_IDLE_DELAY (NSEC_PER_SEC / 5)
-/* offset from end of group service tree under time slice mode */
-#define CFQ_SLICE_MODE_GROUP_DELAY (NSEC_PER_SEC / 5)
-/* offset from end of group service under IOPS mode */
-#define CFQ_IOPS_MODE_GROUP_DELAY (HZ / 5)
-
-/*
- * below this threshold, we consider thinktime immediate
- */
-#define CFQ_MIN_TT (2 * NSEC_PER_SEC / HZ)
-
-#define CFQ_SLICE_SCALE (5)
-#define CFQ_HW_QUEUE_MIN (5)
-#define CFQ_SERVICE_SHIFT 12
-
-#define CFQQ_SEEK_THR (sector_t)(8 * 100)
-#define CFQQ_CLOSE_THR (sector_t)(8 * 1024)
-#define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32)
-#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
-
-#define RQ_CIC(rq) icq_to_cic((rq)->elv.icq)
-#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0])
-#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1])
-
-static struct kmem_cache *cfq_pool;
-
-#define CFQ_PRIO_LISTS IOPRIO_BE_NR
-#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
-
-#define sample_valid(samples) ((samples) > 80)
-#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node)
-
-/* blkio-related constants */
-#define CFQ_WEIGHT_LEGACY_MIN 10
-#define CFQ_WEIGHT_LEGACY_DFL 500
-#define CFQ_WEIGHT_LEGACY_MAX 1000
-
-struct cfq_ttime {
- u64 last_end_request;
-
- u64 ttime_total;
- u64 ttime_mean;
- unsigned long ttime_samples;
-};
-
-/*
- * Most of our rbtree usage is for sorting with min extraction, so
- * if we cache the leftmost node we don't have to walk down the tree
- * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
- * move this into the elevator for the rq sorting as well.
- */
-struct cfq_rb_root {
- struct rb_root_cached rb;
- struct rb_node *rb_rightmost;
- unsigned count;
- u64 min_vdisktime;
- struct cfq_ttime ttime;
-};
-#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT_CACHED, \
- .rb_rightmost = NULL, \
- .ttime = {.last_end_request = ktime_get_ns(),},}
-
-/*
- * Per process-grouping structure
- */
-struct cfq_queue {
- /* reference count */
- int ref;
- /* various state flags, see below */
- unsigned int flags;
- /* parent cfq_data */
- struct cfq_data *cfqd;
- /* service_tree member */
- struct rb_node rb_node;
- /* service_tree key */
- u64 rb_key;
- /* prio tree member */
- struct rb_node p_node;
- /* prio tree root we belong to, if any */
- struct rb_root *p_root;
- /* sorted list of pending requests */
- struct rb_root sort_list;
- /* if fifo isn't expired, next request to serve */
- struct request *next_rq;
- /* requests queued in sort_list */
- int queued[2];
- /* currently allocated requests */
- int allocated[2];
- /* fifo list of requests in sort_list */
- struct list_head fifo;
-
- /* time when queue got scheduled in to dispatch first request. */
- u64 dispatch_start;
- u64 allocated_slice;
- u64 slice_dispatch;
- /* time when first request from queue completed and slice started. */
- u64 slice_start;
- u64 slice_end;
- s64 slice_resid;
-
- /* pending priority requests */
- int prio_pending;
- /* number of requests that are on the dispatch list or inside driver */
- int dispatched;
-
- /* io prio of this group */
- unsigned short ioprio, org_ioprio;
- unsigned short ioprio_class, org_ioprio_class;
-
- pid_t pid;
-
- u32 seek_history;
- sector_t last_request_pos;
-
- struct cfq_rb_root *service_tree;
- struct cfq_queue *new_cfqq;
- struct cfq_group *cfqg;
- /* Number of sectors dispatched from queue in single dispatch round */
- unsigned long nr_sectors;
-};
-
-/*
- * First index in the service_trees.
- * IDLE is handled separately, so it has negative index
- */
-enum wl_class_t {
- BE_WORKLOAD = 0,
- RT_WORKLOAD = 1,
- IDLE_WORKLOAD = 2,
- CFQ_PRIO_NR,
-};
-
-/*
- * Second index in the service_trees.
- */
-enum wl_type_t {
- ASYNC_WORKLOAD = 0,
- SYNC_NOIDLE_WORKLOAD = 1,
- SYNC_WORKLOAD = 2
-};
-
-struct cfqg_stats {
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- /* number of ios merged */
- struct blkg_rwstat merged;
- /* total time spent on device in ns, may not be accurate w/ queueing */
- struct blkg_rwstat service_time;
- /* total time spent waiting in scheduler queue in ns */
- struct blkg_rwstat wait_time;
- /* number of IOs queued up */
- struct blkg_rwstat queued;
- /* total disk time and nr sectors dispatched by this group */
- struct blkg_stat time;
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- /* time not charged to this cgroup */
- struct blkg_stat unaccounted_time;
- /* sum of number of ios queued across all samples */
- struct blkg_stat avg_queue_size_sum;
- /* count of samples taken for average */
- struct blkg_stat avg_queue_size_samples;
- /* how many times this group has been removed from service tree */
- struct blkg_stat dequeue;
- /* total time spent waiting for it to be assigned a timeslice. */
- struct blkg_stat group_wait_time;
- /* time spent idling for this blkcg_gq */
- struct blkg_stat idle_time;
- /* total time with empty current active q with other requests queued */
- struct blkg_stat empty_time;
- /* fields after this shouldn't be cleared on stat reset */
- u64 start_group_wait_time;
- u64 start_idle_time;
- u64 start_empty_time;
- uint16_t flags;
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
-#endif /* CONFIG_CFQ_GROUP_IOSCHED */
-};
-
-/* Per-cgroup data */
-struct cfq_group_data {
- /* must be the first member */
- struct blkcg_policy_data cpd;
-
- unsigned int weight;
- unsigned int leaf_weight;
-};
-
-/* This is per cgroup per device grouping structure */
-struct cfq_group {
- /* must be the first member */
- struct blkg_policy_data pd;
-
- /* group service_tree member */
- struct rb_node rb_node;
-
- /* group service_tree key */
- u64 vdisktime;
-
- /*
- * The number of active cfqgs and sum of their weights under this
- * cfqg. This covers this cfqg's leaf_weight and all children's
- * weights, but does not cover weights of further descendants.
- *
- * If a cfqg is on the service tree, it's active. An active cfqg
- * also activates its parent and contributes to the children_weight
- * of the parent.
- */
- int nr_active;
- unsigned int children_weight;
-
- /*
- * vfraction is the fraction of vdisktime that the tasks in this
- * cfqg are entitled to. This is determined by compounding the
- * ratios walking up from this cfqg to the root.
- *
- * It is in fixed point w/ CFQ_SERVICE_SHIFT and the sum of all
- * vfractions on a service tree is approximately 1. The sum may
- * deviate a bit due to rounding errors and fluctuations caused by
- * cfqgs entering and leaving the service tree.
- */
- unsigned int vfraction;
-
- /*
- * There are two weights - (internal) weight is the weight of this
- * cfqg against the sibling cfqgs. leaf_weight is the wight of
- * this cfqg against the child cfqgs. For the root cfqg, both
- * weights are kept in sync for backward compatibility.
- */
- unsigned int weight;
- unsigned int new_weight;
- unsigned int dev_weight;
-
- unsigned int leaf_weight;
- unsigned int new_leaf_weight;
- unsigned int dev_leaf_weight;
-
- /* number of cfqq currently on this group */
- int nr_cfqq;
-
- /*
- * Per group busy queues average. Useful for workload slice calc. We
- * create the array for each prio class but at run time it is used
- * only for RT and BE class and slot for IDLE class remains unused.
- * This is primarily done to avoid confusion and a gcc warning.
- */
- unsigned int busy_queues_avg[CFQ_PRIO_NR];
- /*
- * rr lists of queues with requests. We maintain service trees for
- * RT and BE classes. These trees are subdivided in subclasses
- * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
- * class there is no subclassification and all the cfq queues go on
- * a single tree service_tree_idle.
- * Counts are embedded in the cfq_rb_root
- */
- struct cfq_rb_root service_trees[2][3];
- struct cfq_rb_root service_tree_idle;
-
- u64 saved_wl_slice;
- enum wl_type_t saved_wl_type;
- enum wl_class_t saved_wl_class;
-
- /* number of requests that are on the dispatch list or inside driver */
- int dispatched;
- struct cfq_ttime ttime;
- struct cfqg_stats stats; /* stats for this cfqg */
-
- /* async queue for each priority case */
- struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
- struct cfq_queue *async_idle_cfqq;
-
-};
-
-struct cfq_io_cq {
- struct io_cq icq; /* must be the first member */
- struct cfq_queue *cfqq[2];
- struct cfq_ttime ttime;
- int ioprio; /* the current ioprio */
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- uint64_t blkcg_serial_nr; /* the current blkcg serial */
-#endif
-};
-
-/*
- * Per block device queue structure
- */
-struct cfq_data {
- struct request_queue *queue;
- /* Root service tree for cfq_groups */
- struct cfq_rb_root grp_service_tree;
- struct cfq_group *root_group;
-
- /*
- * The priority currently being served
- */
- enum wl_class_t serving_wl_class;
- enum wl_type_t serving_wl_type;
- u64 workload_expires;
- struct cfq_group *serving_group;
-
- /*
- * Each priority tree is sorted by next_request position. These
- * trees are used when determining if two or more queues are
- * interleaving requests (see cfq_close_cooperator).
- */
- struct rb_root prio_trees[CFQ_PRIO_LISTS];
-
- unsigned int busy_queues;
- unsigned int busy_sync_queues;
-
- int rq_in_driver;
- int rq_in_flight[2];
-
- /*
- * queue-depth detection
- */
- int rq_queued;
- int hw_tag;
- /*
- * hw_tag can be
- * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
- * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
- * 0 => no NCQ
- */
- int hw_tag_est_depth;
- unsigned int hw_tag_samples;
-
- /*
- * idle window management
- */
- struct hrtimer idle_slice_timer;
- struct work_struct unplug_work;
-
- struct cfq_queue *active_queue;
- struct cfq_io_cq *active_cic;
-
- sector_t last_position;
-
- /*
- * tunables, see top of file
- */
- unsigned int cfq_quantum;
- unsigned int cfq_back_penalty;
- unsigned int cfq_back_max;
- unsigned int cfq_slice_async_rq;
- unsigned int cfq_latency;
- u64 cfq_fifo_expire[2];
- u64 cfq_slice[2];
- u64 cfq_slice_idle;
- u64 cfq_group_idle;
- u64 cfq_target_latency;
-
- /*
- * Fallback dummy cfqq for extreme OOM conditions
- */
- struct cfq_queue oom_cfqq;
-
- u64 last_delayed_sync;
-};
-
-static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
-static void cfq_put_queue(struct cfq_queue *cfqq);
-
-static struct cfq_rb_root *st_for(struct cfq_group *cfqg,
- enum wl_class_t class,
- enum wl_type_t type)
-{
- if (!cfqg)
- return NULL;
-
- if (class == IDLE_WORKLOAD)
- return &cfqg->service_tree_idle;
-
- return &cfqg->service_trees[class][type];
-}
-
-enum cfqq_state_flags {
- CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */
- CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
- CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */
- CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
- CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
- CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */
- CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
- CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
- CFQ_CFQQ_FLAG_sync, /* synchronous queue */
- CFQ_CFQQ_FLAG_coop, /* cfqq is shared */
- CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */
- CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */
- CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */
-};
-
-#define CFQ_CFQQ_FNS(name) \
-static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
-{ \
- (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
-} \
-static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
-{ \
- (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
-} \
-static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
-{ \
- return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
-}
-
-CFQ_CFQQ_FNS(on_rr);
-CFQ_CFQQ_FNS(wait_request);
-CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(must_alloc_slice);
-CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
-CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(slice_new);
-CFQ_CFQQ_FNS(sync);
-CFQ_CFQQ_FNS(coop);
-CFQ_CFQQ_FNS(split_coop);
-CFQ_CFQQ_FNS(deep);
-CFQ_CFQQ_FNS(wait_busy);
-#undef CFQ_CFQQ_FNS
-
-#if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
-
-/* cfqg stats flags */
-enum cfqg_stats_flags {
- CFQG_stats_waiting = 0,
- CFQG_stats_idling,
- CFQG_stats_empty,
-};
-
-#define CFQG_FLAG_FNS(name) \
-static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \
-{ \
- stats->flags |= (1 << CFQG_stats_##name); \
-} \
-static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \
-{ \
- stats->flags &= ~(1 << CFQG_stats_##name); \
-} \
-static inline int cfqg_stats_##name(struct cfqg_stats *stats) \
-{ \
- return (stats->flags & (1 << CFQG_stats_##name)) != 0; \
-} \
-
-CFQG_FLAG_FNS(waiting)
-CFQG_FLAG_FNS(idling)
-CFQG_FLAG_FNS(empty)
-#undef CFQG_FLAG_FNS
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats)
-{
- u64 now;
-
- if (!cfqg_stats_waiting(stats))
- return;
-
- now = ktime_get_ns();
- if (now > stats->start_group_wait_time)
- blkg_stat_add(&stats->group_wait_time,
- now - stats->start_group_wait_time);
- cfqg_stats_clear_waiting(stats);
-}
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg,
- struct cfq_group *curr_cfqg)
-{
- struct cfqg_stats *stats = &cfqg->stats;
-
- if (cfqg_stats_waiting(stats))
- return;
- if (cfqg == curr_cfqg)
- return;
- stats->start_group_wait_time = ktime_get_ns();
- cfqg_stats_mark_waiting(stats);
-}
-
-/* This should be called with the queue_lock held. */
-static void cfqg_stats_end_empty_time(struct cfqg_stats *stats)
-{
- u64 now;
-
- if (!cfqg_stats_empty(stats))
- return;
-
- now = ktime_get_ns();
- if (now > stats->start_empty_time)
- blkg_stat_add(&stats->empty_time,
- now - stats->start_empty_time);
- cfqg_stats_clear_empty(stats);
-}
-
-static void cfqg_stats_update_dequeue(struct cfq_group *cfqg)
-{
- blkg_stat_add(&cfqg->stats.dequeue, 1);
-}
-
-static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg)
-{
- struct cfqg_stats *stats = &cfqg->stats;
-
- if (blkg_rwstat_total(&stats->queued))
- return;
-
- /*
- * group is already marked empty. This can happen if cfqq got new
- * request in parent group and moved to this group while being added
- * to service tree. Just ignore the event and move on.
- */
- if (cfqg_stats_empty(stats))
- return;
-
- stats->start_empty_time = ktime_get_ns();
- cfqg_stats_mark_empty(stats);
-}
-
-static void cfqg_stats_update_idle_time(struct cfq_group *cfqg)
-{
- struct cfqg_stats *stats = &cfqg->stats;
-
- if (cfqg_stats_idling(stats)) {
- u64 now = ktime_get_ns();
-
- if (now > stats->start_idle_time)
- blkg_stat_add(&stats->idle_time,
- now - stats->start_idle_time);
- cfqg_stats_clear_idling(stats);
- }
-}
-
-static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg)
-{
- struct cfqg_stats *stats = &cfqg->stats;
-
- BUG_ON(cfqg_stats_idling(stats));
-
- stats->start_idle_time = ktime_get_ns();
- cfqg_stats_mark_idling(stats);
-}
-
-static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg)
-{
- struct cfqg_stats *stats = &cfqg->stats;
-
- blkg_stat_add(&stats->avg_queue_size_sum,
- blkg_rwstat_total(&stats->queued));
- blkg_stat_add(&stats->avg_queue_size_samples, 1);
- cfqg_stats_update_group_wait_time(stats);
-}
-
-#else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
-
-static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { }
-static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { }
-static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { }
-static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { }
-
-#endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-
-static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
-{
- return pd ? container_of(pd, struct cfq_group, pd) : NULL;
-}
-
-static struct cfq_group_data
-*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
-{
- return cpd ? container_of(cpd, struct cfq_group_data, cpd) : NULL;
-}
-
-static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
-{
- return pd_to_blkg(&cfqg->pd);
-}
-
-static struct blkcg_policy blkcg_policy_cfq;
-
-static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg)
-{
- return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq));
-}
-
-static struct cfq_group_data *blkcg_to_cfqgd(struct blkcg *blkcg)
-{
- return cpd_to_cfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_cfq));
-}
-
-static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg)
-{
- struct blkcg_gq *pblkg = cfqg_to_blkg(cfqg)->parent;
-
- return pblkg ? blkg_to_cfqg(pblkg) : NULL;
-}
-
-static inline bool cfqg_is_descendant(struct cfq_group *cfqg,
- struct cfq_group *ancestor)
-{
- return cgroup_is_descendant(cfqg_to_blkg(cfqg)->blkcg->css.cgroup,
- cfqg_to_blkg(ancestor)->blkcg->css.cgroup);
-}
-
-static inline void cfqg_get(struct cfq_group *cfqg)
-{
- return blkg_get(cfqg_to_blkg(cfqg));
-}
-
-static inline void cfqg_put(struct cfq_group *cfqg)
-{
- return blkg_put(cfqg_to_blkg(cfqg));
-}
-
-#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
- blk_add_cgroup_trace_msg((cfqd)->queue, \
- cfqg_to_blkg((cfqq)->cfqg)->blkcg, \
- "cfq%d%c%c " fmt, (cfqq)->pid, \
- cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
- cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
- ##args); \
-} while (0)
-
-#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
- blk_add_cgroup_trace_msg((cfqd)->queue, \
- cfqg_to_blkg(cfqg)->blkcg, fmt, ##args); \
-} while (0)
-
-static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
- struct cfq_group *curr_cfqg,
- unsigned int op)
-{
- blkg_rwstat_add(&cfqg->stats.queued, op, 1);
- cfqg_stats_end_empty_time(&cfqg->stats);
- cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg);
-}
-
-static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
- uint64_t time, unsigned long unaccounted_time)
-{
- blkg_stat_add(&cfqg->stats.time, time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time);
-#endif
-}
-
-static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg,
- unsigned int op)
-{
- blkg_rwstat_add(&cfqg->stats.queued, op, -1);
-}
-
-static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg,
- unsigned int op)
-{
- blkg_rwstat_add(&cfqg->stats.merged, op, 1);
-}
-
-static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
- u64 start_time_ns,
- u64 io_start_time_ns,
- unsigned int op)
-{
- struct cfqg_stats *stats = &cfqg->stats;
- u64 now = ktime_get_ns();
-
- if (now > io_start_time_ns)
- blkg_rwstat_add(&stats->service_time, op,
- now - io_start_time_ns);
- if (io_start_time_ns > start_time_ns)
- blkg_rwstat_add(&stats->wait_time, op,
- io_start_time_ns - start_time_ns);
-}
-
-/* @stats = 0 */
-static void cfqg_stats_reset(struct cfqg_stats *stats)
-{
- /* queued stats shouldn't be cleared */
- blkg_rwstat_reset(&stats->merged);
- blkg_rwstat_reset(&stats->service_time);
- blkg_rwstat_reset(&stats->wait_time);
- blkg_stat_reset(&stats->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- blkg_stat_reset(&stats->unaccounted_time);
- blkg_stat_reset(&stats->avg_queue_size_sum);
- blkg_stat_reset(&stats->avg_queue_size_samples);
- blkg_stat_reset(&stats->dequeue);
- blkg_stat_reset(&stats->group_wait_time);
- blkg_stat_reset(&stats->idle_time);
- blkg_stat_reset(&stats->empty_time);
-#endif
-}
-
-/* @to += @from */
-static void cfqg_stats_add_aux(struct cfqg_stats *to, struct cfqg_stats *from)
-{
- /* queued stats shouldn't be cleared */
- blkg_rwstat_add_aux(&to->merged, &from->merged);
- blkg_rwstat_add_aux(&to->service_time, &from->service_time);
- blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
- blkg_stat_add_aux(&from->time, &from->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- blkg_stat_add_aux(&to->unaccounted_time, &from->unaccounted_time);
- blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
- blkg_stat_add_aux(&to->avg_queue_size_samples, &from->avg_queue_size_samples);
- blkg_stat_add_aux(&to->dequeue, &from->dequeue);
- blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
- blkg_stat_add_aux(&to->idle_time, &from->idle_time);
- blkg_stat_add_aux(&to->empty_time, &from->empty_time);
-#endif
-}
-
-/*
- * Transfer @cfqg's stats to its parent's aux counts so that the ancestors'
- * recursive stats can still account for the amount used by this cfqg after
- * it's gone.
- */
-static void cfqg_stats_xfer_dead(struct cfq_group *cfqg)
-{
- struct cfq_group *parent = cfqg_parent(cfqg);
-
- lockdep_assert_held(cfqg_to_blkg(cfqg)->q->queue_lock);
-
- if (unlikely(!parent))
- return;
-
- cfqg_stats_add_aux(&parent->stats, &cfqg->stats);
- cfqg_stats_reset(&cfqg->stats);
-}
-
-#else /* CONFIG_CFQ_GROUP_IOSCHED */
-
-static inline struct cfq_group *cfqg_parent(struct cfq_group *cfqg) { return NULL; }
-static inline bool cfqg_is_descendant(struct cfq_group *cfqg,
- struct cfq_group *ancestor)
-{
- return true;
-}
-static inline void cfqg_get(struct cfq_group *cfqg) { }
-static inline void cfqg_put(struct cfq_group *cfqg) { }
-
-#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
- blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c " fmt, (cfqq)->pid, \
- cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
- cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
- ##args)
-#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
-
-static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
- struct cfq_group *curr_cfqg, unsigned int op) { }
-static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
- uint64_t time, unsigned long unaccounted_time) { }
-static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg,
- unsigned int op) { }
-static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg,
- unsigned int op) { }
-static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
- u64 start_time_ns,
- u64 io_start_time_ns,
- unsigned int op) { }
-
-#endif /* CONFIG_CFQ_GROUP_IOSCHED */
-
-#define cfq_log(cfqd, fmt, args...) \
- blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
-
-/* Traverses through cfq group service trees */
-#define for_each_cfqg_st(cfqg, i, j, st) \
- for (i = 0; i <= IDLE_WORKLOAD; i++) \
- for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
- : &cfqg->service_tree_idle; \
- (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
- (i == IDLE_WORKLOAD && j == 0); \
- j++, st = i < IDLE_WORKLOAD ? \
- &cfqg->service_trees[i][j]: NULL) \
-
-static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
- struct cfq_ttime *ttime, bool group_idle)
-{
- u64 slice;
- if (!sample_valid(ttime->ttime_samples))
- return false;
- if (group_idle)
- slice = cfqd->cfq_group_idle;
- else
- slice = cfqd->cfq_slice_idle;
- return ttime->ttime_mean > slice;
-}
-
-static inline bool iops_mode(struct cfq_data *cfqd)
-{
- /*
- * If we are not idling on queues and it is a NCQ drive, parallel
- * execution of requests is on and measuring time is not possible
- * in most of the cases until and unless we drive shallower queue
- * depths and that becomes a performance bottleneck. In such cases
- * switch to start providing fairness in terms of number of IOs.
- */
- if (!cfqd->cfq_slice_idle && cfqd->hw_tag)
- return true;
- else
- return false;
-}
-
-static inline enum wl_class_t cfqq_class(struct cfq_queue *cfqq)
-{
- if (cfq_class_idle(cfqq))
- return IDLE_WORKLOAD;
- if (cfq_class_rt(cfqq))
- return RT_WORKLOAD;
- return BE_WORKLOAD;
-}
-
-
-static enum wl_type_t cfqq_type(struct cfq_queue *cfqq)
-{
- if (!cfq_cfqq_sync(cfqq))
- return ASYNC_WORKLOAD;
- if (!cfq_cfqq_idle_window(cfqq))
- return SYNC_NOIDLE_WORKLOAD;
- return SYNC_WORKLOAD;
-}
-
-static inline int cfq_group_busy_queues_wl(enum wl_class_t wl_class,
- struct cfq_data *cfqd,
- struct cfq_group *cfqg)
-{
- if (wl_class == IDLE_WORKLOAD)
- return cfqg->service_tree_idle.count;
-
- return cfqg->service_trees[wl_class][ASYNC_WORKLOAD].count +
- cfqg->service_trees[wl_class][SYNC_NOIDLE_WORKLOAD].count +
- cfqg->service_trees[wl_class][SYNC_WORKLOAD].count;
-}
-
-static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
- struct cfq_group *cfqg)
-{
- return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count +
- cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count;
-}
-
-static void cfq_dispatch_insert(struct request_queue *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync,
- struct cfq_io_cq *cic, struct bio *bio);
-
-static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
-{
- /* cic->icq is the first member, %NULL will convert to %NULL */
- return container_of(icq, struct cfq_io_cq, icq);
-}
-
-static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd,
- struct io_context *ioc)
-{
- if (ioc)
- return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue));
- return NULL;
-}
-
-static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync)
-{
- return cic->cfqq[is_sync];
-}
-
-static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
- bool is_sync)
-{
- cic->cfqq[is_sync] = cfqq;
-}
-
-static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic)
-{
- return cic->icq.q->elevator->elevator_data;
-}
-
-/*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
- */
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
-{
- if (cfqd->busy_queues) {
- cfq_log(cfqd, "schedule dispatch");
- kblockd_schedule_work(&cfqd->unplug_work);
- }
-}
-
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline u64 cfq_prio_slice(struct cfq_data *cfqd, bool sync,
- unsigned short prio)
-{
- u64 base_slice = cfqd->cfq_slice[sync];
- u64 slice = div_u64(base_slice, CFQ_SLICE_SCALE);
-
- WARN_ON(prio >= IOPRIO_BE_NR);
-
- return base_slice + (slice * (4 - prio));
-}
-
-static inline u64
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
-}
-
-/**
- * cfqg_scale_charge - scale disk time charge according to cfqg weight
- * @charge: disk time being charged
- * @vfraction: vfraction of the cfqg, fixed point w/ CFQ_SERVICE_SHIFT
- *
- * Scale @charge according to @vfraction, which is in range (0, 1]. The
- * scaling is inversely proportional.
- *
- * scaled = charge / vfraction
- *
- * The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
- */
-static inline u64 cfqg_scale_charge(u64 charge,
- unsigned int vfraction)
-{
- u64 c = charge << CFQ_SERVICE_SHIFT; /* make it fixed point */
-
- /* charge / vfraction */
- c <<= CFQ_SERVICE_SHIFT;
- return div_u64(c, vfraction);
-}
-
-static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
-{
- s64 delta = (s64)(vdisktime - min_vdisktime);
- if (delta > 0)
- min_vdisktime = vdisktime;
-
- return min_vdisktime;
-}
-
-static void update_min_vdisktime(struct cfq_rb_root *st)
-{
- if (!RB_EMPTY_ROOT(&st->rb.rb_root)) {
- struct cfq_group *cfqg = rb_entry_cfqg(st->rb.rb_leftmost);
-
- st->min_vdisktime = max_vdisktime(st->min_vdisktime,
- cfqg->vdisktime);
- }
-}
-
-/*
- * get averaged number of queues of RT/BE priority.
- * average is updated, with a formula that gives more weight to higher numbers,
- * to quickly follows sudden increases and decrease slowly
- */
-
-static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
- struct cfq_group *cfqg, bool rt)
-{
- unsigned min_q, max_q;
- unsigned mult = cfq_hist_divisor - 1;
- unsigned round = cfq_hist_divisor / 2;
- unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg);
-
- min_q = min(cfqg->busy_queues_avg[rt], busy);
- max_q = max(cfqg->busy_queues_avg[rt], busy);
- cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) /
- cfq_hist_divisor;
- return cfqg->busy_queues_avg[rt];
-}
-
-static inline u64
-cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
- return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT;
-}
-
-static inline u64
-cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- u64 slice = cfq_prio_to_slice(cfqd, cfqq);
- if (cfqd->cfq_latency) {
- /*
- * interested queues (we consider only the ones with the same
- * priority class in the cfq group)
- */
- unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg,
- cfq_class_rt(cfqq));
- u64 sync_slice = cfqd->cfq_slice[1];
- u64 expect_latency = sync_slice * iq;
- u64 group_slice = cfq_group_slice(cfqd, cfqq->cfqg);
-
- if (expect_latency > group_slice) {
- u64 base_low_slice = 2 * cfqd->cfq_slice_idle;
- u64 low_slice;
-
- /* scale low_slice according to IO priority
- * and sync vs async */
- low_slice = div64_u64(base_low_slice*slice, sync_slice);
- low_slice = min(slice, low_slice);
- /* the adapted slice value is scaled to fit all iqs
- * into the target latency */
- slice = div64_u64(slice*group_slice, expect_latency);
- slice = max(slice, low_slice);
- }
- }
- return slice;
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- u64 slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
- u64 now = ktime_get_ns();
-
- cfqq->slice_start = now;
- cfqq->slice_end = now + slice;
- cfqq->allocated_slice = slice;
- cfq_log_cfqq(cfqd, cfqq, "set_slice=%llu", cfqq->slice_end - now);
-}
-
-/*
- * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
- * isn't valid until the first request from the dispatch is activated
- * and the slice time set.
- */
-static inline bool cfq_slice_used(struct cfq_queue *cfqq)
-{
- if (cfq_cfqq_slice_new(cfqq))
- return false;
- if (ktime_get_ns() < cfqq->slice_end)
- return false;
-
- return true;
-}
-
-/*
- * Lifted from AS - choose which of rq1 and rq2 that is best served now.
- * We choose the request that is closest to the head right now. Distance
- * behind the head is penalized and only allowed to a certain extent.
- */
-static struct request *
-cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last)
-{
- sector_t s1, s2, d1 = 0, d2 = 0;
- unsigned long back_max;
-#define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
-#define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
- unsigned wrap = 0; /* bit mask: requests behind the disk head? */
-
- if (rq1 == NULL || rq1 == rq2)
- return rq2;
- if (rq2 == NULL)
- return rq1;
-
- if (rq_is_sync(rq1) != rq_is_sync(rq2))
- return rq_is_sync(rq1) ? rq1 : rq2;
-
- if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO)
- return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2;
-
- s1 = blk_rq_pos(rq1);
- s2 = blk_rq_pos(rq2);
-
- /*
- * by definition, 1KiB is 2 sectors
- */
- back_max = cfqd->cfq_back_max * 2;
-
- /*
- * Strict one way elevator _except_ in the case where we allow
- * short backward seeks which are biased as twice the cost of a
- * similar forward seek.
- */
- if (s1 >= last)
- d1 = s1 - last;
- else if (s1 + back_max >= last)
- d1 = (last - s1) * cfqd->cfq_back_penalty;
- else
- wrap |= CFQ_RQ1_WRAP;
-
- if (s2 >= last)
- d2 = s2 - last;
- else if (s2 + back_max >= last)
- d2 = (last - s2) * cfqd->cfq_back_penalty;
- else
- wrap |= CFQ_RQ2_WRAP;
-
- /* Found required data */
-
- /*
- * By doing switch() on the bit mask "wrap" we avoid having to
- * check two variables for all permutations: --> faster!
- */
- switch (wrap) {
- case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
- if (d1 < d2)
- return rq1;
- else if (d2 < d1)
- return rq2;
- else {
- if (s1 >= s2)
- return rq1;
- else
- return rq2;
- }
-
- case CFQ_RQ2_WRAP:
- return rq1;
- case CFQ_RQ1_WRAP:
- return rq2;
- case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
- default:
- /*
- * Since both rqs are wrapped,
- * start with the one that's further behind head
- * (--> only *one* back seek required),
- * since back seek takes more time than forward.
- */
- if (s1 <= s2)
- return rq1;
- else
- return rq2;
- }
-}
-
-static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
-{
- /* Service tree is empty */
- if (!root->count)
- return NULL;
-
- return rb_entry(rb_first_cached(&root->rb), struct cfq_queue, rb_node);
-}
-
-static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root)
-{
- return rb_entry_cfqg(rb_first_cached(&root->rb));
-}
-
-static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
-{
- if (root->rb_rightmost == n)
- root->rb_rightmost = rb_prev(n);
-
- rb_erase_cached(n, &root->rb);
- RB_CLEAR_NODE(n);
-
- --root->count;
-}
-
-/*
- * would be nice to take fifo expire time into account as well
- */
-static struct request *
-cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *last)
-{
- struct rb_node *rbnext = rb_next(&last->rb_node);
- struct rb_node *rbprev = rb_prev(&last->rb_node);
- struct request *next = NULL, *prev = NULL;
-
- BUG_ON(RB_EMPTY_NODE(&last->rb_node));
-
- if (rbprev)
- prev = rb_entry_rq(rbprev);
-
- if (rbnext)
- next = rb_entry_rq(rbnext);
- else {
- rbnext = rb_first(&cfqq->sort_list);
- if (rbnext && rbnext != &last->rb_node)
- next = rb_entry_rq(rbnext);
- }
-
- return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last));
-}
-
-static u64 cfq_slice_offset(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- /*
- * just an approximation, should be ok.
- */
- return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) -
- cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
-}
-
-static inline s64
-cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
- return cfqg->vdisktime - st->min_vdisktime;
-}
-
-static void
-__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
- struct rb_node **node = &st->rb.rb_root.rb_node;
- struct rb_node *parent = NULL;
- struct cfq_group *__cfqg;
- s64 key = cfqg_key(st, cfqg);
- bool leftmost = true, rightmost = true;
-
- while (*node != NULL) {
- parent = *node;
- __cfqg = rb_entry_cfqg(parent);
-
- if (key < cfqg_key(st, __cfqg)) {
- node = &parent->rb_left;
- rightmost = false;
- } else {
- node = &parent->rb_right;
- leftmost = false;
- }
- }
-
- if (rightmost)
- st->rb_rightmost = &cfqg->rb_node;
-
- rb_link_node(&cfqg->rb_node, parent, node);
- rb_insert_color_cached(&cfqg->rb_node, &st->rb, leftmost);
-}
-
-/*
- * This has to be called only on activation of cfqg
- */
-static void
-cfq_update_group_weight(struct cfq_group *cfqg)
-{
- if (cfqg->new_weight) {
- cfqg->weight = cfqg->new_weight;
- cfqg->new_weight = 0;
- }
-}
-
-static void
-cfq_update_group_leaf_weight(struct cfq_group *cfqg)
-{
- BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
-
- if (cfqg->new_leaf_weight) {
- cfqg->leaf_weight = cfqg->new_leaf_weight;
- cfqg->new_leaf_weight = 0;
- }
-}
-
-static void
-cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
- unsigned int vfr = 1 << CFQ_SERVICE_SHIFT; /* start with 1 */
- struct cfq_group *pos = cfqg;
- struct cfq_group *parent;
- bool propagate;
-
- /* add to the service tree */
- BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
-
- /*
- * Update leaf_weight. We cannot update weight at this point
- * because cfqg might already have been activated and is
- * contributing its current weight to the parent's child_weight.
- */
- cfq_update_group_leaf_weight(cfqg);
- __cfq_group_service_tree_add(st, cfqg);
-
- /*
- * Activate @cfqg and calculate the portion of vfraction @cfqg is
- * entitled to. vfraction is calculated by walking the tree
- * towards the root calculating the fraction it has at each level.
- * The compounded ratio is how much vfraction @cfqg owns.
- *
- * Start with the proportion tasks in this cfqg has against active
- * children cfqgs - its leaf_weight against children_weight.
- */
- propagate = !pos->nr_active++;
- pos->children_weight += pos->leaf_weight;
- vfr = vfr * pos->leaf_weight / pos->children_weight;
-
- /*
- * Compound ->weight walking up the tree. Both activation and
- * vfraction calculation are done in the same loop. Propagation
- * stops once an already activated node is met. vfraction
- * calculation should always continue to the root.
- */
- while ((parent = cfqg_parent(pos))) {
- if (propagate) {
- cfq_update_group_weight(pos);
- propagate = !parent->nr_active++;
- parent->children_weight += pos->weight;
- }
- vfr = vfr * pos->weight / parent->children_weight;
- pos = parent;
- }
-
- cfqg->vfraction = max_t(unsigned, vfr, 1);
-}
-
-static inline u64 cfq_get_cfqg_vdisktime_delay(struct cfq_data *cfqd)
-{
- if (!iops_mode(cfqd))
- return CFQ_SLICE_MODE_GROUP_DELAY;
- else
- return CFQ_IOPS_MODE_GROUP_DELAY;
-}
-
-static void
-cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
- struct cfq_rb_root *st = &cfqd->grp_service_tree;
- struct cfq_group *__cfqg;
- struct rb_node *n;
-
- cfqg->nr_cfqq++;
- if (!RB_EMPTY_NODE(&cfqg->rb_node))
- return;
-
- /*
- * Currently put the group at the end. Later implement something
- * so that groups get lesser vtime based on their weights, so that
- * if group does not loose all if it was not continuously backlogged.
- */
- n = st->rb_rightmost;
- if (n) {
- __cfqg = rb_entry_cfqg(n);
- cfqg->vdisktime = __cfqg->vdisktime +
- cfq_get_cfqg_vdisktime_delay(cfqd);
- } else
- cfqg->vdisktime = st->min_vdisktime;
- cfq_group_service_tree_add(st, cfqg);
-}
-
-static void
-cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg)
-{
- struct cfq_group *pos = cfqg;
- bool propagate;
-
- /*
- * Undo activation from cfq_group_service_tree_add(). Deactivate
- * @cfqg and propagate deactivation upwards.
- */
- propagate = !--pos->nr_active;
- pos->children_weight -= pos->leaf_weight;
-
- while (propagate) {
- struct cfq_group *parent = cfqg_parent(pos);
-
- /* @pos has 0 nr_active at this point */
- WARN_ON_ONCE(pos->children_weight);
- pos->vfraction = 0;
-
- if (!parent)
- break;
-
- propagate = !--parent->nr_active;
- parent->children_weight -= pos->weight;
- pos = parent;
- }
-
- /* remove from the service tree */
- if (!RB_EMPTY_NODE(&cfqg->rb_node))
- cfq_rb_erase(&cfqg->rb_node, st);
-}
-
-static void
-cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
- struct cfq_rb_root *st = &cfqd->grp_service_tree;
-
- BUG_ON(cfqg->nr_cfqq < 1);
- cfqg->nr_cfqq--;
-
- /* If there are other cfq queues under this group, don't delete it */
- if (cfqg->nr_cfqq)
- return;
-
- cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
- cfq_group_service_tree_del(st, cfqg);
- cfqg->saved_wl_slice = 0;
- cfqg_stats_update_dequeue(cfqg);
-}
-
-static inline u64 cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
- u64 *unaccounted_time)
-{
- u64 slice_used;
- u64 now = ktime_get_ns();
-
- /*
- * Queue got expired before even a single request completed or
- * got expired immediately after first request completion.
- */
- if (!cfqq->slice_start || cfqq->slice_start == now) {
- /*
- * Also charge the seek time incurred to the group, otherwise
- * if there are mutiple queues in the group, each can dispatch
- * a single request on seeky media and cause lots of seek time
- * and group will never know it.
- */
- slice_used = max_t(u64, (now - cfqq->dispatch_start),
- jiffies_to_nsecs(1));
- } else {
- slice_used = now - cfqq->slice_start;
- if (slice_used > cfqq->allocated_slice) {
- *unaccounted_time = slice_used - cfqq->allocated_slice;
- slice_used = cfqq->allocated_slice;
- }
- if (cfqq->slice_start > cfqq->dispatch_start)
- *unaccounted_time += cfqq->slice_start -
- cfqq->dispatch_start;
- }
-
- return slice_used;
-}
-
-static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
- struct cfq_queue *cfqq)
-{
- struct cfq_rb_root *st = &cfqd->grp_service_tree;
- u64 used_sl, charge, unaccounted_sl = 0;
- int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
- - cfqg->service_tree_idle.count;
- unsigned int vfr;
- u64 now = ktime_get_ns();
-
- BUG_ON(nr_sync < 0);
- used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl);
-
- if (iops_mode(cfqd))
- charge = cfqq->slice_dispatch;
- else if (!cfq_cfqq_sync(cfqq) && !nr_sync)
- charge = cfqq->allocated_slice;
-
- /*
- * Can't update vdisktime while on service tree and cfqg->vfraction
- * is valid only while on it. Cache vfr, leave the service tree,
- * update vdisktime and go back on. The re-addition to the tree
- * will also update the weights as necessary.
- */
- vfr = cfqg->vfraction;
- cfq_group_service_tree_del(st, cfqg);
- cfqg->vdisktime += cfqg_scale_charge(charge, vfr);
- cfq_group_service_tree_add(st, cfqg);
-
- /* This group is being expired. Save the context */
- if (cfqd->workload_expires > now) {
- cfqg->saved_wl_slice = cfqd->workload_expires - now;
- cfqg->saved_wl_type = cfqd->serving_wl_type;
- cfqg->saved_wl_class = cfqd->serving_wl_class;
- } else
- cfqg->saved_wl_slice = 0;
-
- cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
- st->min_vdisktime);
- cfq_log_cfqq(cfqq->cfqd, cfqq,
- "sl_used=%llu disp=%llu charge=%llu iops=%u sect=%lu",
- used_sl, cfqq->slice_dispatch, charge,
- iops_mode(cfqd), cfqq->nr_sectors);
- cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl);
- cfqg_stats_set_start_empty_time(cfqg);
-}
-
-/**
- * cfq_init_cfqg_base - initialize base part of a cfq_group
- * @cfqg: cfq_group to initialize
- *
- * Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
- * is enabled or not.
- */
-static void cfq_init_cfqg_base(struct cfq_group *cfqg)
-{
- struct cfq_rb_root *st;
- int i, j;
-
- for_each_cfqg_st(cfqg, i, j, st)
- *st = CFQ_RB_ROOT;
- RB_CLEAR_NODE(&cfqg->rb_node);
-
- cfqg->ttime.last_end_request = ktime_get_ns();
-}
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
- bool on_dfl, bool reset_dev, bool is_leaf_weight);
-
-static void cfqg_stats_exit(struct cfqg_stats *stats)
-{
- blkg_rwstat_exit(&stats->merged);
- blkg_rwstat_exit(&stats->service_time);
- blkg_rwstat_exit(&stats->wait_time);
- blkg_rwstat_exit(&stats->queued);
- blkg_stat_exit(&stats->time);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- blkg_stat_exit(&stats->unaccounted_time);
- blkg_stat_exit(&stats->avg_queue_size_sum);
- blkg_stat_exit(&stats->avg_queue_size_samples);
- blkg_stat_exit(&stats->dequeue);
- blkg_stat_exit(&stats->group_wait_time);
- blkg_stat_exit(&stats->idle_time);
- blkg_stat_exit(&stats->empty_time);
-#endif
-}
-
-static int cfqg_stats_init(struct cfqg_stats *stats, gfp_t gfp)
-{
- if (blkg_rwstat_init(&stats->merged, gfp) ||
- blkg_rwstat_init(&stats->service_time, gfp) ||
- blkg_rwstat_init(&stats->wait_time, gfp) ||
- blkg_rwstat_init(&stats->queued, gfp) ||
- blkg_stat_init(&stats->time, gfp))
- goto err;
-
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- if (blkg_stat_init(&stats->unaccounted_time, gfp) ||
- blkg_stat_init(&stats->avg_queue_size_sum, gfp) ||
- blkg_stat_init(&stats->avg_queue_size_samples, gfp) ||
- blkg_stat_init(&stats->dequeue, gfp) ||
- blkg_stat_init(&stats->group_wait_time, gfp) ||
- blkg_stat_init(&stats->idle_time, gfp) ||
- blkg_stat_init(&stats->empty_time, gfp))
- goto err;
-#endif
- return 0;
-err:
- cfqg_stats_exit(stats);
- return -ENOMEM;
-}
-
-static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp)
-{
- struct cfq_group_data *cgd;
-
- cgd = kzalloc(sizeof(*cgd), gfp);
- if (!cgd)
- return NULL;
- return &cgd->cpd;
-}
-
-static void cfq_cpd_init(struct blkcg_policy_data *cpd)
-{
- struct cfq_group_data *cgd = cpd_to_cfqgd(cpd);
- unsigned int weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
- CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
-
- if (cpd_to_blkcg(cpd) == &blkcg_root)
- weight *= 2;
-
- cgd->weight = weight;
- cgd->leaf_weight = weight;
-}
-
-static void cfq_cpd_free(struct blkcg_policy_data *cpd)
-{
- kfree(cpd_to_cfqgd(cpd));
-}
-
-static void cfq_cpd_bind(struct blkcg_policy_data *cpd)
-{
- struct blkcg *blkcg = cpd_to_blkcg(cpd);
- bool on_dfl = cgroup_subsys_on_dfl(io_cgrp_subsys);
- unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
-
- if (blkcg == &blkcg_root)
- weight *= 2;
-
- WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, false));
- WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, true));
-}
-
-static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node)
-{
- struct cfq_group *cfqg;
-
- cfqg = kzalloc_node(sizeof(*cfqg), gfp, node);
- if (!cfqg)
- return NULL;
-
- cfq_init_cfqg_base(cfqg);
- if (cfqg_stats_init(&cfqg->stats, gfp)) {
- kfree(cfqg);
- return NULL;
- }
-
- return &cfqg->pd;
-}
-
-static void cfq_pd_init(struct blkg_policy_data *pd)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
- struct cfq_group_data *cgd = blkcg_to_cfqgd(pd->blkg->blkcg);
-
- cfqg->weight = cgd->weight;
- cfqg->leaf_weight = cgd->leaf_weight;
-}
-
-static void cfq_pd_offline(struct blkg_policy_data *pd)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
- int i;
-
- for (i = 0; i < IOPRIO_BE_NR; i++) {
- if (cfqg->async_cfqq[0][i]) {
- cfq_put_queue(cfqg->async_cfqq[0][i]);
- cfqg->async_cfqq[0][i] = NULL;
- }
- if (cfqg->async_cfqq[1][i]) {
- cfq_put_queue(cfqg->async_cfqq[1][i]);
- cfqg->async_cfqq[1][i] = NULL;
- }
- }
-
- if (cfqg->async_idle_cfqq) {
- cfq_put_queue(cfqg->async_idle_cfqq);
- cfqg->async_idle_cfqq = NULL;
- }
-
- /*
- * @blkg is going offline and will be ignored by
- * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
- * that they don't get lost. If IOs complete after this point, the
- * stats for them will be lost. Oh well...
- */
- cfqg_stats_xfer_dead(cfqg);
-}
-
-static void cfq_pd_free(struct blkg_policy_data *pd)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
-
- cfqg_stats_exit(&cfqg->stats);
- return kfree(cfqg);
-}
-
-static void cfq_pd_reset_stats(struct blkg_policy_data *pd)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
-
- cfqg_stats_reset(&cfqg->stats);
-}
-
-static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
- struct blkcg *blkcg)
-{
- struct blkcg_gq *blkg;
-
- blkg = blkg_lookup(blkcg, cfqd->queue);
- if (likely(blkg))
- return blkg_to_cfqg(blkg);
- return NULL;
-}
-
-static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
-{
- cfqq->cfqg = cfqg;
- /* cfqq reference on cfqg */
- cfqg_get(cfqg);
-}
-
-static u64 cfqg_prfill_weight_device(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
-
- if (!cfqg->dev_weight)
- return 0;
- return __blkg_prfill_u64(sf, pd, cfqg->dev_weight);
-}
-
-static int cfqg_print_weight_device(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_weight_device, &blkcg_policy_cfq,
- 0, false);
- return 0;
-}
-
-static u64 cfqg_prfill_leaf_weight_device(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
-
- if (!cfqg->dev_leaf_weight)
- return 0;
- return __blkg_prfill_u64(sf, pd, cfqg->dev_leaf_weight);
-}
-
-static int cfqg_print_leaf_weight_device(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_leaf_weight_device, &blkcg_policy_cfq,
- 0, false);
- return 0;
-}
-
-static int cfq_print_weight(struct seq_file *sf, void *v)
-{
- struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
- struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
- unsigned int val = 0;
-
- if (cgd)
- val = cgd->weight;
-
- seq_printf(sf, "%u\n", val);
- return 0;
-}
-
-static int cfq_print_leaf_weight(struct seq_file *sf, void *v)
-{
- struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
- struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
- unsigned int val = 0;
-
- if (cgd)
- val = cgd->leaf_weight;
-
- seq_printf(sf, "%u\n", val);
- return 0;
-}
-
-static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off,
- bool on_dfl, bool is_leaf_weight)
-{
- unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
- unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
- struct blkcg *blkcg = css_to_blkcg(of_css(of));
- struct blkg_conf_ctx ctx;
- struct cfq_group *cfqg;
- struct cfq_group_data *cfqgd;
- int ret;
- u64 v;
-
- ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx);
- if (ret)
- return ret;
-
- if (sscanf(ctx.body, "%llu", &v) == 1) {
- /* require "default" on dfl */
- ret = -ERANGE;
- if (!v && on_dfl)
- goto out_finish;
- } else if (!strcmp(strim(ctx.body), "default")) {
- v = 0;
- } else {
- ret = -EINVAL;
- goto out_finish;
- }
-
- cfqg = blkg_to_cfqg(ctx.blkg);
- cfqgd = blkcg_to_cfqgd(blkcg);
-
- ret = -ERANGE;
- if (!v || (v >= min && v <= max)) {
- if (!is_leaf_weight) {
- cfqg->dev_weight = v;
- cfqg->new_weight = v ?: cfqgd->weight;
- } else {
- cfqg->dev_leaf_weight = v;
- cfqg->new_leaf_weight = v ?: cfqgd->leaf_weight;
- }
- ret = 0;
- }
-out_finish:
- blkg_conf_finish(&ctx);
- return ret ?: nbytes;
-}
-
-static ssize_t cfqg_set_weight_device(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
-{
- return __cfqg_set_weight_device(of, buf, nbytes, off, false, false);
-}
-
-static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
-{
- return __cfqg_set_weight_device(of, buf, nbytes, off, false, true);
-}
-
-static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
- bool on_dfl, bool reset_dev, bool is_leaf_weight)
-{
- unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
- unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
- struct blkcg *blkcg = css_to_blkcg(css);
- struct blkcg_gq *blkg;
- struct cfq_group_data *cfqgd;
- int ret = 0;
-
- if (val < min || val > max)
- return -ERANGE;
-
- spin_lock_irq(&blkcg->lock);
- cfqgd = blkcg_to_cfqgd(blkcg);
- if (!cfqgd) {
- ret = -EINVAL;
- goto out;
- }
-
- if (!is_leaf_weight)
- cfqgd->weight = val;
- else
- cfqgd->leaf_weight = val;
-
- hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
- struct cfq_group *cfqg = blkg_to_cfqg(blkg);
-
- if (!cfqg)
- continue;
-
- if (!is_leaf_weight) {
- if (reset_dev)
- cfqg->dev_weight = 0;
- if (!cfqg->dev_weight)
- cfqg->new_weight = cfqgd->weight;
- } else {
- if (reset_dev)
- cfqg->dev_leaf_weight = 0;
- if (!cfqg->dev_leaf_weight)
- cfqg->new_leaf_weight = cfqgd->leaf_weight;
- }
- }
-
-out:
- spin_unlock_irq(&blkcg->lock);
- return ret;
-}
-
-static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
- u64 val)
-{
- return __cfq_set_weight(css, val, false, false, false);
-}
-
-static int cfq_set_leaf_weight(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 val)
-{
- return __cfq_set_weight(css, val, false, false, true);
-}
-
-static int cfqg_print_stat(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
- &blkcg_policy_cfq, seq_cft(sf)->private, false);
- return 0;
-}
-
-static int cfqg_print_rwstat(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
- &blkcg_policy_cfq, seq_cft(sf)->private, true);
- return 0;
-}
-
-static u64 cfqg_prfill_stat_recursive(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd),
- &blkcg_policy_cfq, off);
- return __blkg_prfill_u64(sf, pd, sum);
-}
-
-static u64 cfqg_prfill_rwstat_recursive(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- struct blkg_rwstat sum = blkg_rwstat_recursive_sum(pd_to_blkg(pd),
- &blkcg_policy_cfq, off);
- return __blkg_prfill_rwstat(sf, pd, &sum);
-}
-
-static int cfqg_print_stat_recursive(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_stat_recursive, &blkcg_policy_cfq,
- seq_cft(sf)->private, false);
- return 0;
-}
-
-static int cfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_rwstat_recursive, &blkcg_policy_cfq,
- seq_cft(sf)->private, true);
- return 0;
-}
-
-static u64 cfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
- int off)
-{
- u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes);
-
- return __blkg_prfill_u64(sf, pd, sum >> 9);
-}
-
-static int cfqg_print_stat_sectors(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_sectors, &blkcg_policy_cfq, 0, false);
- return 0;
-}
-
-static u64 cfqg_prfill_sectors_recursive(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL,
- offsetof(struct blkcg_gq, stat_bytes));
- u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
- atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
-
- return __blkg_prfill_u64(sf, pd, sum >> 9);
-}
-
-static int cfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_sectors_recursive, &blkcg_policy_cfq, 0,
- false);
- return 0;
-}
-
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,
- struct blkg_policy_data *pd, int off)
-{
- struct cfq_group *cfqg = pd_to_cfqg(pd);
- u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples);
- u64 v = 0;
-
- if (samples) {
- v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum);
- v = div64_u64(v, samples);
- }
- __blkg_prfill_u64(sf, pd, v);
- return 0;
-}
-
-/* print avg_queue_size */
-static int cfqg_print_avg_queue_size(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
- cfqg_prfill_avg_queue_size, &blkcg_policy_cfq,
- 0, false);
- return 0;
-}
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
-
-static struct cftype cfq_blkcg_legacy_files[] = {
- /* on root, weight is mapped to leaf_weight */
- {
- .name = "weight_device",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .seq_show = cfqg_print_leaf_weight_device,
- .write = cfqg_set_leaf_weight_device,
- },
- {
- .name = "weight",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .seq_show = cfq_print_leaf_weight,
- .write_u64 = cfq_set_leaf_weight,
- },
-
- /* no such mapping necessary for !roots */
- {
- .name = "weight_device",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cfqg_print_weight_device,
- .write = cfqg_set_weight_device,
- },
- {
- .name = "weight",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cfq_print_weight,
- .write_u64 = cfq_set_weight,
- },
-
- {
- .name = "leaf_weight_device",
- .seq_show = cfqg_print_leaf_weight_device,
- .write = cfqg_set_leaf_weight_device,
- },
- {
- .name = "leaf_weight",
- .seq_show = cfq_print_leaf_weight,
- .write_u64 = cfq_set_leaf_weight,
- },
-
- /* statistics, covers only the tasks in the cfqg */
- {
- .name = "time",
- .private = offsetof(struct cfq_group, stats.time),
- .seq_show = cfqg_print_stat,
- },
- {
- .name = "sectors",
- .seq_show = cfqg_print_stat_sectors,
- },
- {
- .name = "io_service_bytes",
- .private = (unsigned long)&blkcg_policy_cfq,
- .seq_show = blkg_print_stat_bytes,
- },
- {
- .name = "io_serviced",
- .private = (unsigned long)&blkcg_policy_cfq,
- .seq_show = blkg_print_stat_ios,
- },
- {
- .name = "io_service_time",
- .private = offsetof(struct cfq_group, stats.service_time),
- .seq_show = cfqg_print_rwstat,
- },
- {
- .name = "io_wait_time",
- .private = offsetof(struct cfq_group, stats.wait_time),
- .seq_show = cfqg_print_rwstat,
- },
- {
- .name = "io_merged",
- .private = offsetof(struct cfq_group, stats.merged),
- .seq_show = cfqg_print_rwstat,
- },
- {
- .name = "io_queued",
- .private = offsetof(struct cfq_group, stats.queued),
- .seq_show = cfqg_print_rwstat,
- },
-
- /* the same statictics which cover the cfqg and its descendants */
- {
- .name = "time_recursive",
- .private = offsetof(struct cfq_group, stats.time),
- .seq_show = cfqg_print_stat_recursive,
- },
- {
- .name = "sectors_recursive",
- .seq_show = cfqg_print_stat_sectors_recursive,
- },
- {
- .name = "io_service_bytes_recursive",
- .private = (unsigned long)&blkcg_policy_cfq,
- .seq_show = blkg_print_stat_bytes_recursive,
- },
- {
- .name = "io_serviced_recursive",
- .private = (unsigned long)&blkcg_policy_cfq,
- .seq_show = blkg_print_stat_ios_recursive,
- },
- {
- .name = "io_service_time_recursive",
- .private = offsetof(struct cfq_group, stats.service_time),
- .seq_show = cfqg_print_rwstat_recursive,
- },
- {
- .name = "io_wait_time_recursive",
- .private = offsetof(struct cfq_group, stats.wait_time),
- .seq_show = cfqg_print_rwstat_recursive,
- },
- {
- .name = "io_merged_recursive",
- .private = offsetof(struct cfq_group, stats.merged),
- .seq_show = cfqg_print_rwstat_recursive,
- },
- {
- .name = "io_queued_recursive",
- .private = offsetof(struct cfq_group, stats.queued),
- .seq_show = cfqg_print_rwstat_recursive,
- },
-#ifdef CONFIG_DEBUG_BLK_CGROUP
- {
- .name = "avg_queue_size",
- .seq_show = cfqg_print_avg_queue_size,
- },
- {
- .name = "group_wait_time",
- .private = offsetof(struct cfq_group, stats.group_wait_time),
- .seq_show = cfqg_print_stat,
- },
- {
- .name = "idle_time",
- .private = offsetof(struct cfq_group, stats.idle_time),
- .seq_show = cfqg_print_stat,
- },
- {
- .name = "empty_time",
- .private = offsetof(struct cfq_group, stats.empty_time),
- .seq_show = cfqg_print_stat,
- },
- {
- .name = "dequeue",
- .private = offsetof(struct cfq_group, stats.dequeue),
- .seq_show = cfqg_print_stat,
- },
- {
- .name = "unaccounted_time",
- .private = offsetof(struct cfq_group, stats.unaccounted_time),
- .seq_show = cfqg_print_stat,
- },
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
- { } /* terminate */
-};
-
-static int cfq_print_weight_on_dfl(struct seq_file *sf, void *v)
-{
- struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
- struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
-
- seq_printf(sf, "default %u\n", cgd->weight);
- blkcg_print_blkgs(sf, blkcg, cfqg_prfill_weight_device,
- &blkcg_policy_cfq, 0, false);
- return 0;
-}
-
-static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
-{
- char *endp;
- int ret;
- u64 v;
-
- buf = strim(buf);
-
- /* "WEIGHT" or "default WEIGHT" sets the default weight */
- v = simple_strtoull(buf, &endp, 0);
- if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
- ret = __cfq_set_weight(of_css(of), v, true, false, false);
- return ret ?: nbytes;
- }
-
- /* "MAJ:MIN WEIGHT" */
- return __cfqg_set_weight_device(of, buf, nbytes, off, true, false);
-}
-
-static struct cftype cfq_blkcg_files[] = {
- {
- .name = "weight",
- .flags = CFTYPE_NOT_ON_ROOT,
- .seq_show = cfq_print_weight_on_dfl,
- .write = cfq_set_weight_on_dfl,
- },
- { } /* terminate */
-};
-
-#else /* GROUP_IOSCHED */
-static struct cfq_group *cfq_lookup_cfqg(struct cfq_data *cfqd,
- struct blkcg *blkcg)
-{
- return cfqd->root_group;
-}
-
-static inline void
-cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) {
- cfqq->cfqg = cfqg;
-}
-
-#endif /* GROUP_IOSCHED */
-
-/*
- * The cfqd->service_trees holds all pending cfq_queue's that have
- * requests waiting to be processed. It is sorted in the order that
- * we will service the queues.
- */
-static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- bool add_front)
-{
- struct rb_node **p, *parent;
- struct cfq_queue *__cfqq;
- u64 rb_key;
- struct cfq_rb_root *st;
- bool leftmost = true;
- int new_cfqq = 1;
- u64 now = ktime_get_ns();
-
- st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq));
- if (cfq_class_idle(cfqq)) {
- rb_key = CFQ_IDLE_DELAY;
- parent = st->rb_rightmost;
- if (parent && parent != &cfqq->rb_node) {
- __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
- rb_key += __cfqq->rb_key;
- } else
- rb_key += now;
- } else if (!add_front) {
- /*
- * Get our rb key offset. Subtract any residual slice
- * value carried from last service. A negative resid
- * count indicates slice overrun, and this should position
- * the next service time further away in the tree.
- */
- rb_key = cfq_slice_offset(cfqd, cfqq) + now;
- rb_key -= cfqq->slice_resid;
- cfqq->slice_resid = 0;
- } else {
- rb_key = -NSEC_PER_SEC;
- __cfqq = cfq_rb_first(st);
- rb_key += __cfqq ? __cfqq->rb_key : now;
- }
-
- if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
- new_cfqq = 0;
- /*
- * same position, nothing more to do
- */
- if (rb_key == cfqq->rb_key && cfqq->service_tree == st)
- return;
-
- cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
- cfqq->service_tree = NULL;
- }
-
- parent = NULL;
- cfqq->service_tree = st;
- p = &st->rb.rb_root.rb_node;
- while (*p) {
- parent = *p;
- __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-
- /*
- * sort by key, that represents service time.
- */
- if (rb_key < __cfqq->rb_key)
- p = &parent->rb_left;
- else {
- p = &parent->rb_right;
- leftmost = false;
- }
- }
-
- cfqq->rb_key = rb_key;
- rb_link_node(&cfqq->rb_node, parent, p);
- rb_insert_color_cached(&cfqq->rb_node, &st->rb, leftmost);
- st->count++;
- if (add_front || !new_cfqq)
- return;
- cfq_group_notify_queue_add(cfqd, cfqq->cfqg);
-}
-
-static struct cfq_queue *
-cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
- sector_t sector, struct rb_node **ret_parent,
- struct rb_node ***rb_link)
-{
- struct rb_node **p, *parent;
- struct cfq_queue *cfqq = NULL;
-
- parent = NULL;
- p = &root->rb_node;
- while (*p) {
- struct rb_node **n;
-
- parent = *p;
- cfqq = rb_entry(parent, struct cfq_queue, p_node);
-
- /*
- * Sort strictly based on sector. Smallest to the left,
- * largest to the right.
- */
- if (sector > blk_rq_pos(cfqq->next_rq))
- n = &(*p)->rb_right;
- else if (sector < blk_rq_pos(cfqq->next_rq))
- n = &(*p)->rb_left;
- else
- break;
- p = n;
- cfqq = NULL;
- }
-
- *ret_parent = parent;
- if (rb_link)
- *rb_link = p;
- return cfqq;
-}
-
-static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- struct rb_node **p, *parent;
- struct cfq_queue *__cfqq;
-
- if (cfqq->p_root) {
- rb_erase(&cfqq->p_node, cfqq->p_root);
- cfqq->p_root = NULL;
- }
-
- if (cfq_class_idle(cfqq))
- return;
- if (!cfqq->next_rq)
- return;
-
- cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio];
- __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root,
- blk_rq_pos(cfqq->next_rq), &parent, &p);
- if (!__cfqq) {
- rb_link_node(&cfqq->p_node, parent, p);
- rb_insert_color(&cfqq->p_node, cfqq->p_root);
- } else
- cfqq->p_root = NULL;
-}
-
-/*
- * Update cfqq's position in the service tree.
- */
-static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- /*
- * Resorting requires the cfqq to be on the RR list already.
- */
- if (cfq_cfqq_on_rr(cfqq)) {
- cfq_service_tree_add(cfqd, cfqq, 0);
- cfq_prio_tree_add(cfqd, cfqq);
- }
-}
-
-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
- BUG_ON(cfq_cfqq_on_rr(cfqq));
- cfq_mark_cfqq_on_rr(cfqq);
- cfqd->busy_queues++;
- if (cfq_cfqq_sync(cfqq))
- cfqd->busy_sync_queues++;
-
- cfq_resort_rr_list(cfqd, cfqq);
-}
-
-/*
- * Called when the cfqq no longer has requests pending, remove it from
- * the service tree.
- */
-static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
- cfq_clear_cfqq_on_rr(cfqq);
-
- if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
- cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
- cfqq->service_tree = NULL;
- }
- if (cfqq->p_root) {
- rb_erase(&cfqq->p_node, cfqq->p_root);
- cfqq->p_root = NULL;
- }
-
- cfq_group_notify_queue_del(cfqd, cfqq->cfqg);
- BUG_ON(!cfqd->busy_queues);
- cfqd->busy_queues--;
- if (cfq_cfqq_sync(cfqq))
- cfqd->busy_sync_queues--;
-}
-
-/*
- * rb tree support functions
- */
-static void cfq_del_rq_rb(struct request *rq)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- const int sync = rq_is_sync(rq);
-
- BUG_ON(!cfqq->queued[sync]);
- cfqq->queued[sync]--;
-
- elv_rb_del(&cfqq->sort_list, rq);
-
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) {
- /*
- * Queue will be deleted from service tree when we actually
- * expire it later. Right now just remove it from prio tree
- * as it is empty.
- */
- if (cfqq->p_root) {
- rb_erase(&cfqq->p_node, cfqq->p_root);
- cfqq->p_root = NULL;
- }
- }
-}
-
-static void cfq_add_rq_rb(struct request *rq)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
- struct request *prev;
-
- cfqq->queued[rq_is_sync(rq)]++;
-
- elv_rb_add(&cfqq->sort_list, rq);
-
- if (!cfq_cfqq_on_rr(cfqq))
- cfq_add_cfqq_rr(cfqd, cfqq);
-
- /*
- * check if this request is a better next-serve candidate
- */
- prev = cfqq->next_rq;
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position);
-
- /*
- * adjust priority tree position, if ->next_rq changes
- */
- if (prev != cfqq->next_rq)
- cfq_prio_tree_add(cfqd, cfqq);
-
- BUG_ON(!cfqq->next_rq);
-}
-
-static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
-{
- elv_rb_del(&cfqq->sort_list, rq);
- cfqq->queued[rq_is_sync(rq)]--;
- cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
- cfq_add_rq_rb(rq);
- cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group,
- rq->cmd_flags);
-}
-
-static struct request *
-cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
-{
- struct task_struct *tsk = current;
- struct cfq_io_cq *cic;
- struct cfq_queue *cfqq;
-
- cic = cfq_cic_lookup(cfqd, tsk->io_context);
- if (!cic)
- return NULL;
-
- cfqq = cic_to_cfqq(cic, op_is_sync(bio->bi_opf));
- if (cfqq)
- return elv_rb_find(&cfqq->sort_list, bio_end_sector(bio));
-
- return NULL;
-}
-
-static void cfq_activate_request(struct request_queue *q, struct request *rq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- cfqd->rq_in_driver++;
- cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
- cfqd->rq_in_driver);
-
- cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
-}
-
-static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
- cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
- cfqd->rq_in_driver);
-}
-
-static void cfq_remove_request(struct request *rq)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
- if (cfqq->next_rq == rq)
- cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
-
- list_del_init(&rq->queuelist);
- cfq_del_rq_rb(rq);
-
- cfqq->cfqd->rq_queued--;
- cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
- if (rq->cmd_flags & REQ_PRIO) {
- WARN_ON(!cfqq->prio_pending);
- cfqq->prio_pending--;
- }
-}
-
-static enum elv_merge cfq_merge(struct request_queue *q, struct request **req,
- struct bio *bio)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct request *__rq;
-
- __rq = cfq_find_rq_fmerge(cfqd, bio);
- if (__rq && elv_bio_merge_ok(__rq, bio)) {
- *req = __rq;
- return ELEVATOR_FRONT_MERGE;
- }
-
- return ELEVATOR_NO_MERGE;
-}
-
-static void cfq_merged_request(struct request_queue *q, struct request *req,
- enum elv_merge type)
-{
- if (type == ELEVATOR_FRONT_MERGE) {
- struct cfq_queue *cfqq = RQ_CFQQ(req);
-
- cfq_reposition_rq_rb(cfqq, req);
- }
-}
-
-static void cfq_bio_merged(struct request_queue *q, struct request *req,
- struct bio *bio)
-{
- cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_opf);
-}
-
-static void
-cfq_merged_requests(struct request_queue *q, struct request *rq,
- struct request *next)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- /*
- * reposition in fifo if next is older than rq
- */
- if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
- next->fifo_time < rq->fifo_time &&
- cfqq == RQ_CFQQ(next)) {
- list_move(&rq->queuelist, &next->queuelist);
- rq->fifo_time = next->fifo_time;
- }
-
- if (cfqq->next_rq == next)
- cfqq->next_rq = rq;
- cfq_remove_request(next);
- cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags);
-
- cfqq = RQ_CFQQ(next);
- /*
- * all requests of this queue are merged to other queues, delete it
- * from the service tree. If it's the active_queue,
- * cfq_dispatch_requests() will choose to expire it or do idle
- */
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) &&
- cfqq != cfqd->active_queue)
- cfq_del_cfqq_rr(cfqd, cfqq);
-}
-
-static int cfq_allow_bio_merge(struct request_queue *q, struct request *rq,
- struct bio *bio)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- bool is_sync = op_is_sync(bio->bi_opf);
- struct cfq_io_cq *cic;
- struct cfq_queue *cfqq;
-
- /*
- * Disallow merge of a sync bio into an async request.
- */
- if (is_sync && !rq_is_sync(rq))
- return false;
-
- /*
- * Lookup the cfqq that this bio will be queued with and allow
- * merge only if rq is queued there.
- */
- cic = cfq_cic_lookup(cfqd, current->io_context);
- if (!cic)
- return false;
-
- cfqq = cic_to_cfqq(cic, is_sync);
- return cfqq == RQ_CFQQ(rq);
-}
-
-static int cfq_allow_rq_merge(struct request_queue *q, struct request *rq,
- struct request *next)
-{
- return RQ_CFQQ(rq) == RQ_CFQQ(next);
-}
-
-static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- hrtimer_try_to_cancel(&cfqd->idle_slice_timer);
- cfqg_stats_update_idle_time(cfqq->cfqg);
-}
-
-static void __cfq_set_active_queue(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- if (cfqq) {
- cfq_log_cfqq(cfqd, cfqq, "set_active wl_class:%d wl_type:%d",
- cfqd->serving_wl_class, cfqd->serving_wl_type);
- cfqg_stats_update_avg_queue_size(cfqq->cfqg);
- cfqq->slice_start = 0;
- cfqq->dispatch_start = ktime_get_ns();
- cfqq->allocated_slice = 0;
- cfqq->slice_end = 0;
- cfqq->slice_dispatch = 0;
- cfqq->nr_sectors = 0;
-
- cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_must_alloc_slice(cfqq);
- cfq_clear_cfqq_fifo_expire(cfqq);
- cfq_mark_cfqq_slice_new(cfqq);
-
- cfq_del_timer(cfqd, cfqq);
- }
-
- cfqd->active_queue = cfqq;
-}
-
-/*
- * current cfqq expired its slice (or was too idle), select new one
- */
-static void
-__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- bool timed_out)
-{
- cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
-
- if (cfq_cfqq_wait_request(cfqq))
- cfq_del_timer(cfqd, cfqq);
-
- cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_wait_busy(cfqq);
-
- /*
- * If this cfqq is shared between multiple processes, check to
- * make sure that those processes are still issuing I/Os within
- * the mean seek distance. If not, it may be time to break the
- * queues apart again.
- */
- if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq))
- cfq_mark_cfqq_split_coop(cfqq);
-
- /*
- * store what was left of this slice, if the queue idled/timed out
- */
- if (timed_out) {
- if (cfq_cfqq_slice_new(cfqq))
- cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
- else
- cfqq->slice_resid = cfqq->slice_end - ktime_get_ns();
- cfq_log_cfqq(cfqd, cfqq, "resid=%lld", cfqq->slice_resid);
- }
-
- cfq_group_served(cfqd, cfqq->cfqg, cfqq);
-
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
- cfq_del_cfqq_rr(cfqd, cfqq);
-
- cfq_resort_rr_list(cfqd, cfqq);
-
- if (cfqq == cfqd->active_queue)
- cfqd->active_queue = NULL;
-
- if (cfqd->active_cic) {
- put_io_context(cfqd->active_cic->icq.ioc);
- cfqd->active_cic = NULL;
- }
-}
-
-static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
-{
- struct cfq_queue *cfqq = cfqd->active_queue;
-
- if (cfqq)
- __cfq_slice_expired(cfqd, cfqq, timed_out);
-}
-
-/*
- * Get next queue for service. Unless we have a queue preemption,
- * we'll simply select the first cfqq in the service tree.
- */
-static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
-{
- struct cfq_rb_root *st = st_for(cfqd->serving_group,
- cfqd->serving_wl_class, cfqd->serving_wl_type);
-
- if (!cfqd->rq_queued)
- return NULL;
-
- /* There is nothing to dispatch */
- if (!st)
- return NULL;
- if (RB_EMPTY_ROOT(&st->rb.rb_root))
- return NULL;
- return cfq_rb_first(st);
-}
-
-static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd)
-{
- struct cfq_group *cfqg;
- struct cfq_queue *cfqq;
- int i, j;
- struct cfq_rb_root *st;
-
- if (!cfqd->rq_queued)
- return NULL;
-
- cfqg = cfq_get_next_cfqg(cfqd);
- if (!cfqg)
- return NULL;
-
- for_each_cfqg_st(cfqg, i, j, st) {
- cfqq = cfq_rb_first(st);
- if (cfqq)
- return cfqq;
- }
- return NULL;
-}
-
-/*
- * Get and set a new active queue for service.
- */
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- if (!cfqq)
- cfqq = cfq_get_next_queue(cfqd);
-
- __cfq_set_active_queue(cfqd, cfqq);
- return cfqq;
-}
-
-static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
- struct request *rq)
-{
- if (blk_rq_pos(rq) >= cfqd->last_position)
- return blk_rq_pos(rq) - cfqd->last_position;
- else
- return cfqd->last_position - blk_rq_pos(rq);
-}
-
-static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *rq)
-{
- return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR;
-}
-
-static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
- struct cfq_queue *cur_cfqq)
-{
- struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio];
- struct rb_node *parent, *node;
- struct cfq_queue *__cfqq;
- sector_t sector = cfqd->last_position;
-
- if (RB_EMPTY_ROOT(root))
- return NULL;
-
- /*
- * First, if we find a request starting at the end of the last
- * request, choose it.
- */
- __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL);
- if (__cfqq)
- return __cfqq;
-
- /*
- * If the exact sector wasn't found, the parent of the NULL leaf
- * will contain the closest sector.
- */
- __cfqq = rb_entry(parent, struct cfq_queue, p_node);
- if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
- return __cfqq;
-
- if (blk_rq_pos(__cfqq->next_rq) < sector)
- node = rb_next(&__cfqq->p_node);
- else
- node = rb_prev(&__cfqq->p_node);
- if (!node)
- return NULL;
-
- __cfqq = rb_entry(node, struct cfq_queue, p_node);
- if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
- return __cfqq;
-
- return NULL;
-}
-
-/*
- * cfqd - obvious
- * cur_cfqq - passed in so that we don't decide that the current queue is
- * closely cooperating with itself.
- *
- * So, basically we're assuming that that cur_cfqq has dispatched at least
- * one request, and that cfqd->last_position reflects a position on the disk
- * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
- * assumption.
- */
-static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
- struct cfq_queue *cur_cfqq)
-{
- struct cfq_queue *cfqq;
-
- if (cfq_class_idle(cur_cfqq))
- return NULL;
- if (!cfq_cfqq_sync(cur_cfqq))
- return NULL;
- if (CFQQ_SEEKY(cur_cfqq))
- return NULL;
-
- /*
- * Don't search priority tree if it's the only queue in the group.
- */
- if (cur_cfqq->cfqg->nr_cfqq == 1)
- return NULL;
-
- /*
- * We should notice if some of the queues are cooperating, eg
- * working closely on the same area of the disk. In that case,
- * we can group them together and don't waste time idling.
- */
- cfqq = cfqq_close(cfqd, cur_cfqq);
- if (!cfqq)
- return NULL;
-
- /* If new queue belongs to different cfq_group, don't choose it */
- if (cur_cfqq->cfqg != cfqq->cfqg)
- return NULL;
-
- /*
- * It only makes sense to merge sync queues.
- */
- if (!cfq_cfqq_sync(cfqq))
- return NULL;
- if (CFQQ_SEEKY(cfqq))
- return NULL;
-
- /*
- * Do not merge queues of different priority classes
- */
- if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq))
- return NULL;
-
- return cfqq;
-}
-
-/*
- * Determine whether we should enforce idle window for this queue.
- */
-
-static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- enum wl_class_t wl_class = cfqq_class(cfqq);
- struct cfq_rb_root *st = cfqq->service_tree;
-
- BUG_ON(!st);
- BUG_ON(!st->count);
-
- if (!cfqd->cfq_slice_idle)
- return false;
-
- /* We never do for idle class queues. */
- if (wl_class == IDLE_WORKLOAD)
- return false;
-
- /* We do for queues that were marked with idle window flag. */
- if (cfq_cfqq_idle_window(cfqq) &&
- !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
- return true;
-
- /*
- * Otherwise, we do only if they are the last ones
- * in their service tree.
- */
- if (st->count == 1 && cfq_cfqq_sync(cfqq) &&
- !cfq_io_thinktime_big(cfqd, &st->ttime, false))
- return true;
- cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", st->count);
- return false;
-}
-
-static void cfq_arm_slice_timer(struct cfq_data *cfqd)
-{
- struct cfq_queue *cfqq = cfqd->active_queue;
- struct cfq_rb_root *st = cfqq->service_tree;
- struct cfq_io_cq *cic;
- u64 sl, group_idle = 0;
- u64 now = ktime_get_ns();
-
- /*
- * SSD device without seek penalty, disable idling. But only do so
- * for devices that support queuing, otherwise we still have a problem
- * with sync vs async workloads.
- */
- if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag &&
- !cfqd->cfq_group_idle)
- return;
-
- WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
- WARN_ON(cfq_cfqq_slice_new(cfqq));
-
- /*
- * idle is disabled, either manually or by past process history
- */
- if (!cfq_should_idle(cfqd, cfqq)) {
- /* no queue idling. Check for group idling */
- if (cfqd->cfq_group_idle)
- group_idle = cfqd->cfq_group_idle;
- else
- return;
- }
-
- /*
- * still active requests from this queue, don't idle
- */
- if (cfqq->dispatched)
- return;
-
- /*
- * task has exited, don't wait
- */
- cic = cfqd->active_cic;
- if (!cic || !atomic_read(&cic->icq.ioc->active_ref))
- return;
-
- /*
- * If our average think time is larger than the remaining time
- * slice, then don't idle. This avoids overrunning the allotted
- * time slice.
- */
- if (sample_valid(cic->ttime.ttime_samples) &&
- (cfqq->slice_end - now < cic->ttime.ttime_mean)) {
- cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%llu",
- cic->ttime.ttime_mean);
- return;
- }
-
- /*
- * There are other queues in the group or this is the only group and
- * it has too big thinktime, don't do group idle.
- */
- if (group_idle &&
- (cfqq->cfqg->nr_cfqq > 1 ||
- cfq_io_thinktime_big(cfqd, &st->ttime, true)))
- return;
-
- cfq_mark_cfqq_wait_request(cfqq);
-
- if (group_idle)
- sl = cfqd->cfq_group_idle;
- else
- sl = cfqd->cfq_slice_idle;
-
- hrtimer_start(&cfqd->idle_slice_timer, ns_to_ktime(sl),
- HRTIMER_MODE_REL);
- cfqg_stats_set_start_idle_time(cfqq->cfqg);
- cfq_log_cfqq(cfqd, cfqq, "arm_idle: %llu group_idle: %d", sl,
- group_idle ? 1 : 0);
-}
-
-/*
- * Move request from internal lists to the request queue dispatch list.
- */
-static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
- cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
-
- cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
- cfq_remove_request(rq);
- cfqq->dispatched++;
- (RQ_CFQG(rq))->dispatched++;
- elv_dispatch_sort(q, rq);
-
- cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;
- cfqq->nr_sectors += blk_rq_sectors(rq);
-}
-
-/*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
-static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
-{
- struct request *rq = NULL;
-
- if (cfq_cfqq_fifo_expire(cfqq))
- return NULL;
-
- cfq_mark_cfqq_fifo_expire(cfqq);
-
- if (list_empty(&cfqq->fifo))
- return NULL;
-
- rq = rq_entry_fifo(cfqq->fifo.next);
- if (ktime_get_ns() < rq->fifo_time)
- rq = NULL;
-
- return rq;
-}
-
-static inline int
-cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- const int base_rq = cfqd->cfq_slice_async_rq;
-
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
-
- return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio);
-}
-
-/*
- * Must be called with the queue_lock held.
- */
-static int cfqq_process_refs(struct cfq_queue *cfqq)
-{
- int process_refs, io_refs;
-
- io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
- process_refs = cfqq->ref - io_refs;
- BUG_ON(process_refs < 0);
- return process_refs;
-}
-
-static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
-{
- int process_refs, new_process_refs;
- struct cfq_queue *__cfqq;
-
- /*
- * If there are no process references on the new_cfqq, then it is
- * unsafe to follow the ->new_cfqq chain as other cfqq's in the
- * chain may have dropped their last reference (not just their
- * last process reference).
- */
- if (!cfqq_process_refs(new_cfqq))
- return;
-
- /* Avoid a circular list and skip interim queue merges */
- while ((__cfqq = new_cfqq->new_cfqq)) {
- if (__cfqq == cfqq)
- return;
- new_cfqq = __cfqq;
- }
-
- process_refs = cfqq_process_refs(cfqq);
- new_process_refs = cfqq_process_refs(new_cfqq);
- /*
- * If the process for the cfqq has gone away, there is no
- * sense in merging the queues.
- */
- if (process_refs == 0 || new_process_refs == 0)
- return;
-
- /*
- * Merge in the direction of the lesser amount of work.
- */
- if (new_process_refs >= process_refs) {
- cfqq->new_cfqq = new_cfqq;
- new_cfqq->ref += process_refs;
- } else {
- new_cfqq->new_cfqq = cfqq;
- cfqq->ref += new_process_refs;
- }
-}
-
-static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd,
- struct cfq_group *cfqg, enum wl_class_t wl_class)
-{
- struct cfq_queue *queue;
- int i;
- bool key_valid = false;
- u64 lowest_key = 0;
- enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
-
- for (i = 0; i <= SYNC_WORKLOAD; ++i) {
- /* select the one with lowest rb_key */
- queue = cfq_rb_first(st_for(cfqg, wl_class, i));
- if (queue &&
- (!key_valid || queue->rb_key < lowest_key)) {
- lowest_key = queue->rb_key;
- cur_best = i;
- key_valid = true;
- }
- }
-
- return cur_best;
-}
-
-static void
-choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg)
-{
- u64 slice;
- unsigned count;
- struct cfq_rb_root *st;
- u64 group_slice;
- enum wl_class_t original_class = cfqd->serving_wl_class;
- u64 now = ktime_get_ns();
-
- /* Choose next priority. RT > BE > IDLE */
- if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
- cfqd->serving_wl_class = RT_WORKLOAD;
- else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg))
- cfqd->serving_wl_class = BE_WORKLOAD;
- else {
- cfqd->serving_wl_class = IDLE_WORKLOAD;
- cfqd->workload_expires = now + jiffies_to_nsecs(1);
- return;
- }
-
- if (original_class != cfqd->serving_wl_class)
- goto new_workload;
-
- /*
- * For RT and BE, we have to choose also the type
- * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
- * expiration time
- */
- st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type);
- count = st->count;
-
- /*
- * check workload expiration, and that we still have other queues ready
- */
- if (count && !(now > cfqd->workload_expires))
- return;
-
-new_workload:
- /* otherwise select new workload type */
- cfqd->serving_wl_type = cfq_choose_wl_type(cfqd, cfqg,
- cfqd->serving_wl_class);
- st = st_for(cfqg, cfqd->serving_wl_class, cfqd->serving_wl_type);
- count = st->count;
-
- /*
- * the workload slice is computed as a fraction of target latency
- * proportional to the number of queues in that workload, over
- * all the queues in the same priority class
- */
- group_slice = cfq_group_slice(cfqd, cfqg);
-
- slice = div_u64(group_slice * count,
- max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_wl_class],
- cfq_group_busy_queues_wl(cfqd->serving_wl_class, cfqd,
- cfqg)));
-
- if (cfqd->serving_wl_type == ASYNC_WORKLOAD) {
- u64 tmp;
-
- /*
- * Async queues are currently system wide. Just taking
- * proportion of queues with-in same group will lead to higher
- * async ratio system wide as generally root group is going
- * to have higher weight. A more accurate thing would be to
- * calculate system wide asnc/sync ratio.
- */
- tmp = cfqd->cfq_target_latency *
- cfqg_busy_async_queues(cfqd, cfqg);
- tmp = div_u64(tmp, cfqd->busy_queues);
- slice = min_t(u64, slice, tmp);
-
- /* async workload slice is scaled down according to
- * the sync/async slice ratio. */
- slice = div64_u64(slice*cfqd->cfq_slice[0], cfqd->cfq_slice[1]);
- } else
- /* sync workload slice is at least 2 * cfq_slice_idle */
- slice = max(slice, 2 * cfqd->cfq_slice_idle);
-
- slice = max_t(u64, slice, CFQ_MIN_TT);
- cfq_log(cfqd, "workload slice:%llu", slice);
- cfqd->workload_expires = now + slice;
-}
-
-static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
-{
- struct cfq_rb_root *st = &cfqd->grp_service_tree;
- struct cfq_group *cfqg;
-
- if (RB_EMPTY_ROOT(&st->rb.rb_root))
- return NULL;
- cfqg = cfq_rb_first_group(st);
- update_min_vdisktime(st);
- return cfqg;
-}
-
-static void cfq_choose_cfqg(struct cfq_data *cfqd)
-{
- struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd);
- u64 now = ktime_get_ns();
-
- cfqd->serving_group = cfqg;
-
- /* Restore the workload type data */
- if (cfqg->saved_wl_slice) {
- cfqd->workload_expires = now + cfqg->saved_wl_slice;
- cfqd->serving_wl_type = cfqg->saved_wl_type;
- cfqd->serving_wl_class = cfqg->saved_wl_class;
- } else
- cfqd->workload_expires = now - 1;
-
- choose_wl_class_and_type(cfqd, cfqg);
-}
-
-/*
- * Select a queue for service. If we have a current active queue,
- * check whether to continue servicing it, or retrieve and set a new one.
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
-{
- struct cfq_queue *cfqq, *new_cfqq = NULL;
- u64 now = ktime_get_ns();
-
- cfqq = cfqd->active_queue;
- if (!cfqq)
- goto new_queue;
-
- if (!cfqd->rq_queued)
- return NULL;
-
- /*
- * We were waiting for group to get backlogged. Expire the queue
- */
- if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
- goto expire;
-
- /*
- * The active queue has run out of time, expire it and select new.
- */
- if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) {
- /*
- * If slice had not expired at the completion of last request
- * we might not have turned on wait_busy flag. Don't expire
- * the queue yet. Allow the group to get backlogged.
- *
- * The very fact that we have used the slice, that means we
- * have been idling all along on this queue and it should be
- * ok to wait for this request to complete.
- */
- if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list)
- && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
- cfqq = NULL;
- goto keep_queue;
- } else
- goto check_group_idle;
- }
-
- /*
- * The active queue has requests and isn't expired, allow it to
- * dispatch.
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- goto keep_queue;
-
- /*
- * If another queue has a request waiting within our mean seek
- * distance, let it run. The expire code will check for close
- * cooperators and put the close queue at the front of the service
- * tree. If possible, merge the expiring queue with the new cfqq.
- */
- new_cfqq = cfq_close_cooperator(cfqd, cfqq);
- if (new_cfqq) {
- if (!cfqq->new_cfqq)
- cfq_setup_merge(cfqq, new_cfqq);
- goto expire;
- }
-
- /*
- * No requests pending. If the active queue still has requests in
- * flight or is idling for a new request, allow either of these
- * conditions to happen (or time out) before selecting a new queue.
- */
- if (hrtimer_active(&cfqd->idle_slice_timer)) {
- cfqq = NULL;
- goto keep_queue;
- }
-
- /*
- * This is a deep seek queue, but the device is much faster than
- * the queue can deliver, don't idle
- **/
- if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
- (cfq_cfqq_slice_new(cfqq) ||
- (cfqq->slice_end - now > now - cfqq->slice_start))) {
- cfq_clear_cfqq_deep(cfqq);
- cfq_clear_cfqq_idle_window(cfqq);
- }
-
- if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
- cfqq = NULL;
- goto keep_queue;
- }
-
- /*
- * If group idle is enabled and there are requests dispatched from
- * this group, wait for requests to complete.
- */
-check_group_idle:
- if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 &&
- cfqq->cfqg->dispatched &&
- !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) {
- cfqq = NULL;
- goto keep_queue;
- }
-
-expire:
- cfq_slice_expired(cfqd, 0);
-new_queue:
- /*
- * Current queue expired. Check if we have to switch to a new
- * service tree
- */
- if (!new_cfqq)
- cfq_choose_cfqg(cfqd);
-
- cfqq = cfq_set_active_queue(cfqd, new_cfqq);
-keep_queue:
- return cfqq;
-}
-
-static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
-{
- int dispatched = 0;
-
- while (cfqq->next_rq) {
- cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
- dispatched++;
- }
-
- BUG_ON(!list_empty(&cfqq->fifo));
-
- /* By default cfqq is not expired if it is empty. Do it explicitly */
- __cfq_slice_expired(cfqq->cfqd, cfqq, 0);
- return dispatched;
-}
-
-/*
- * Drain our current requests. Used for barriers and when switching
- * io schedulers on-the-fly.
- */
-static int cfq_forced_dispatch(struct cfq_data *cfqd)
-{
- struct cfq_queue *cfqq;
- int dispatched = 0;
-
- /* Expire the timeslice of the current active queue first */
- cfq_slice_expired(cfqd, 0);
- while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) {
- __cfq_set_active_queue(cfqd, cfqq);
- dispatched += __cfq_forced_dispatch_cfqq(cfqq);
- }
-
- BUG_ON(cfqd->busy_queues);
-
- cfq_log(cfqd, "forced_dispatch=%d", dispatched);
- return dispatched;
-}
-
-static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- u64 now = ktime_get_ns();
-
- /* the queue hasn't finished any request, can't estimate */
- if (cfq_cfqq_slice_new(cfqq))
- return true;
- if (now + cfqd->cfq_slice_idle * cfqq->dispatched > cfqq->slice_end)
- return true;
-
- return false;
-}
-
-static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- unsigned int max_dispatch;
-
- if (cfq_cfqq_must_dispatch(cfqq))
- return true;
-
- /*
- * Drain async requests before we start sync IO
- */
- if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_flight[BLK_RW_ASYNC])
- return false;
-
- /*
- * If this is an async queue and we have sync IO in flight, let it wait
- */
- if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq))
- return false;
-
- max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1);
- if (cfq_class_idle(cfqq))
- max_dispatch = 1;
-
- /*
- * Does this cfqq already have too much IO in flight?
- */
- if (cfqq->dispatched >= max_dispatch) {
- bool promote_sync = false;
- /*
- * idle queue must always only have a single IO in flight
- */
- if (cfq_class_idle(cfqq))
- return false;
-
- /*
- * If there is only one sync queue
- * we can ignore async queue here and give the sync
- * queue no dispatch limit. The reason is a sync queue can
- * preempt async queue, limiting the sync queue doesn't make
- * sense. This is useful for aiostress test.
- */
- if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1)
- promote_sync = true;
-
- /*
- * We have other queues, don't allow more IO from this one
- */
- if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) &&
- !promote_sync)
- return false;
-
- /*
- * Sole queue user, no limit
- */
- if (cfqd->busy_queues == 1 || promote_sync)
- max_dispatch = -1;
- else
- /*
- * Normally we start throttling cfqq when cfq_quantum/2
- * requests have been dispatched. But we can drive
- * deeper queue depths at the beginning of slice
- * subjected to upper limit of cfq_quantum.
- * */
- max_dispatch = cfqd->cfq_quantum;
- }
-
- /*
- * Async queues must wait a bit before being allowed dispatch.
- * We also ramp up the dispatch depth gradually for async IO,
- * based on the last sync IO we serviced
- */
- if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
- u64 last_sync = ktime_get_ns() - cfqd->last_delayed_sync;
- unsigned int depth;
-
- depth = div64_u64(last_sync, cfqd->cfq_slice[1]);
- if (!depth && !cfqq->dispatched)
- depth = 1;
- if (depth < max_dispatch)
- max_dispatch = depth;
- }
-
- /*
- * If we're below the current max, allow a dispatch
- */
- return cfqq->dispatched < max_dispatch;
-}
-
-/*
- * Dispatch a request from cfqq, moving them to the request queue
- * dispatch list.
- */
-static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- struct request *rq;
-
- BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
-
- rq = cfq_check_fifo(cfqq);
- if (rq)
- cfq_mark_cfqq_must_dispatch(cfqq);
-
- if (!cfq_may_dispatch(cfqd, cfqq))
- return false;
-
- /*
- * follow expired path, else get first next available
- */
- if (!rq)
- rq = cfqq->next_rq;
- else
- cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
-
- /*
- * insert request into driver dispatch list
- */
- cfq_dispatch_insert(cfqd->queue, rq);
-
- if (!cfqd->active_cic) {
- struct cfq_io_cq *cic = RQ_CIC(rq);
-
- atomic_long_inc(&cic->icq.ioc->refcount);
- cfqd->active_cic = cic;
- }
-
- return true;
-}
-
-/*
- * Find the cfqq that we need to service and move a request from that to the
- * dispatch list
- */
-static int cfq_dispatch_requests(struct request_queue *q, int force)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq;
-
- if (!cfqd->busy_queues)
- return 0;
-
- if (unlikely(force))
- return cfq_forced_dispatch(cfqd);
-
- cfqq = cfq_select_queue(cfqd);
- if (!cfqq)
- return 0;
-
- /*
- * Dispatch a request from this cfqq, if it is allowed
- */
- if (!cfq_dispatch_request(cfqd, cfqq))
- return 0;
-
- cfqq->slice_dispatch++;
- cfq_clear_cfqq_must_dispatch(cfqq);
-
- /*
- * expire an async queue immediately if it has used up its slice. idle
- * queue always expire after 1 dispatch round.
- */
- if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
- cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq))) {
- cfqq->slice_end = ktime_get_ns() + 1;
- cfq_slice_expired(cfqd, 0);
- }
-
- cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
- return 1;
-}
-
-/*
- * task holds one reference to the queue, dropped when task exits. each rq
- * in-flight on this queue also holds a reference, dropped when rq is freed.
- *
- * Each cfq queue took a reference on the parent group. Drop it now.
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
-{
- struct cfq_data *cfqd = cfqq->cfqd;
- struct cfq_group *cfqg;
-
- BUG_ON(cfqq->ref <= 0);
-
- cfqq->ref--;
- if (cfqq->ref)
- return;
-
- cfq_log_cfqq(cfqd, cfqq, "put_queue");
- BUG_ON(rb_first(&cfqq->sort_list));
- BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
- cfqg = cfqq->cfqg;
-
- if (unlikely(cfqd->active_queue == cfqq)) {
- __cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
- }
-
- BUG_ON(cfq_cfqq_on_rr(cfqq));
- kmem_cache_free(cfq_pool, cfqq);
- cfqg_put(cfqg);
-}
-
-static void cfq_put_cooperator(struct cfq_queue *cfqq)
-{
- struct cfq_queue *__cfqq, *next;
-
- /*
- * If this queue was scheduled to merge with another queue, be
- * sure to drop the reference taken on that queue (and others in
- * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
- */
- __cfqq = cfqq->new_cfqq;
- while (__cfqq) {
- if (__cfqq == cfqq) {
- WARN(1, "cfqq->new_cfqq loop detected\n");
- break;
- }
- next = __cfqq->new_cfqq;
- cfq_put_queue(__cfqq);
- __cfqq = next;
- }
-}
-
-static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- if (unlikely(cfqq == cfqd->active_queue)) {
- __cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
- }
-
- cfq_put_cooperator(cfqq);
-
- cfq_put_queue(cfqq);
-}
-
-static void cfq_init_icq(struct io_cq *icq)
-{
- struct cfq_io_cq *cic = icq_to_cic(icq);
-
- cic->ttime.last_end_request = ktime_get_ns();
-}
-
-static void cfq_exit_icq(struct io_cq *icq)
-{
- struct cfq_io_cq *cic = icq_to_cic(icq);
- struct cfq_data *cfqd = cic_to_cfqd(cic);
-
- if (cic_to_cfqq(cic, false)) {
- cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, false));
- cic_set_cfqq(cic, NULL, false);
- }
-
- if (cic_to_cfqq(cic, true)) {
- cfq_exit_cfqq(cfqd, cic_to_cfqq(cic, true));
- cic_set_cfqq(cic, NULL, true);
- }
-}
-
-static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic)
-{
- struct task_struct *tsk = current;
- int ioprio_class;
-
- if (!cfq_cfqq_prio_changed(cfqq))
- return;
-
- ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
- switch (ioprio_class) {
- default:
- printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
- /* fall through */
- case IOPRIO_CLASS_NONE:
- /*
- * no prio set, inherit CPU scheduling settings
- */
- cfqq->ioprio = task_nice_ioprio(tsk);
- cfqq->ioprio_class = task_nice_ioclass(tsk);
- break;
- case IOPRIO_CLASS_RT:
- cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
- cfqq->ioprio_class = IOPRIO_CLASS_RT;
- break;
- case IOPRIO_CLASS_BE:
- cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- break;
- case IOPRIO_CLASS_IDLE:
- cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
- cfqq->ioprio = 7;
- cfq_clear_cfqq_idle_window(cfqq);
- break;
- }
-
- /*
- * keep track of original prio settings in case we have to temporarily
- * elevate the priority of this queue
- */
- cfqq->org_ioprio = cfqq->ioprio;
- cfqq->org_ioprio_class = cfqq->ioprio_class;
- cfq_clear_cfqq_prio_changed(cfqq);
-}
-
-static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
- int ioprio = cic->icq.ioc->ioprio;
- struct cfq_data *cfqd = cic_to_cfqd(cic);
- struct cfq_queue *cfqq;
-
- /*
- * Check whether ioprio has changed. The condition may trigger
- * spuriously on a newly created cic but there's no harm.
- */
- if (unlikely(!cfqd) || likely(cic->ioprio == ioprio))
- return;
-
- cfqq = cic_to_cfqq(cic, false);
- if (cfqq) {
- cfq_put_queue(cfqq);
- cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio);
- cic_set_cfqq(cic, cfqq, false);
- }
-
- cfqq = cic_to_cfqq(cic, true);
- if (cfqq)
- cfq_mark_cfqq_prio_changed(cfqq);
-
- cic->ioprio = ioprio;
-}
-
-static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- pid_t pid, bool is_sync)
-{
- RB_CLEAR_NODE(&cfqq->rb_node);
- RB_CLEAR_NODE(&cfqq->p_node);
- INIT_LIST_HEAD(&cfqq->fifo);
-
- cfqq->ref = 0;
- cfqq->cfqd = cfqd;
-
- cfq_mark_cfqq_prio_changed(cfqq);
-
- if (is_sync) {
- if (!cfq_class_idle(cfqq))
- cfq_mark_cfqq_idle_window(cfqq);
- cfq_mark_cfqq_sync(cfqq);
- }
- cfqq->pid = pid;
-}
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
- struct cfq_data *cfqd = cic_to_cfqd(cic);
- struct cfq_queue *cfqq;
- uint64_t serial_nr;
-
- rcu_read_lock();
- serial_nr = __bio_blkcg(bio)->css.serial_nr;
- rcu_read_unlock();
-
- /*
- * Check whether blkcg has changed. The condition may trigger
- * spuriously on a newly created cic but there's no harm.
- */
- if (unlikely(!cfqd) || likely(cic->blkcg_serial_nr == serial_nr))
- return;
-
- /*
- * Drop reference to queues. New queues will be assigned in new
- * group upon arrival of fresh requests.
- */
- cfqq = cic_to_cfqq(cic, false);
- if (cfqq) {
- cfq_log_cfqq(cfqd, cfqq, "changed cgroup");
- cic_set_cfqq(cic, NULL, false);
- cfq_put_queue(cfqq);
- }
-
- cfqq = cic_to_cfqq(cic, true);
- if (cfqq) {
- cfq_log_cfqq(cfqd, cfqq, "changed cgroup");
- cic_set_cfqq(cic, NULL, true);
- cfq_put_queue(cfqq);
- }
-
- cic->blkcg_serial_nr = serial_nr;
-}
-#else
-static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
-{
-}
-#endif /* CONFIG_CFQ_GROUP_IOSCHED */
-
-static struct cfq_queue **
-cfq_async_queue_prio(struct cfq_group *cfqg, int ioprio_class, int ioprio)
-{
- switch (ioprio_class) {
- case IOPRIO_CLASS_RT:
- return &cfqg->async_cfqq[0][ioprio];
- case IOPRIO_CLASS_NONE:
- ioprio = IOPRIO_NORM;
- /* fall through */
- case IOPRIO_CLASS_BE:
- return &cfqg->async_cfqq[1][ioprio];
- case IOPRIO_CLASS_IDLE:
- return &cfqg->async_idle_cfqq;
- default:
- BUG();
- }
-}
-
-static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
- struct bio *bio)
-{
- int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
- int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
- struct cfq_queue **async_cfqq = NULL;
- struct cfq_queue *cfqq;
- struct cfq_group *cfqg;
-
- rcu_read_lock();
- cfqg = cfq_lookup_cfqg(cfqd, __bio_blkcg(bio));
- if (!cfqg) {
- cfqq = &cfqd->oom_cfqq;
- goto out;
- }
-
- if (!is_sync) {
- if (!ioprio_valid(cic->ioprio)) {
- struct task_struct *tsk = current;
- ioprio = task_nice_ioprio(tsk);
- ioprio_class = task_nice_ioclass(tsk);
- }
- async_cfqq = cfq_async_queue_prio(cfqg, ioprio_class, ioprio);
- cfqq = *async_cfqq;
- if (cfqq)
- goto out;
- }
-
- cfqq = kmem_cache_alloc_node(cfq_pool,
- GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN,
- cfqd->queue->node);
- if (!cfqq) {
- cfqq = &cfqd->oom_cfqq;
- goto out;
- }
-
- /* cfq_init_cfqq() assumes cfqq->ioprio_class is initialized. */
- cfqq->ioprio_class = IOPRIO_CLASS_NONE;
- cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
- cfq_init_prio_data(cfqq, cic);
- cfq_link_cfqq_cfqg(cfqq, cfqg);
- cfq_log_cfqq(cfqd, cfqq, "alloced");
-
- if (async_cfqq) {
- /* a new async queue is created, pin and remember */
- cfqq->ref++;
- *async_cfqq = cfqq;
- }
-out:
- cfqq->ref++;
- rcu_read_unlock();
- return cfqq;
-}
-
-static void
-__cfq_update_io_thinktime(struct cfq_ttime *ttime, u64 slice_idle)
-{
- u64 elapsed = ktime_get_ns() - ttime->last_end_request;
- elapsed = min(elapsed, 2UL * slice_idle);
-
- ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8;
- ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8);
- ttime->ttime_mean = div64_ul(ttime->ttime_total + 128,
- ttime->ttime_samples);
-}
-
-static void
-cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_cq *cic)
-{
- if (cfq_cfqq_sync(cfqq)) {
- __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle);
- __cfq_update_io_thinktime(&cfqq->service_tree->ttime,
- cfqd->cfq_slice_idle);
- }
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle);
-#endif
-}
-
-static void
-cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *rq)
-{
- sector_t sdist = 0;
- sector_t n_sec = blk_rq_sectors(rq);
- if (cfqq->last_request_pos) {
- if (cfqq->last_request_pos < blk_rq_pos(rq))
- sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
- else
- sdist = cfqq->last_request_pos - blk_rq_pos(rq);
- }
-
- cfqq->seek_history <<= 1;
- if (blk_queue_nonrot(cfqd->queue))
- cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT);
- else
- cfqq->seek_history |= (sdist > CFQQ_SEEK_THR);
-}
-
-static inline bool req_noidle(struct request *req)
-{
- return req_op(req) == REQ_OP_WRITE &&
- (req->cmd_flags & (REQ_SYNC | REQ_IDLE)) == REQ_SYNC;
-}
-
-/*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter
- */
-static void
-cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_cq *cic)
-{
- int old_idle, enable_idle;
-
- /*
- * Don't idle for async or idle io prio class
- */
- if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
- return;
-
- enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
-
- if (cfqq->queued[0] + cfqq->queued[1] >= 4)
- cfq_mark_cfqq_deep(cfqq);
-
- if (cfqq->next_rq && req_noidle(cfqq->next_rq))
- enable_idle = 0;
- else if (!atomic_read(&cic->icq.ioc->active_ref) ||
- !cfqd->cfq_slice_idle ||
- (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
- enable_idle = 0;
- else if (sample_valid(cic->ttime.ttime_samples)) {
- if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle)
- enable_idle = 0;
- else
- enable_idle = 1;
- }
-
- if (old_idle != enable_idle) {
- cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
- if (enable_idle)
- cfq_mark_cfqq_idle_window(cfqq);
- else
- cfq_clear_cfqq_idle_window(cfqq);
- }
-}
-
-/*
- * Check if new_cfqq should preempt the currently active queue. Return 0 for
- * no or if we aren't sure, a 1 will cause a preempt.
- */
-static bool
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
- struct request *rq)
-{
- struct cfq_queue *cfqq;
-
- cfqq = cfqd->active_queue;
- if (!cfqq)
- return false;
-
- if (cfq_class_idle(new_cfqq))
- return false;
-
- if (cfq_class_idle(cfqq))
- return true;
-
- /*
- * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
- */
- if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
- return false;
-
- /*
- * if the new request is sync, but the currently running queue is
- * not, let the sync request have priority.
- */
- if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
- return true;
-
- /*
- * Treat ancestors of current cgroup the same way as current cgroup.
- * For anybody else we disallow preemption to guarantee service
- * fairness among cgroups.
- */
- if (!cfqg_is_descendant(cfqq->cfqg, new_cfqq->cfqg))
- return false;
-
- if (cfq_slice_used(cfqq))
- return true;
-
- /*
- * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
- */
- if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
- return true;
-
- WARN_ON_ONCE(cfqq->ioprio_class != new_cfqq->ioprio_class);
- /* Allow preemption only if we are idling on sync-noidle tree */
- if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD &&
- cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD &&
- RB_EMPTY_ROOT(&cfqq->sort_list))
- return true;
-
- /*
- * So both queues are sync. Let the new request get disk time if
- * it's a metadata request and the current queue is doing regular IO.
- */
- if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
- return true;
-
- /* An idle queue should not be idle now for some reason */
- if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
- return true;
-
- if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
- return false;
-
- /*
- * if this request is as-good as one we would expect from the
- * current cfqq, let it preempt
- */
- if (cfq_rq_close(cfqd, cfqq, rq))
- return true;
-
- return false;
-}
-
-/*
- * cfqq preempts the active queue. if we allowed preempt with no slice left,
- * let it have half of its nominal slice.
- */
-static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- enum wl_type_t old_type = cfqq_type(cfqd->active_queue);
-
- cfq_log_cfqq(cfqd, cfqq, "preempt");
- cfq_slice_expired(cfqd, 1);
-
- /*
- * workload type is changed, don't save slice, otherwise preempt
- * doesn't happen
- */
- if (old_type != cfqq_type(cfqq))
- cfqq->cfqg->saved_wl_slice = 0;
-
- /*
- * Put the new queue at the front of the of the current list,
- * so we know that it will be selected next.
- */
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
- cfq_service_tree_add(cfqd, cfqq, 1);
-
- cfqq->slice_end = 0;
- cfq_mark_cfqq_slice_new(cfqq);
-}
-
-/*
- * Called when a new fs request (rq) is added (to cfqq). Check if there's
- * something we should do about it
- */
-static void
-cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *rq)
-{
- struct cfq_io_cq *cic = RQ_CIC(rq);
-
- cfqd->rq_queued++;
- if (rq->cmd_flags & REQ_PRIO)
- cfqq->prio_pending++;
-
- cfq_update_io_thinktime(cfqd, cfqq, cic);
- cfq_update_io_seektime(cfqd, cfqq, rq);
- cfq_update_idle_window(cfqd, cfqq, cic);
-
- cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
-
- if (cfqq == cfqd->active_queue) {
- /*
- * Remember that we saw a request from this process, but
- * don't start queuing just yet. Otherwise we risk seeing lots
- * of tiny requests, because we disrupt the normal plugging
- * and merging. If the request is already larger than a single
- * page, let it rip immediately. For that case we assume that
- * merging is already done. Ditto for a busy system that
- * has other work pending, don't risk delaying until the
- * idle timer unplug to continue working.
- */
- if (cfq_cfqq_wait_request(cfqq)) {
- if (blk_rq_bytes(rq) > PAGE_SIZE ||
- cfqd->busy_queues > 1) {
- cfq_del_timer(cfqd, cfqq);
- cfq_clear_cfqq_wait_request(cfqq);
- __blk_run_queue(cfqd->queue);
- } else {
- cfqg_stats_update_idle_time(cfqq->cfqg);
- cfq_mark_cfqq_must_dispatch(cfqq);
- }
- }
- } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
- /*
- * not the active queue - expire current slice if it is
- * idle and has expired it's mean thinktime or this new queue
- * has some old slice time left and is of higher priority or
- * this new queue is RT and the current one is BE
- */
- cfq_preempt_queue(cfqd, cfqq);
- __blk_run_queue(cfqd->queue);
- }
-}
-
-static void cfq_insert_request(struct request_queue *q, struct request *rq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
- cfq_log_cfqq(cfqd, cfqq, "insert_request");
- cfq_init_prio_data(cfqq, RQ_CIC(rq));
-
- rq->fifo_time = ktime_get_ns() + cfqd->cfq_fifo_expire[rq_is_sync(rq)];
- list_add_tail(&rq->queuelist, &cfqq->fifo);
- cfq_add_rq_rb(rq);
- cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,
- rq->cmd_flags);
- cfq_rq_enqueued(cfqd, cfqq, rq);
-}
-
-/*
- * Update hw_tag based on peak queue depth over 50 samples under
- * sufficient load.
- */
-static void cfq_update_hw_tag(struct cfq_data *cfqd)
-{
- struct cfq_queue *cfqq = cfqd->active_queue;
-
- if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth)
- cfqd->hw_tag_est_depth = cfqd->rq_in_driver;
-
- if (cfqd->hw_tag == 1)
- return;
-
- if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
- cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
- return;
-
- /*
- * If active queue hasn't enough requests and can idle, cfq might not
- * dispatch sufficient requests to hardware. Don't zero hw_tag in this
- * case
- */
- if (cfqq && cfq_cfqq_idle_window(cfqq) &&
- cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] <
- CFQ_HW_QUEUE_MIN && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN)
- return;
-
- if (cfqd->hw_tag_samples++ < 50)
- return;
-
- if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN)
- cfqd->hw_tag = 1;
- else
- cfqd->hw_tag = 0;
-}
-
-static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- struct cfq_io_cq *cic = cfqd->active_cic;
- u64 now = ktime_get_ns();
-
- /* If the queue already has requests, don't wait */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- return false;
-
- /* If there are other queues in the group, don't wait */
- if (cfqq->cfqg->nr_cfqq > 1)
- return false;
-
- /* the only queue in the group, but think time is big */
- if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true))
- return false;
-
- if (cfq_slice_used(cfqq))
- return true;
-
- /* if slice left is less than think time, wait busy */
- if (cic && sample_valid(cic->ttime.ttime_samples)
- && (cfqq->slice_end - now < cic->ttime.ttime_mean))
- return true;
-
- /*
- * If think times is less than a jiffy than ttime_mean=0 and above
- * will not be true. It might happen that slice has not expired yet
- * but will expire soon (4-5 ns) during select_queue(). To cover the
- * case where think time is less than a jiffy, mark the queue wait
- * busy if only 1 jiffy is left in the slice.
- */
- if (cfqq->slice_end - now <= jiffies_to_nsecs(1))
- return true;
-
- return false;
-}
-
-static void cfq_completed_request(struct request_queue *q, struct request *rq)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = rq_is_sync(rq);
- u64 now = ktime_get_ns();
-
- cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", req_noidle(rq));
-
- cfq_update_hw_tag(cfqd);
-
- WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->dispatched);
- cfqd->rq_in_driver--;
- cfqq->dispatched--;
- (RQ_CFQG(rq))->dispatched--;
- cfqg_stats_update_completion(cfqq->cfqg, rq->start_time_ns,
- rq->io_start_time_ns, rq->cmd_flags);
-
- cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--;
-
- if (sync) {
- struct cfq_rb_root *st;
-
- RQ_CIC(rq)->ttime.last_end_request = now;
-
- if (cfq_cfqq_on_rr(cfqq))
- st = cfqq->service_tree;
- else
- st = st_for(cfqq->cfqg, cfqq_class(cfqq),
- cfqq_type(cfqq));
-
- st->ttime.last_end_request = now;
- if (rq->start_time_ns + cfqd->cfq_fifo_expire[1] <= now)
- cfqd->last_delayed_sync = now;
- }
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- cfqq->cfqg->ttime.last_end_request = now;
-#endif
-
- /*
- * If this is the active queue, check if it needs to be expired,
- * or if we want to idle in case it has no pending requests.
- */
- if (cfqd->active_queue == cfqq) {
- const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
-
- if (cfq_cfqq_slice_new(cfqq)) {
- cfq_set_prio_slice(cfqd, cfqq);
- cfq_clear_cfqq_slice_new(cfqq);
- }
-
- /*
- * Should we wait for next request to come in before we expire
- * the queue.
- */
- if (cfq_should_wait_busy(cfqd, cfqq)) {
- u64 extend_sl = cfqd->cfq_slice_idle;
- if (!cfqd->cfq_slice_idle)
- extend_sl = cfqd->cfq_group_idle;
- cfqq->slice_end = now + extend_sl;
- cfq_mark_cfqq_wait_busy(cfqq);
- cfq_log_cfqq(cfqd, cfqq, "will busy wait");
- }
-
- /*
- * Idling is not enabled on:
- * - expired queues
- * - idle-priority queues
- * - async queues
- * - queues with still some requests queued
- * - when there is a close cooperator
- */
- if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
- cfq_slice_expired(cfqd, 1);
- else if (sync && cfqq_empty &&
- !cfq_close_cooperator(cfqd, cfqq)) {
- cfq_arm_slice_timer(cfqd);
- }
- }
-
- if (!cfqd->rq_in_driver)
- cfq_schedule_dispatch(cfqd);
-}
-
-static void cfqq_boost_on_prio(struct cfq_queue *cfqq, unsigned int op)
-{
- /*
- * If REQ_PRIO is set, boost class and prio level, if it's below
- * BE/NORM. If prio is not set, restore the potentially boosted
- * class/prio level.
- */
- if (!(op & REQ_PRIO)) {
- cfqq->ioprio_class = cfqq->org_ioprio_class;
- cfqq->ioprio = cfqq->org_ioprio;
- } else {
- if (cfq_class_idle(cfqq))
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- if (cfqq->ioprio > IOPRIO_NORM)
- cfqq->ioprio = IOPRIO_NORM;
- }
-}
-
-static inline int __cfq_may_queue(struct cfq_queue *cfqq)
-{
- if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
- cfq_mark_cfqq_must_alloc_slice(cfqq);
- return ELV_MQUEUE_MUST;
- }
-
- return ELV_MQUEUE_MAY;
-}
-
-static int cfq_may_queue(struct request_queue *q, unsigned int op)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct task_struct *tsk = current;
- struct cfq_io_cq *cic;
- struct cfq_queue *cfqq;
-
- /*
- * don't force setup of a queue from here, as a call to may_queue
- * does not necessarily imply that a request actually will be queued.
- * so just lookup a possibly existing queue, or return 'may queue'
- * if that fails
- */
- cic = cfq_cic_lookup(cfqd, tsk->io_context);
- if (!cic)
- return ELV_MQUEUE_MAY;
-
- cfqq = cic_to_cfqq(cic, op_is_sync(op));
- if (cfqq) {
- cfq_init_prio_data(cfqq, cic);
- cfqq_boost_on_prio(cfqq, op);
-
- return __cfq_may_queue(cfqq);
- }
-
- return ELV_MQUEUE_MAY;
-}
-
-/*
- * queue lock held here
- */
-static void cfq_put_request(struct request *rq)
-{
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
-
- if (cfqq) {
- const int rw = rq_data_dir(rq);
-
- BUG_ON(!cfqq->allocated[rw]);
- cfqq->allocated[rw]--;
-
- /* Put down rq reference on cfqg */
- cfqg_put(RQ_CFQG(rq));
- rq->elv.priv[0] = NULL;
- rq->elv.priv[1] = NULL;
-
- cfq_put_queue(cfqq);
- }
-}
-
-static struct cfq_queue *
-cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic,
- struct cfq_queue *cfqq)
-{
- cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
- cic_set_cfqq(cic, cfqq->new_cfqq, 1);
- cfq_mark_cfqq_coop(cfqq->new_cfqq);
- cfq_put_queue(cfqq);
- return cic_to_cfqq(cic, 1);
-}
-
-/*
- * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
- * was the last process referring to said cfqq.
- */
-static struct cfq_queue *
-split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
-{
- if (cfqq_process_refs(cfqq) == 1) {
- cfqq->pid = current->pid;
- cfq_clear_cfqq_coop(cfqq);
- cfq_clear_cfqq_split_coop(cfqq);
- return cfqq;
- }
-
- cic_set_cfqq(cic, NULL, 1);
-
- cfq_put_cooperator(cfqq);
-
- cfq_put_queue(cfqq);
- return NULL;
-}
-/*
- * Allocate cfq data structures associated with this request.
- */
-static int
-cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio,
- gfp_t gfp_mask)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq);
- const int rw = rq_data_dir(rq);
- const bool is_sync = rq_is_sync(rq);
- struct cfq_queue *cfqq;
-
- spin_lock_irq(q->queue_lock);
-
- check_ioprio_changed(cic, bio);
- check_blkcg_changed(cic, bio);
-new_queue:
- cfqq = cic_to_cfqq(cic, is_sync);
- if (!cfqq || cfqq == &cfqd->oom_cfqq) {
- if (cfqq)
- cfq_put_queue(cfqq);
- cfqq = cfq_get_queue(cfqd, is_sync, cic, bio);
- cic_set_cfqq(cic, cfqq, is_sync);
- } else {
- /*
- * If the queue was seeky for too long, break it apart.
- */
- if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) {
- cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq");
- cfqq = split_cfqq(cic, cfqq);
- if (!cfqq)
- goto new_queue;
- }
-
- /*
- * Check to see if this queue is scheduled to merge with
- * another, closely cooperating queue. The merging of
- * queues happens here as it must be done in process context.
- * The reference on new_cfqq was taken in merge_cfqqs.
- */
- if (cfqq->new_cfqq)
- cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq);
- }
-
- cfqq->allocated[rw]++;
-
- cfqq->ref++;
- cfqg_get(cfqq->cfqg);
- rq->elv.priv[0] = cfqq;
- rq->elv.priv[1] = cfqq->cfqg;
- spin_unlock_irq(q->queue_lock);
-
- return 0;
-}
-
-static void cfq_kick_queue(struct work_struct *work)
-{
- struct cfq_data *cfqd =
- container_of(work, struct cfq_data, unplug_work);
- struct request_queue *q = cfqd->queue;
-
- spin_lock_irq(q->queue_lock);
- __blk_run_queue(cfqd->queue);
- spin_unlock_irq(q->queue_lock);
-}
-
-/*
- * Timer running if the active_queue is currently idling inside its time slice
- */
-static enum hrtimer_restart cfq_idle_slice_timer(struct hrtimer *timer)
-{
- struct cfq_data *cfqd = container_of(timer, struct cfq_data,
- idle_slice_timer);
- struct cfq_queue *cfqq;
- unsigned long flags;
- int timed_out = 1;
-
- cfq_log(cfqd, "idle timer fired");
-
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
- cfqq = cfqd->active_queue;
- if (cfqq) {
- timed_out = 0;
-
- /*
- * We saw a request before the queue expired, let it through
- */
- if (cfq_cfqq_must_dispatch(cfqq))
- goto out_kick;
-
- /*
- * expired
- */
- if (cfq_slice_used(cfqq))
- goto expire;
-
- /*
- * only expire and reinvoke request handler, if there are
- * other queues with pending requests
- */
- if (!cfqd->busy_queues)
- goto out_cont;
-
- /*
- * not expired and it has a request pending, let it dispatch
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- goto out_kick;
-
- /*
- * Queue depth flag is reset only when the idle didn't succeed
- */
- cfq_clear_cfqq_deep(cfqq);
- }
-expire:
- cfq_slice_expired(cfqd, timed_out);
-out_kick:
- cfq_schedule_dispatch(cfqd);
-out_cont:
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- return HRTIMER_NORESTART;
-}
-
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
-{
- hrtimer_cancel(&cfqd->idle_slice_timer);
- cancel_work_sync(&cfqd->unplug_work);
-}
-
-static void cfq_exit_queue(struct elevator_queue *e)
-{
- struct cfq_data *cfqd = e->elevator_data;
- struct request_queue *q = cfqd->queue;
-
- cfq_shutdown_timer_wq(cfqd);
-
- spin_lock_irq(q->queue_lock);
-
- if (cfqd->active_queue)
- __cfq_slice_expired(cfqd, cfqd->active_queue, 0);
-
- spin_unlock_irq(q->queue_lock);
-
- cfq_shutdown_timer_wq(cfqd);
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- blkcg_deactivate_policy(q, &blkcg_policy_cfq);
-#else
- kfree(cfqd->root_group);
-#endif
- kfree(cfqd);
-}
-
-static int cfq_init_queue(struct request_queue *q, struct elevator_type *e)
-{
- struct cfq_data *cfqd;
- struct blkcg_gq *blkg __maybe_unused;
- int i, ret;
- struct elevator_queue *eq;
-
- eq = elevator_alloc(q, e);
- if (!eq)
- return -ENOMEM;
-
- cfqd = kzalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
- if (!cfqd) {
- kobject_put(&eq->kobj);
- return -ENOMEM;
- }
- eq->elevator_data = cfqd;
-
- cfqd->queue = q;
- spin_lock_irq(q->queue_lock);
- q->elevator = eq;
- spin_unlock_irq(q->queue_lock);
-
- /* Init root service tree */
- cfqd->grp_service_tree = CFQ_RB_ROOT;
-
- /* Init root group and prefer root group over other groups by default */
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- ret = blkcg_activate_policy(q, &blkcg_policy_cfq);
- if (ret)
- goto out_free;
-
- cfqd->root_group = blkg_to_cfqg(q->root_blkg);
-#else
- ret = -ENOMEM;
- cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group),
- GFP_KERNEL, cfqd->queue->node);
- if (!cfqd->root_group)
- goto out_free;
-
- cfq_init_cfqg_base(cfqd->root_group);
- cfqd->root_group->weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
- cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
-#endif
-
- /*
- * Not strictly needed (since RB_ROOT just clears the node and we
- * zeroed cfqd on alloc), but better be safe in case someone decides
- * to add magic to the rb code
- */
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- cfqd->prio_trees[i] = RB_ROOT;
-
- /*
- * Our fallback cfqq if cfq_get_queue() runs into OOM issues.
- * Grab a permanent reference to it, so that the normal code flow
- * will not attempt to free it. oom_cfqq is linked to root_group
- * but shouldn't hold a reference as it'll never be unlinked. Lose
- * the reference from linking right away.
- */
- cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
- cfqd->oom_cfqq.ref++;
-
- spin_lock_irq(q->queue_lock);
- cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group);
- cfqg_put(cfqd->root_group);
- spin_unlock_irq(q->queue_lock);
-
- hrtimer_init(&cfqd->idle_slice_timer, CLOCK_MONOTONIC,
- HRTIMER_MODE_REL);
- cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-
- INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
-
- cfqd->cfq_quantum = cfq_quantum;
- cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
- cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
- cfqd->cfq_back_max = cfq_back_max;
- cfqd->cfq_back_penalty = cfq_back_penalty;
- cfqd->cfq_slice[0] = cfq_slice_async;
- cfqd->cfq_slice[1] = cfq_slice_sync;
- cfqd->cfq_target_latency = cfq_target_latency;
- cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
- cfqd->cfq_slice_idle = cfq_slice_idle;
- cfqd->cfq_group_idle = cfq_group_idle;
- cfqd->cfq_latency = 1;
- cfqd->hw_tag = -1;
- /*
- * we optimistically start assuming sync ops weren't delayed in last
- * second, in order to have larger depth for async operations.
- */
- cfqd->last_delayed_sync = ktime_get_ns() - NSEC_PER_SEC;
- return 0;
-
-out_free:
- kfree(cfqd);
- kobject_put(&eq->kobj);
- return ret;
-}
-
-static void cfq_registered_queue(struct request_queue *q)
-{
- struct elevator_queue *e = q->elevator;
- struct cfq_data *cfqd = e->elevator_data;
-
- /*
- * Default to IOPS mode with no idling for SSDs
- */
- if (blk_queue_nonrot(q))
- cfqd->cfq_slice_idle = 0;
- wbt_disable_default(q);
-}
-
-/*
- * sysfs parts below -->
- */
-static ssize_t
-cfq_var_show(unsigned int var, char *page)
-{
- return sprintf(page, "%u\n", var);
-}
-
-static void
-cfq_var_store(unsigned int *var, const char *page)
-{
- char *p = (char *) page;
-
- *var = simple_strtoul(p, &p, 10);
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
-static ssize_t __FUNC(struct elevator_queue *e, char *page) \
-{ \
- struct cfq_data *cfqd = e->elevator_data; \
- u64 __data = __VAR; \
- if (__CONV) \
- __data = div_u64(__data, NSEC_PER_MSEC); \
- return cfq_var_show(__data, (page)); \
-}
-SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
-SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
-SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
-SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0);
-SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
-SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_idle, 1);
-SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
-SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
-SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
-SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
-SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1);
-#undef SHOW_FUNCTION
-
-#define USEC_SHOW_FUNCTION(__FUNC, __VAR) \
-static ssize_t __FUNC(struct elevator_queue *e, char *page) \
-{ \
- struct cfq_data *cfqd = e->elevator_data; \
- u64 __data = __VAR; \
- __data = div_u64(__data, NSEC_PER_USEC); \
- return cfq_var_show(__data, (page)); \
-}
-USEC_SHOW_FUNCTION(cfq_slice_idle_us_show, cfqd->cfq_slice_idle);
-USEC_SHOW_FUNCTION(cfq_group_idle_us_show, cfqd->cfq_group_idle);
-USEC_SHOW_FUNCTION(cfq_slice_sync_us_show, cfqd->cfq_slice[1]);
-USEC_SHOW_FUNCTION(cfq_slice_async_us_show, cfqd->cfq_slice[0]);
-USEC_SHOW_FUNCTION(cfq_target_latency_us_show, cfqd->cfq_target_latency);
-#undef USEC_SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
-{ \
- struct cfq_data *cfqd = e->elevator_data; \
- unsigned int __data, __min = (MIN), __max = (MAX); \
- \
- cfq_var_store(&__data, (page)); \
- if (__data < __min) \
- __data = __min; \
- else if (__data > __max) \
- __data = __max; \
- if (__CONV) \
- *(__PTR) = (u64)__data * NSEC_PER_MSEC; \
- else \
- *(__PTR) = __data; \
- return count; \
-}
-STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1,
- UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1,
- UINT_MAX, 1);
-STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
-STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1,
- UINT_MAX, 0);
-STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
- UINT_MAX, 0);
-STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
-STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1);
-#undef STORE_FUNCTION
-
-#define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX) \
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
-{ \
- struct cfq_data *cfqd = e->elevator_data; \
- unsigned int __data, __min = (MIN), __max = (MAX); \
- \
- cfq_var_store(&__data, (page)); \
- if (__data < __min) \
- __data = __min; \
- else if (__data > __max) \
- __data = __max; \
- *(__PTR) = (u64)__data * NSEC_PER_USEC; \
- return count; \
-}
-USEC_STORE_FUNCTION(cfq_slice_idle_us_store, &cfqd->cfq_slice_idle, 0, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_group_idle_us_store, &cfqd->cfq_group_idle, 0, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_slice_sync_us_store, &cfqd->cfq_slice[1], 1, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_slice_async_us_store, &cfqd->cfq_slice[0], 1, UINT_MAX);
-USEC_STORE_FUNCTION(cfq_target_latency_us_store, &cfqd->cfq_target_latency, 1, UINT_MAX);
-#undef USEC_STORE_FUNCTION
-
-#define CFQ_ATTR(name) \
- __ATTR(name, 0644, cfq_##name##_show, cfq_##name##_store)
-
-static struct elv_fs_entry cfq_attrs[] = {
- CFQ_ATTR(quantum),
- CFQ_ATTR(fifo_expire_sync),
- CFQ_ATTR(fifo_expire_async),
- CFQ_ATTR(back_seek_max),
- CFQ_ATTR(back_seek_penalty),
- CFQ_ATTR(slice_sync),
- CFQ_ATTR(slice_sync_us),
- CFQ_ATTR(slice_async),
- CFQ_ATTR(slice_async_us),
- CFQ_ATTR(slice_async_rq),
- CFQ_ATTR(slice_idle),
- CFQ_ATTR(slice_idle_us),
- CFQ_ATTR(group_idle),
- CFQ_ATTR(group_idle_us),
- CFQ_ATTR(low_latency),
- CFQ_ATTR(target_latency),
- CFQ_ATTR(target_latency_us),
- __ATTR_NULL
-};
-
-static struct elevator_type iosched_cfq = {
- .ops.sq = {
- .elevator_merge_fn = cfq_merge,
- .elevator_merged_fn = cfq_merged_request,
- .elevator_merge_req_fn = cfq_merged_requests,
- .elevator_allow_bio_merge_fn = cfq_allow_bio_merge,
- .elevator_allow_rq_merge_fn = cfq_allow_rq_merge,
- .elevator_bio_merged_fn = cfq_bio_merged,
- .elevator_dispatch_fn = cfq_dispatch_requests,
- .elevator_add_req_fn = cfq_insert_request,
- .elevator_activate_req_fn = cfq_activate_request,
- .elevator_deactivate_req_fn = cfq_deactivate_request,
- .elevator_completed_req_fn = cfq_completed_request,
- .elevator_former_req_fn = elv_rb_former_request,
- .elevator_latter_req_fn = elv_rb_latter_request,
- .elevator_init_icq_fn = cfq_init_icq,
- .elevator_exit_icq_fn = cfq_exit_icq,
- .elevator_set_req_fn = cfq_set_request,
- .elevator_put_req_fn = cfq_put_request,
- .elevator_may_queue_fn = cfq_may_queue,
- .elevator_init_fn = cfq_init_queue,
- .elevator_exit_fn = cfq_exit_queue,
- .elevator_registered_fn = cfq_registered_queue,
- },
- .icq_size = sizeof(struct cfq_io_cq),
- .icq_align = __alignof__(struct cfq_io_cq),
- .elevator_attrs = cfq_attrs,
- .elevator_name = "cfq",
- .elevator_owner = THIS_MODULE,
-};
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static struct blkcg_policy blkcg_policy_cfq = {
- .dfl_cftypes = cfq_blkcg_files,
- .legacy_cftypes = cfq_blkcg_legacy_files,
-
- .cpd_alloc_fn = cfq_cpd_alloc,
- .cpd_init_fn = cfq_cpd_init,
- .cpd_free_fn = cfq_cpd_free,
- .cpd_bind_fn = cfq_cpd_bind,
-
- .pd_alloc_fn = cfq_pd_alloc,
- .pd_init_fn = cfq_pd_init,
- .pd_offline_fn = cfq_pd_offline,
- .pd_free_fn = cfq_pd_free,
- .pd_reset_stats_fn = cfq_pd_reset_stats,
-};
-#endif
-
-static int __init cfq_init(void)
-{
- int ret;
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- ret = blkcg_policy_register(&blkcg_policy_cfq);
- if (ret)
- return ret;
-#else
- cfq_group_idle = 0;
-#endif
-
- ret = -ENOMEM;
- cfq_pool = KMEM_CACHE(cfq_queue, 0);
- if (!cfq_pool)
- goto err_pol_unreg;
-
- ret = elv_register(&iosched_cfq);
- if (ret)
- goto err_free_pool;
-
- return 0;
-
-err_free_pool:
- kmem_cache_destroy(cfq_pool);
-err_pol_unreg:
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- blkcg_policy_unregister(&blkcg_policy_cfq);
-#endif
- return ret;
-}
-
-static void __exit cfq_exit(void)
-{
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- blkcg_policy_unregister(&blkcg_policy_cfq);
-#endif
- elv_unregister(&iosched_cfq);
- kmem_cache_destroy(cfq_pool);
-}
-
-module_init(cfq_init);
-module_exit(cfq_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
deleted file mode 100644
index ef2f1f09e9b3..000000000000
--- a/block/deadline-iosched.c
+++ /dev/null
@@ -1,560 +0,0 @@
-/*
- * Deadline i/o scheduler.
- *
- * Copyright (C) 2002 Jens Axboe <axboe@kernel.dk>
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/rbtree.h>
-
-/*
- * See Documentation/block/deadline-iosched.txt
- */
-static const int read_expire = HZ / 2; /* max time before a read is submitted. */
-static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
-static const int writes_starved = 2; /* max times reads can starve a write */
-static const int fifo_batch = 16; /* # of sequential requests treated as one
- by the above parameters. For throughput. */
-
-struct deadline_data {
- /*
- * run time data
- */
-
- /*
- * requests (deadline_rq s) are present on both sort_list and fifo_list
- */
- struct rb_root sort_list[2];
- struct list_head fifo_list[2];
-
- /*
- * next in sort order. read, write or both are NULL
- */
- struct request *next_rq[2];
- unsigned int batching; /* number of sequential requests made */
- unsigned int starved; /* times reads have starved writes */
-
- /*
- * settings that change how the i/o scheduler behaves
- */
- int fifo_expire[2];
- int fifo_batch;
- int writes_starved;
- int front_merges;
-};
-
-static inline struct rb_root *
-deadline_rb_root(struct deadline_data *dd, struct request *rq)
-{
- return &dd->sort_list[rq_data_dir(rq)];
-}
-
-/*
- * get the request after `rq' in sector-sorted order
- */
-static inline struct request *
-deadline_latter_request(struct request *rq)
-{
- struct rb_node *node = rb_next(&rq->rb_node);
-
- if (node)
- return rb_entry_rq(node);
-
- return NULL;
-}
-
-static void
-deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
-{
- struct rb_root *root = deadline_rb_root(dd, rq);
-
- elv_rb_add(root, rq);
-}
-
-static inline void
-deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
-{
- const int data_dir = rq_data_dir(rq);
-
- if (dd->next_rq[data_dir] == rq)
- dd->next_rq[data_dir] = deadline_latter_request(rq);
-
- elv_rb_del(deadline_rb_root(dd, rq), rq);
-}
-
-/*
- * add rq to rbtree and fifo
- */
-static void
-deadline_add_request(struct request_queue *q, struct request *rq)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- const int data_dir = rq_data_dir(rq);
-
- /*
- * This may be a requeue of a write request that has locked its
- * target zone. If it is the case, this releases the zone lock.
- */
- blk_req_zone_write_unlock(rq);
-
- deadline_add_rq_rb(dd, rq);
-
- /*
- * set expire time and add to fifo list
- */
- rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
- list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
-}
-
-/*
- * remove rq from rbtree and fifo.
- */
-static void deadline_remove_request(struct request_queue *q, struct request *rq)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
-
- rq_fifo_clear(rq);
- deadline_del_rq_rb(dd, rq);
-}
-
-static enum elv_merge
-deadline_merge(struct request_queue *q, struct request **req, struct bio *bio)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- struct request *__rq;
-
- /*
- * check for front merge
- */
- if (dd->front_merges) {
- sector_t sector = bio_end_sector(bio);
-
- __rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector);
- if (__rq) {
- BUG_ON(sector != blk_rq_pos(__rq));
-
- if (elv_bio_merge_ok(__rq, bio)) {
- *req = __rq;
- return ELEVATOR_FRONT_MERGE;
- }
- }
- }
-
- return ELEVATOR_NO_MERGE;
-}
-
-static void deadline_merged_request(struct request_queue *q,
- struct request *req, enum elv_merge type)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
-
- /*
- * if the merge was a front merge, we need to reposition request
- */
- if (type == ELEVATOR_FRONT_MERGE) {
- elv_rb_del(deadline_rb_root(dd, req), req);
- deadline_add_rq_rb(dd, req);
- }
-}
-
-static void
-deadline_merged_requests(struct request_queue *q, struct request *req,
- struct request *next)
-{
- /*
- * if next expires before rq, assign its expire time to rq
- * and move into next position (next will be deleted) in fifo
- */
- if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
- if (time_before((unsigned long)next->fifo_time,
- (unsigned long)req->fifo_time)) {
- list_move(&req->queuelist, &next->queuelist);
- req->fifo_time = next->fifo_time;
- }
- }
-
- /*
- * kill knowledge of next, this one is a goner
- */
- deadline_remove_request(q, next);
-}
-
-/*
- * move request from sort list to dispatch queue.
- */
-static inline void
-deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
-{
- struct request_queue *q = rq->q;
-
- /*
- * For a zoned block device, write requests must write lock their
- * target zone.
- */
- blk_req_zone_write_lock(rq);
-
- deadline_remove_request(q, rq);
- elv_dispatch_add_tail(q, rq);
-}
-
-/*
- * move an entry to dispatch queue
- */
-static void
-deadline_move_request(struct deadline_data *dd, struct request *rq)
-{
- const int data_dir = rq_data_dir(rq);
-
- dd->next_rq[READ] = NULL;
- dd->next_rq[WRITE] = NULL;
- dd->next_rq[data_dir] = deadline_latter_request(rq);
-
- /*
- * take it off the sort and fifo list, move
- * to dispatch queue
- */
- deadline_move_to_dispatch(dd, rq);
-}
-
-/*
- * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
- * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
- */
-static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
-{
- struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);
-
- /*
- * rq is expired!
- */
- if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
- return 1;
-
- return 0;
-}
-
-/*
- * For the specified data direction, return the next request to dispatch using
- * arrival ordered lists.
- */
-static struct request *
-deadline_fifo_request(struct deadline_data *dd, int data_dir)
-{
- struct request *rq;
-
- if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
- return NULL;
-
- if (list_empty(&dd->fifo_list[data_dir]))
- return NULL;
-
- rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
- if (data_dir == READ || !blk_queue_is_zoned(rq->q))
- return rq;
-
- /*
- * Look for a write request that can be dispatched, that is one with
- * an unlocked target zone.
- */
- list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) {
- if (blk_req_can_dispatch_to_zone(rq))
- return rq;
- }
-
- return NULL;
-}
-
-/*
- * For the specified data direction, return the next request to dispatch using
- * sector position sorted lists.
- */
-static struct request *
-deadline_next_request(struct deadline_data *dd, int data_dir)
-{
- struct request *rq;
-
- if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
- return NULL;
-
- rq = dd->next_rq[data_dir];
- if (!rq)
- return NULL;
-
- if (data_dir == READ || !blk_queue_is_zoned(rq->q))
- return rq;
-
- /*
- * Look for a write request that can be dispatched, that is one with
- * an unlocked target zone.
- */
- while (rq) {
- if (blk_req_can_dispatch_to_zone(rq))
- return rq;
- rq = deadline_latter_request(rq);
- }
-
- return NULL;
-}
-
-/*
- * deadline_dispatch_requests selects the best request according to
- * read/write expire, fifo_batch, etc
- */
-static int deadline_dispatch_requests(struct request_queue *q, int force)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- const int reads = !list_empty(&dd->fifo_list[READ]);
- const int writes = !list_empty(&dd->fifo_list[WRITE]);
- struct request *rq, *next_rq;
- int data_dir;
-
- /*
- * batches are currently reads XOR writes
- */
- rq = deadline_next_request(dd, WRITE);
- if (!rq)
- rq = deadline_next_request(dd, READ);
-
- if (rq && dd->batching < dd->fifo_batch)
- /* we have a next request are still entitled to batch */
- goto dispatch_request;
-
- /*
- * at this point we are not running a batch. select the appropriate
- * data direction (read / write)
- */
-
- if (reads) {
- BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
-
- if (deadline_fifo_request(dd, WRITE) &&
- (dd->starved++ >= dd->writes_starved))
- goto dispatch_writes;
-
- data_dir = READ;
-
- goto dispatch_find_request;
- }
-
- /*
- * there are either no reads or writes have been starved
- */
-
- if (writes) {
-dispatch_writes:
- BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));
-
- dd->starved = 0;
-
- data_dir = WRITE;
-
- goto dispatch_find_request;
- }
-
- return 0;
-
-dispatch_find_request:
- /*
- * we are not running a batch, find best request for selected data_dir
- */
- next_rq = deadline_next_request(dd, data_dir);
- if (deadline_check_fifo(dd, data_dir) || !next_rq) {
- /*
- * A deadline has expired, the last request was in the other
- * direction, or we have run out of higher-sectored requests.
- * Start again from the request with the earliest expiry time.
- */
- rq = deadline_fifo_request(dd, data_dir);
- } else {
- /*
- * The last req was the same dir and we have a next request in
- * sort order. No expired requests so continue on from here.
- */
- rq = next_rq;
- }
-
- /*
- * For a zoned block device, if we only have writes queued and none of
- * them can be dispatched, rq will be NULL.
- */
- if (!rq)
- return 0;
-
- dd->batching = 0;
-
-dispatch_request:
- /*
- * rq is the selected appropriate request.
- */
- dd->batching++;
- deadline_move_request(dd, rq);
-
- return 1;
-}
-
-/*
- * For zoned block devices, write unlock the target zone of completed
- * write requests.
- */
-static void
-deadline_completed_request(struct request_queue *q, struct request *rq)
-{
- blk_req_zone_write_unlock(rq);
-}
-
-static void deadline_exit_queue(struct elevator_queue *e)
-{
- struct deadline_data *dd = e->elevator_data;
-
- BUG_ON(!list_empty(&dd->fifo_list[READ]));
- BUG_ON(!list_empty(&dd->fifo_list[WRITE]));
-
- kfree(dd);
-}
-
-/*
- * initialize elevator private data (deadline_data).
- */
-static int deadline_init_queue(struct request_queue *q, struct elevator_type *e)
-{
- struct deadline_data *dd;
- struct elevator_queue *eq;
-
- eq = elevator_alloc(q, e);
- if (!eq)
- return -ENOMEM;
-
- dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
- if (!dd) {
- kobject_put(&eq->kobj);
- return -ENOMEM;
- }
- eq->elevator_data = dd;
-
- INIT_LIST_HEAD(&dd->fifo_list[READ]);
- INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
- dd->sort_list[READ] = RB_ROOT;
- dd->sort_list[WRITE] = RB_ROOT;
- dd->fifo_expire[READ] = read_expire;
- dd->fifo_expire[WRITE] = write_expire;
- dd->writes_starved = writes_starved;
- dd->front_merges = 1;
- dd->fifo_batch = fifo_batch;
-
- spin_lock_irq(q->queue_lock);
- q->elevator = eq;
- spin_unlock_irq(q->queue_lock);
- return 0;
-}
-
-/*
- * sysfs parts below
- */
-
-static ssize_t
-deadline_var_show(int var, char *page)
-{
- return sprintf(page, "%d\n", var);
-}
-
-static void
-deadline_var_store(int *var, const char *page)
-{
- char *p = (char *) page;
-
- *var = simple_strtol(p, &p, 10);
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
-static ssize_t __FUNC(struct elevator_queue *e, char *page) \
-{ \
- struct deadline_data *dd = e->elevator_data; \
- int __data = __VAR; \
- if (__CONV) \
- __data = jiffies_to_msecs(__data); \
- return deadline_var_show(__data, (page)); \
-}
-SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1);
-SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1);
-SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
-SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
-SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
-static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
-{ \
- struct deadline_data *dd = e->elevator_data; \
- int __data; \
- deadline_var_store(&__data, (page)); \
- if (__data < (MIN)) \
- __data = (MIN); \
- else if (__data > (MAX)) \
- __data = (MAX); \
- if (__CONV) \
- *(__PTR) = msecs_to_jiffies(__data); \
- else \
- *(__PTR) = __data; \
- return count; \
-}
-STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
-STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
-STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
-#undef STORE_FUNCTION
-
-#define DD_ATTR(name) \
- __ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)
-
-static struct elv_fs_entry deadline_attrs[] = {
- DD_ATTR(read_expire),
- DD_ATTR(write_expire),
- DD_ATTR(writes_starved),
- DD_ATTR(front_merges),
- DD_ATTR(fifo_batch),
- __ATTR_NULL
-};
-
-static struct elevator_type iosched_deadline = {
- .ops.sq = {
- .elevator_merge_fn = deadline_merge,
- .elevator_merged_fn = deadline_merged_request,
- .elevator_merge_req_fn = deadline_merged_requests,
- .elevator_dispatch_fn = deadline_dispatch_requests,
- .elevator_completed_req_fn = deadline_completed_request,
- .elevator_add_req_fn = deadline_add_request,
- .elevator_former_req_fn = elv_rb_former_request,
- .elevator_latter_req_fn = elv_rb_latter_request,
- .elevator_init_fn = deadline_init_queue,
- .elevator_exit_fn = deadline_exit_queue,
- },
-
- .elevator_attrs = deadline_attrs,
- .elevator_name = "deadline",
- .elevator_owner = THIS_MODULE,
-};
-
-static int __init deadline_init(void)
-{
- return elv_register(&iosched_deadline);
-}
-
-static void __exit deadline_exit(void)
-{
- elv_unregister(&iosched_deadline);
-}
-
-module_init(deadline_init);
-module_exit(deadline_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("deadline IO scheduler");
diff --git a/block/elevator.c b/block/elevator.c
index 8fdcd64ae12e..54e1adac26c5 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -225,8 +225,6 @@ int elevator_init(struct request_queue *q)
chosen_elevator);
}

- if (!e)
- e = elevator_get(q, CONFIG_DEFAULT_IOSCHED, false);
if (!e) {
printk(KERN_ERR
"Default I/O scheduler not found. Using noop.\n");
@@ -356,68 +354,6 @@ struct request *elv_rb_find(struct rb_root *root, sector_t sector)
}
EXPORT_SYMBOL(elv_rb_find);

-/*
- * Insert rq into dispatch queue of q. Queue lock must be held on
- * entry. rq is sort instead into the dispatch queue. To be used by
- * specific elevators.
- */
-void elv_dispatch_sort(struct request_queue *q, struct request *rq)
-{
- sector_t boundary;
- struct list_head *entry;
-
- if (q->last_merge == rq)
- q->last_merge = NULL;
-
- elv_rqhash_del(q, rq);
-
- q->nr_sorted--;
-
- boundary = q->end_sector;
- list_for_each_prev(entry, &q->queue_head) {
- struct request *pos = list_entry_rq(entry);
-
- if (req_op(rq) != req_op(pos))
- break;
- if (rq_data_dir(rq) != rq_data_dir(pos))
- break;
- if (pos->rq_flags & (RQF_STARTED | RQF_SOFTBARRIER))
- break;
- if (blk_rq_pos(rq) >= boundary) {
- if (blk_rq_pos(pos) < boundary)
- continue;
- } else {
- if (blk_rq_pos(pos) >= boundary)
- break;
- }
- if (blk_rq_pos(rq) >= blk_rq_pos(pos))
- break;
- }
-
- list_add(&rq->queuelist, entry);
-}
-EXPORT_SYMBOL(elv_dispatch_sort);
-
-/*
- * Insert rq into dispatch queue of q. Queue lock must be held on
- * entry. rq is added to the back of the dispatch queue. To be used by
- * specific elevators.
- */
-void elv_dispatch_add_tail(struct request_queue *q, struct request *rq)
-{
- if (q->last_merge == rq)
- q->last_merge = NULL;
-
- elv_rqhash_del(q, rq);
-
- q->nr_sorted--;
-
- q->end_sector = rq_end_sector(rq);
- q->boundary_rq = rq;
- list_add_tail(&rq->queuelist, &q->queue_head);
-}
-EXPORT_SYMBOL(elv_dispatch_add_tail);
-
enum elv_merge elv_merge(struct request_queue *q, struct request **req,
struct bio *bio)
{
@@ -881,12 +817,6 @@ int elv_register(struct elevator_type *e)
list_add_tail(&e->list, &elv_list);
spin_unlock(&elv_list_lock);

- /* print pretty message */
- if (elevator_match(e, chosen_elevator) ||
- (!*chosen_elevator &&
- elevator_match(e, CONFIG_DEFAULT_IOSCHED)))
- def = " (default)";
-
printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
def);
return 0;
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
deleted file mode 100644
index 2d1b15d89b45..000000000000
--- a/block/noop-iosched.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * elevator noop
- */
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-
-struct noop_data {
- struct list_head queue;
-};
-
-static void noop_merged_requests(struct request_queue *q, struct request *rq,
- struct request *next)
-{
- list_del_init(&next->queuelist);
-}
-
-static int noop_dispatch(struct request_queue *q, int force)
-{
- struct noop_data *nd = q->elevator->elevator_data;
- struct request *rq;
-
- rq = list_first_entry_or_null(&nd->queue, struct request, queuelist);
- if (rq) {
- list_del_init(&rq->queuelist);
- elv_dispatch_sort(q, rq);
- return 1;
- }
- return 0;
-}
-
-static void noop_add_request(struct request_queue *q, struct request *rq)
-{
- struct noop_data *nd = q->elevator->elevator_data;
-
- list_add_tail(&rq->queuelist, &nd->queue);
-}
-
-static struct request *
-noop_former_request(struct request_queue *q, struct request *rq)
-{
- struct noop_data *nd = q->elevator->elevator_data;
-
- if (rq->queuelist.prev == &nd->queue)
- return NULL;
- return list_prev_entry(rq, queuelist);
-}
-
-static struct request *
-noop_latter_request(struct request_queue *q, struct request *rq)
-{
- struct noop_data *nd = q->elevator->elevator_data;
-
- if (rq->queuelist.next == &nd->queue)
- return NULL;
- return list_next_entry(rq, queuelist);
-}
-
-static int noop_init_queue(struct request_queue *q, struct elevator_type *e)
-{
- struct noop_data *nd;
- struct elevator_queue *eq;
-
- eq = elevator_alloc(q, e);
- if (!eq)
- return -ENOMEM;
-
- nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
- if (!nd) {
- kobject_put(&eq->kobj);
- return -ENOMEM;
- }
- eq->elevator_data = nd;
-
- INIT_LIST_HEAD(&nd->queue);
-
- spin_lock_irq(q->queue_lock);
- q->elevator = eq;
- spin_unlock_irq(q->queue_lock);
- return 0;
-}
-
-static void noop_exit_queue(struct elevator_queue *e)
-{
- struct noop_data *nd = e->elevator_data;
-
- BUG_ON(!list_empty(&nd->queue));
- kfree(nd);
-}
-
-static struct elevator_type elevator_noop = {
- .ops.sq = {
- .elevator_merge_req_fn = noop_merged_requests,
- .elevator_dispatch_fn = noop_dispatch,
- .elevator_add_req_fn = noop_add_request,
- .elevator_former_req_fn = noop_former_request,
- .elevator_latter_req_fn = noop_latter_request,
- .elevator_init_fn = noop_init_queue,
- .elevator_exit_fn = noop_exit_queue,
- },
- .elevator_name = "noop",
- .elevator_owner = THIS_MODULE,
-};
-
-static int __init noop_init(void)
-{
- return elv_register(&elevator_noop);
-}
-
-static void __exit noop_exit(void)
-{
- elv_unregister(&elevator_noop);
-}
-
-module_init(noop_init);
-module_exit(noop_exit);
-
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("No-op IO scheduler");
--
2.17.1