diff options
| -rw-r--r-- | Documentation/block/cfq-iosched.txt | 291 | ||||
| -rw-r--r-- | block/Kconfig.iosched | 61 | ||||
| -rw-r--r-- | block/Makefile | 3 | ||||
| -rw-r--r-- | block/cfq-iosched.c | 4916 | ||||
| -rw-r--r-- | block/deadline-iosched.c | 560 | ||||
| -rw-r--r-- | block/elevator.c | 70 | ||||
| -rw-r--r-- | block/noop-iosched.c | 124 |
7 files changed, 0 insertions, 6025 deletions
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 ed41aa978c4a..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"); |