806 lines
31 KiB
C
806 lines
31 KiB
C
/*
|
|
* BFQ-v7r8 for 3.10.8+: data structures and common functions prototypes.
|
|
*
|
|
* Based on ideas and code from CFQ:
|
|
* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
|
|
*
|
|
* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
|
|
* Paolo Valente <paolo.valente@unimore.it>
|
|
*
|
|
* Copyright (C) 2010 Paolo Valente <paolo.valente@unimore.it>
|
|
*/
|
|
|
|
#ifndef _BFQ_H
|
|
#define _BFQ_H
|
|
|
|
#include <linux/blktrace_api.h>
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/ioprio.h>
|
|
#include <linux/rbtree.h>
|
|
|
|
#define BFQ_IOPRIO_CLASSES 3
|
|
#define BFQ_CL_IDLE_TIMEOUT (HZ/5)
|
|
|
|
#define BFQ_MIN_WEIGHT 1
|
|
#define BFQ_MAX_WEIGHT 1000
|
|
|
|
#define BFQ_DEFAULT_QUEUE_IOPRIO 4
|
|
|
|
#define BFQ_DEFAULT_GRP_WEIGHT 10
|
|
#define BFQ_DEFAULT_GRP_IOPRIO 0
|
|
#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
|
|
|
|
struct bfq_entity;
|
|
|
|
/**
|
|
* struct bfq_service_tree - per ioprio_class service tree.
|
|
* @active: tree for active entities (i.e., those backlogged).
|
|
* @idle: tree for idle entities (i.e., those not backlogged, with V <= F_i).
|
|
* @first_idle: idle entity with minimum F_i.
|
|
* @last_idle: idle entity with maximum F_i.
|
|
* @vtime: scheduler virtual time.
|
|
* @wsum: scheduler weight sum; active and idle entities contribute to it.
|
|
*
|
|
* Each service tree represents a B-WF2Q+ scheduler on its own. Each
|
|
* ioprio_class has its own independent scheduler, and so its own
|
|
* bfq_service_tree. All the fields are protected by the queue lock
|
|
* of the containing bfqd.
|
|
*/
|
|
struct bfq_service_tree {
|
|
struct rb_root active;
|
|
struct rb_root idle;
|
|
|
|
struct bfq_entity *first_idle;
|
|
struct bfq_entity *last_idle;
|
|
|
|
u64 vtime;
|
|
unsigned long wsum;
|
|
};
|
|
|
|
/**
|
|
* struct bfq_sched_data - multi-class scheduler.
|
|
* @in_service_entity: entity in service.
|
|
* @next_in_service: head-of-the-line entity in the scheduler.
|
|
* @service_tree: array of service trees, one per ioprio_class.
|
|
*
|
|
* bfq_sched_data is the basic scheduler queue. It supports three
|
|
* ioprio_classes, and can be used either as a toplevel queue or as
|
|
* an intermediate queue on a hierarchical setup.
|
|
* @next_in_service points to the active entity of the sched_data
|
|
* service trees that will be scheduled next.
|
|
*
|
|
* The supported ioprio_classes are the same as in CFQ, in descending
|
|
* priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
|
|
* Requests from higher priority queues are served before all the
|
|
* requests from lower priority queues; among requests of the same
|
|
* queue requests are served according to B-WF2Q+.
|
|
* All the fields are protected by the queue lock of the containing bfqd.
|
|
*/
|
|
struct bfq_sched_data {
|
|
struct bfq_entity *in_service_entity;
|
|
struct bfq_entity *next_in_service;
|
|
struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
|
|
};
|
|
|
|
/**
|
|
* struct bfq_weight_counter - counter of the number of all active entities
|
|
* with a given weight.
|
|
* @weight: weight of the entities that this counter refers to.
|
|
* @num_active: number of active entities with this weight.
|
|
* @weights_node: weights tree member (see bfq_data's @queue_weights_tree
|
|
* and @group_weights_tree).
|
|
*/
|
|
struct bfq_weight_counter {
|
|
short int weight;
|
|
unsigned int num_active;
|
|
struct rb_node weights_node;
|
|
};
|
|
|
|
/**
|
|
* struct bfq_entity - schedulable entity.
|
|
* @rb_node: service_tree member.
|
|
* @weight_counter: pointer to the weight counter associated with this entity.
|
|
* @on_st: flag, true if the entity is on a tree (either the active or
|
|
* the idle one of its service_tree).
|
|
* @finish: B-WF2Q+ finish timestamp (aka F_i).
|
|
* @start: B-WF2Q+ start timestamp (aka S_i).
|
|
* @tree: tree the entity is enqueued into; %NULL if not on a tree.
|
|
* @min_start: minimum start time of the (active) subtree rooted at
|
|
* this entity; used for O(log N) lookups into active trees.
|
|
* @service: service received during the last round of service.
|
|
* @budget: budget used to calculate F_i; F_i = S_i + @budget / @weight.
|
|
* @weight: weight of the queue
|
|
* @parent: parent entity, for hierarchical scheduling.
|
|
* @my_sched_data: for non-leaf nodes in the cgroup hierarchy, the
|
|
* associated scheduler queue, %NULL on leaf nodes.
|
|
* @sched_data: the scheduler queue this entity belongs to.
|
|
* @ioprio: the ioprio in use.
|
|
* @new_weight: when a weight change is requested, the new weight value.
|
|
* @orig_weight: original weight, used to implement weight boosting
|
|
* @new_ioprio: when an ioprio change is requested, the new ioprio value.
|
|
* @ioprio_class: the ioprio_class in use.
|
|
* @new_ioprio_class: when an ioprio_class change is requested, the new
|
|
* ioprio_class value.
|
|
* @ioprio_changed: flag, true when the user requested a weight, ioprio or
|
|
* ioprio_class change.
|
|
*
|
|
* A bfq_entity is used to represent either a bfq_queue (leaf node in the
|
|
* cgroup hierarchy) or a bfq_group into the upper level scheduler. Each
|
|
* entity belongs to the sched_data of the parent group in the cgroup
|
|
* hierarchy. Non-leaf entities have also their own sched_data, stored
|
|
* in @my_sched_data.
|
|
*
|
|
* Each entity stores independently its priority values; this would
|
|
* allow different weights on different devices, but this
|
|
* functionality is not exported to userspace by now. Priorities and
|
|
* weights are updated lazily, first storing the new values into the
|
|
* new_* fields, then setting the @ioprio_changed flag. As soon as
|
|
* there is a transition in the entity state that allows the priority
|
|
* update to take place the effective and the requested priority
|
|
* values are synchronized.
|
|
*
|
|
* Unless cgroups are used, the weight value is calculated from the
|
|
* ioprio to export the same interface as CFQ. When dealing with
|
|
* ``well-behaved'' queues (i.e., queues that do not spend too much
|
|
* time to consume their budget and have true sequential behavior, and
|
|
* when there are no external factors breaking anticipation) the
|
|
* relative weights at each level of the cgroups hierarchy should be
|
|
* guaranteed. All the fields are protected by the queue lock of the
|
|
* containing bfqd.
|
|
*/
|
|
struct bfq_entity {
|
|
struct rb_node rb_node;
|
|
struct bfq_weight_counter *weight_counter;
|
|
|
|
int on_st;
|
|
|
|
u64 finish;
|
|
u64 start;
|
|
|
|
struct rb_root *tree;
|
|
|
|
u64 min_start;
|
|
|
|
unsigned long service, budget;
|
|
unsigned short weight, new_weight;
|
|
unsigned short orig_weight;
|
|
|
|
struct bfq_entity *parent;
|
|
|
|
struct bfq_sched_data *my_sched_data;
|
|
struct bfq_sched_data *sched_data;
|
|
|
|
unsigned short ioprio, new_ioprio;
|
|
unsigned short ioprio_class, new_ioprio_class;
|
|
|
|
int ioprio_changed;
|
|
};
|
|
|
|
struct bfq_group;
|
|
|
|
/**
|
|
* struct bfq_queue - leaf schedulable entity.
|
|
* @ref: reference counter.
|
|
* @bfqd: parent bfq_data.
|
|
* @new_bfqq: shared bfq_queue if queue is cooperating with
|
|
* one or more other queues.
|
|
* @pos_node: request-position tree member (see bfq_data's @rq_pos_tree).
|
|
* @pos_root: request-position tree root (see bfq_data's @rq_pos_tree).
|
|
* @sort_list: sorted list of pending requests.
|
|
* @next_rq: if fifo isn't expired, next request to serve.
|
|
* @queued: nr of requests queued in @sort_list.
|
|
* @allocated: currently allocated requests.
|
|
* @meta_pending: pending metadata requests.
|
|
* @fifo: fifo list of requests in sort_list.
|
|
* @entity: entity representing this queue in the scheduler.
|
|
* @max_budget: maximum budget allowed from the feedback mechanism.
|
|
* @budget_timeout: budget expiration (in jiffies).
|
|
* @dispatched: number of requests on the dispatch list or inside driver.
|
|
* @flags: status flags.
|
|
* @bfqq_list: node for active/idle bfqq list inside our bfqd.
|
|
* @burst_list_node: node for the device's burst list.
|
|
* @seek_samples: number of seeks sampled
|
|
* @seek_total: sum of the distances of the seeks sampled
|
|
* @seek_mean: mean seek distance
|
|
* @last_request_pos: position of the last request enqueued
|
|
* @requests_within_timer: number of consecutive pairs of request completion
|
|
* and arrival, such that the queue becomes idle
|
|
* after the completion, but the next request arrives
|
|
* within an idle time slice; used only if the queue's
|
|
* IO_bound has been cleared.
|
|
* @pid: pid of the process owning the queue, used for logging purposes.
|
|
* @last_wr_start_finish: start time of the current weight-raising period if
|
|
* the @bfq-queue is being weight-raised, otherwise
|
|
* finish time of the last weight-raising period
|
|
* @wr_cur_max_time: current max raising time for this queue
|
|
* @soft_rt_next_start: minimum time instant such that, only if a new
|
|
* request is enqueued after this time instant in an
|
|
* idle @bfq_queue with no outstanding requests, then
|
|
* the task associated with the queue it is deemed as
|
|
* soft real-time (see the comments to the function
|
|
* bfq_bfqq_softrt_next_start())
|
|
* @last_idle_bklogged: time of the last transition of the @bfq_queue from
|
|
* idle to backlogged
|
|
* @service_from_backlogged: cumulative service received from the @bfq_queue
|
|
* since the last transition from idle to
|
|
* backlogged
|
|
* @bic: pointer to the bfq_io_cq owning the bfq_queue, set to %NULL if the
|
|
* queue is shared
|
|
*
|
|
* A bfq_queue is a leaf request queue; it can be associated with an
|
|
* io_context or more, if it is async or shared between cooperating
|
|
* processes. @cgroup holds a reference to the cgroup, to be sure that it
|
|
* does not disappear while a bfqq still references it (mostly to avoid
|
|
* races between request issuing and task migration followed by cgroup
|
|
* destruction).
|
|
* All the fields are protected by the queue lock of the containing bfqd.
|
|
*/
|
|
struct bfq_queue {
|
|
atomic_t ref;
|
|
struct bfq_data *bfqd;
|
|
|
|
/* fields for cooperating queues handling */
|
|
struct bfq_queue *new_bfqq;
|
|
struct rb_node pos_node;
|
|
struct rb_root *pos_root;
|
|
|
|
struct rb_root sort_list;
|
|
struct request *next_rq;
|
|
int queued[2];
|
|
int allocated[2];
|
|
int meta_pending;
|
|
struct list_head fifo;
|
|
|
|
struct bfq_entity entity;
|
|
|
|
unsigned long max_budget;
|
|
unsigned long budget_timeout;
|
|
|
|
int dispatched;
|
|
|
|
unsigned int flags;
|
|
|
|
struct list_head bfqq_list;
|
|
|
|
struct hlist_node burst_list_node;
|
|
|
|
unsigned int seek_samples;
|
|
u64 seek_total;
|
|
sector_t seek_mean;
|
|
sector_t last_request_pos;
|
|
|
|
unsigned int requests_within_timer;
|
|
|
|
pid_t pid;
|
|
struct bfq_io_cq *bic;
|
|
|
|
/* weight-raising fields */
|
|
unsigned long wr_cur_max_time;
|
|
unsigned long soft_rt_next_start;
|
|
unsigned long last_wr_start_finish;
|
|
unsigned int wr_coeff;
|
|
unsigned long last_idle_bklogged;
|
|
unsigned long service_from_backlogged;
|
|
};
|
|
|
|
/**
|
|
* struct bfq_ttime - per process thinktime stats.
|
|
* @ttime_total: total process thinktime
|
|
* @ttime_samples: number of thinktime samples
|
|
* @ttime_mean: average process thinktime
|
|
*/
|
|
struct bfq_ttime {
|
|
unsigned long last_end_request;
|
|
|
|
unsigned long ttime_total;
|
|
unsigned long ttime_samples;
|
|
unsigned long ttime_mean;
|
|
};
|
|
|
|
/**
|
|
* struct bfq_io_cq - per (request_queue, io_context) structure.
|
|
* @icq: associated io_cq structure
|
|
* @bfqq: array of two process queues, the sync and the async
|
|
* @ttime: associated @bfq_ttime struct
|
|
* @wr_time_left: snapshot of the time left before weight raising ends
|
|
* for the sync queue associated to this process; this
|
|
* snapshot is taken to remember this value while the weight
|
|
* raising is suspended because the queue is merged with a
|
|
* shared queue, and is used to set @raising_cur_max_time
|
|
* when the queue is split from the shared queue and its
|
|
* weight is raised again
|
|
* @saved_idle_window: same purpose as the previous field for the idle
|
|
* window
|
|
* @saved_IO_bound: same purpose as the previous two fields for the I/O
|
|
* bound classification of a queue
|
|
* @saved_in_large_burst: same purpose as the previous fields for the
|
|
* value of the field keeping the queue's belonging
|
|
* to a large burst
|
|
* @was_in_burst_list: true if the queue belonged to a burst list
|
|
* before its merge with another cooperating queue
|
|
* @cooperations: counter of consecutive successful queue merges underwent
|
|
* by any of the process' @bfq_queues
|
|
* @failed_cooperations: counter of consecutive failed queue merges of any
|
|
* of the process' @bfq_queues
|
|
*/
|
|
struct bfq_io_cq {
|
|
struct io_cq icq; /* must be the first member */
|
|
struct bfq_queue *bfqq[2];
|
|
struct bfq_ttime ttime;
|
|
int ioprio;
|
|
|
|
unsigned int wr_time_left;
|
|
bool saved_idle_window;
|
|
bool saved_IO_bound;
|
|
|
|
bool saved_in_large_burst;
|
|
bool was_in_burst_list;
|
|
|
|
unsigned int cooperations;
|
|
unsigned int failed_cooperations;
|
|
};
|
|
|
|
enum bfq_device_speed {
|
|
BFQ_BFQD_FAST,
|
|
BFQ_BFQD_SLOW,
|
|
};
|
|
|
|
/**
|
|
* struct bfq_data - per device data structure.
|
|
* @queue: request queue for the managed device.
|
|
* @root_group: root bfq_group for the device.
|
|
* @rq_pos_tree: rbtree sorted by next_request position, used when
|
|
* determining if two or more queues have interleaving
|
|
* requests (see bfq_close_cooperator()).
|
|
* @active_numerous_groups: number of bfq_groups containing more than one
|
|
* active @bfq_entity.
|
|
* @queue_weights_tree: rbtree of weight counters of @bfq_queues, sorted by
|
|
* weight. Used to keep track of whether all @bfq_queues
|
|
* have the same weight. The tree contains one counter
|
|
* for each distinct weight associated to some active
|
|
* and not weight-raised @bfq_queue (see the comments to
|
|
* the functions bfq_weights_tree_[add|remove] for
|
|
* further details).
|
|
* @group_weights_tree: rbtree of non-queue @bfq_entity weight counters, sorted
|
|
* by weight. Used to keep track of whether all
|
|
* @bfq_groups have the same weight. The tree contains
|
|
* one counter for each distinct weight associated to
|
|
* some active @bfq_group (see the comments to the
|
|
* functions bfq_weights_tree_[add|remove] for further
|
|
* details).
|
|
* @busy_queues: number of bfq_queues containing requests (including the
|
|
* queue in service, even if it is idling).
|
|
* @busy_in_flight_queues: number of @bfq_queues containing pending or
|
|
* in-flight requests, plus the @bfq_queue in
|
|
* service, even if idle but waiting for the
|
|
* possible arrival of its next sync request. This
|
|
* field is updated only if the device is rotational,
|
|
* but used only if the device is also NCQ-capable.
|
|
* The reason why the field is updated also for non-
|
|
* NCQ-capable rotational devices is related to the
|
|
* fact that the value of @hw_tag may be set also
|
|
* later than when busy_in_flight_queues may need to
|
|
* be incremented for the first time(s). Taking also
|
|
* this possibility into account, to avoid unbalanced
|
|
* increments/decrements, would imply more overhead
|
|
* than just updating busy_in_flight_queues
|
|
* regardless of the value of @hw_tag.
|
|
* @const_seeky_busy_in_flight_queues: number of constantly-seeky @bfq_queues
|
|
* (that is, seeky queues that expired
|
|
* for budget timeout at least once)
|
|
* containing pending or in-flight
|
|
* requests, including the in-service
|
|
* @bfq_queue if constantly seeky. This
|
|
* field is updated only if the device
|
|
* is rotational, but used only if the
|
|
* device is also NCQ-capable (see the
|
|
* comments to @busy_in_flight_queues).
|
|
* @wr_busy_queues: number of weight-raised busy @bfq_queues.
|
|
* @queued: number of queued requests.
|
|
* @rq_in_driver: number of requests dispatched and waiting for completion.
|
|
* @sync_flight: number of sync requests in the driver.
|
|
* @max_rq_in_driver: max number of reqs in driver in the last
|
|
* @hw_tag_samples completed requests.
|
|
* @hw_tag_samples: nr of samples used to calculate hw_tag.
|
|
* @hw_tag: flag set to one if the driver is showing a queueing behavior.
|
|
* @budgets_assigned: number of budgets assigned.
|
|
* @idle_slice_timer: timer set when idling for the next sequential request
|
|
* from the queue in service.
|
|
* @unplug_work: delayed work to restart dispatching on the request queue.
|
|
* @in_service_queue: bfq_queue in service.
|
|
* @in_service_bic: bfq_io_cq (bic) associated with the @in_service_queue.
|
|
* @last_position: on-disk position of the last served request.
|
|
* @last_budget_start: beginning of the last budget.
|
|
* @last_idling_start: beginning of the last idle slice.
|
|
* @peak_rate: peak transfer rate observed for a budget.
|
|
* @peak_rate_samples: number of samples used to calculate @peak_rate.
|
|
* @bfq_max_budget: maximum budget allotted to a bfq_queue before
|
|
* rescheduling.
|
|
* @group_list: list of all the bfq_groups active on the device.
|
|
* @active_list: list of all the bfq_queues active on the device.
|
|
* @idle_list: list of all the bfq_queues idle on the device.
|
|
* @bfq_fifo_expire: timeout for async/sync requests; when it expires
|
|
* requests are served in fifo order.
|
|
* @bfq_back_penalty: weight of backward seeks wrt forward ones.
|
|
* @bfq_back_max: maximum allowed backward seek.
|
|
* @bfq_slice_idle: maximum idling time.
|
|
* @bfq_user_max_budget: user-configured max budget value
|
|
* (0 for auto-tuning).
|
|
* @bfq_max_budget_async_rq: maximum budget (in nr of requests) allotted to
|
|
* async queues.
|
|
* @bfq_timeout: timeout for bfq_queues to consume their budget; used to
|
|
* to prevent seeky queues to impose long latencies to well
|
|
* behaved ones (this also implies that seeky queues cannot
|
|
* receive guarantees in the service domain; after a timeout
|
|
* they are charged for the whole allocated budget, to try
|
|
* to preserve a behavior reasonably fair among them, but
|
|
* without service-domain guarantees).
|
|
* @bfq_coop_thresh: number of queue merges after which a @bfq_queue is
|
|
* no more granted any weight-raising.
|
|
* @bfq_failed_cooperations: number of consecutive failed cooperation
|
|
* chances after which weight-raising is restored
|
|
* to a queue subject to more than bfq_coop_thresh
|
|
* queue merges.
|
|
* @bfq_requests_within_timer: number of consecutive requests that must be
|
|
* issued within the idle time slice to set
|
|
* again idling to a queue which was marked as
|
|
* non-I/O-bound (see the definition of the
|
|
* IO_bound flag for further details).
|
|
* @last_ins_in_burst: last time at which a queue entered the current
|
|
* burst of queues being activated shortly after
|
|
* each other; for more details about this and the
|
|
* following parameters related to a burst of
|
|
* activations, see the comments to the function
|
|
* @bfq_handle_burst.
|
|
* @bfq_burst_interval: reference time interval used to decide whether a
|
|
* queue has been activated shortly after
|
|
* @last_ins_in_burst.
|
|
* @burst_size: number of queues in the current burst of queue activations.
|
|
* @bfq_large_burst_thresh: maximum burst size above which the current
|
|
* queue-activation burst is deemed as 'large'.
|
|
* @large_burst: true if a large queue-activation burst is in progress.
|
|
* @burst_list: head of the burst list (as for the above fields, more details
|
|
* in the comments to the function bfq_handle_burst).
|
|
* @low_latency: if set to true, low-latency heuristics are enabled.
|
|
* @bfq_wr_coeff: maximum factor by which the weight of a weight-raised
|
|
* queue is multiplied.
|
|
* @bfq_wr_max_time: maximum duration of a weight-raising period (jiffies).
|
|
* @bfq_wr_rt_max_time: maximum duration for soft real-time processes.
|
|
* @bfq_wr_min_idle_time: minimum idle period after which weight-raising
|
|
* may be reactivated for a queue (in jiffies).
|
|
* @bfq_wr_min_inter_arr_async: minimum period between request arrivals
|
|
* after which weight-raising may be
|
|
* reactivated for an already busy queue
|
|
* (in jiffies).
|
|
* @bfq_wr_max_softrt_rate: max service-rate for a soft real-time queue,
|
|
* sectors per seconds.
|
|
* @RT_prod: cached value of the product R*T used for computing the maximum
|
|
* duration of the weight raising automatically.
|
|
* @device_speed: device-speed class for the low-latency heuristic.
|
|
* @oom_bfqq: fallback dummy bfqq for extreme OOM conditions.
|
|
*
|
|
* All the fields are protected by the @queue lock.
|
|
*/
|
|
struct bfq_data {
|
|
struct request_queue *queue;
|
|
|
|
struct bfq_group *root_group;
|
|
struct rb_root rq_pos_tree;
|
|
|
|
#ifdef CONFIG_CGROUP_BFQIO
|
|
int active_numerous_groups;
|
|
#endif
|
|
|
|
struct rb_root queue_weights_tree;
|
|
struct rb_root group_weights_tree;
|
|
|
|
int busy_queues;
|
|
int busy_in_flight_queues;
|
|
int const_seeky_busy_in_flight_queues;
|
|
int wr_busy_queues;
|
|
int queued;
|
|
int rq_in_driver;
|
|
int sync_flight;
|
|
|
|
int max_rq_in_driver;
|
|
int hw_tag_samples;
|
|
int hw_tag;
|
|
|
|
int budgets_assigned;
|
|
|
|
struct timer_list idle_slice_timer;
|
|
struct work_struct unplug_work;
|
|
|
|
struct bfq_queue *in_service_queue;
|
|
struct bfq_io_cq *in_service_bic;
|
|
|
|
sector_t last_position;
|
|
|
|
ktime_t last_budget_start;
|
|
ktime_t last_idling_start;
|
|
int peak_rate_samples;
|
|
u64 peak_rate;
|
|
unsigned long bfq_max_budget;
|
|
|
|
struct hlist_head group_list;
|
|
struct list_head active_list;
|
|
struct list_head idle_list;
|
|
|
|
unsigned int bfq_fifo_expire[2];
|
|
unsigned int bfq_back_penalty;
|
|
unsigned int bfq_back_max;
|
|
unsigned int bfq_slice_idle;
|
|
u64 bfq_class_idle_last_service;
|
|
|
|
unsigned int bfq_user_max_budget;
|
|
unsigned int bfq_max_budget_async_rq;
|
|
unsigned int bfq_timeout[2];
|
|
|
|
unsigned int bfq_coop_thresh;
|
|
unsigned int bfq_failed_cooperations;
|
|
unsigned int bfq_requests_within_timer;
|
|
|
|
unsigned long last_ins_in_burst;
|
|
unsigned long bfq_burst_interval;
|
|
int burst_size;
|
|
unsigned long bfq_large_burst_thresh;
|
|
bool large_burst;
|
|
struct hlist_head burst_list;
|
|
|
|
bool low_latency;
|
|
|
|
/* parameters of the low_latency heuristics */
|
|
unsigned int bfq_wr_coeff;
|
|
unsigned int bfq_wr_max_time;
|
|
unsigned int bfq_wr_rt_max_time;
|
|
unsigned int bfq_wr_min_idle_time;
|
|
unsigned long bfq_wr_min_inter_arr_async;
|
|
unsigned int bfq_wr_max_softrt_rate;
|
|
u64 RT_prod;
|
|
enum bfq_device_speed device_speed;
|
|
|
|
struct bfq_queue oom_bfqq;
|
|
};
|
|
|
|
enum bfqq_state_flags {
|
|
BFQ_BFQQ_FLAG_busy = 0, /* has requests or is in service */
|
|
BFQ_BFQQ_FLAG_wait_request, /* waiting for a request */
|
|
BFQ_BFQQ_FLAG_must_alloc, /* must be allowed rq alloc */
|
|
BFQ_BFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
|
|
BFQ_BFQQ_FLAG_idle_window, /* slice idling enabled */
|
|
BFQ_BFQQ_FLAG_sync, /* synchronous queue */
|
|
BFQ_BFQQ_FLAG_budget_new, /* no completion with this budget */
|
|
BFQ_BFQQ_FLAG_IO_bound, /*
|
|
* bfqq has timed-out at least once
|
|
* having consumed at most 2/10 of
|
|
* its budget
|
|
*/
|
|
BFQ_BFQQ_FLAG_in_large_burst, /*
|
|
* bfqq activated in a large burst,
|
|
* see comments to bfq_handle_burst.
|
|
*/
|
|
BFQ_BFQQ_FLAG_constantly_seeky, /*
|
|
* bfqq has proved to be slow and
|
|
* seeky until budget timeout
|
|
*/
|
|
BFQ_BFQQ_FLAG_softrt_update, /*
|
|
* may need softrt-next-start
|
|
* update
|
|
*/
|
|
BFQ_BFQQ_FLAG_coop, /* bfqq is shared */
|
|
BFQ_BFQQ_FLAG_split_coop, /* shared bfqq will be split */
|
|
BFQ_BFQQ_FLAG_just_split, /* queue has just been split */
|
|
};
|
|
|
|
#define BFQ_BFQQ_FNS(name) \
|
|
static inline void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \
|
|
{ \
|
|
(bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \
|
|
} \
|
|
static inline void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \
|
|
{ \
|
|
(bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \
|
|
} \
|
|
static inline int bfq_bfqq_##name(const struct bfq_queue *bfqq) \
|
|
{ \
|
|
return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \
|
|
}
|
|
|
|
BFQ_BFQQ_FNS(busy);
|
|
BFQ_BFQQ_FNS(wait_request);
|
|
BFQ_BFQQ_FNS(must_alloc);
|
|
BFQ_BFQQ_FNS(fifo_expire);
|
|
BFQ_BFQQ_FNS(idle_window);
|
|
BFQ_BFQQ_FNS(sync);
|
|
BFQ_BFQQ_FNS(budget_new);
|
|
BFQ_BFQQ_FNS(IO_bound);
|
|
BFQ_BFQQ_FNS(in_large_burst);
|
|
BFQ_BFQQ_FNS(constantly_seeky);
|
|
BFQ_BFQQ_FNS(coop);
|
|
BFQ_BFQQ_FNS(split_coop);
|
|
BFQ_BFQQ_FNS(just_split);
|
|
BFQ_BFQQ_FNS(softrt_update);
|
|
#undef BFQ_BFQQ_FNS
|
|
|
|
/* Logging facilities. */
|
|
#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
|
|
blk_add_trace_msg((bfqd)->queue, "bfq%d " fmt, (bfqq)->pid, ##args)
|
|
|
|
#define bfq_log(bfqd, fmt, args...) \
|
|
blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
|
|
|
|
/* Expiration reasons. */
|
|
enum bfqq_expiration {
|
|
BFQ_BFQQ_TOO_IDLE = 0, /*
|
|
* queue has been idling for
|
|
* too long
|
|
*/
|
|
BFQ_BFQQ_BUDGET_TIMEOUT, /* budget took too long to be used */
|
|
BFQ_BFQQ_BUDGET_EXHAUSTED, /* budget consumed */
|
|
BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */
|
|
};
|
|
|
|
#ifdef CONFIG_CGROUP_BFQIO
|
|
/**
|
|
* struct bfq_group - per (device, cgroup) data structure.
|
|
* @entity: schedulable entity to insert into the parent group sched_data.
|
|
* @sched_data: own sched_data, to contain child entities (they may be
|
|
* both bfq_queues and bfq_groups).
|
|
* @group_node: node to be inserted into the bfqio_cgroup->group_data
|
|
* list of the containing cgroup's bfqio_cgroup.
|
|
* @bfqd_node: node to be inserted into the @bfqd->group_list list
|
|
* of the groups active on the same device; used for cleanup.
|
|
* @bfqd: the bfq_data for the device this group acts upon.
|
|
* @async_bfqq: array of async queues for all the tasks belonging to
|
|
* the group, one queue per ioprio value per ioprio_class,
|
|
* except for the idle class that has only one queue.
|
|
* @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
|
|
* @my_entity: pointer to @entity, %NULL for the toplevel group; used
|
|
* to avoid too many special cases during group creation/
|
|
* migration.
|
|
* @active_entities: number of active entities belonging to the group;
|
|
* unused for the root group. Used to know whether there
|
|
* are groups with more than one active @bfq_entity
|
|
* (see the comments to the function
|
|
* bfq_bfqq_must_not_expire()).
|
|
*
|
|
* Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
|
|
* there is a set of bfq_groups, each one collecting the lower-level
|
|
* entities belonging to the group that are acting on the same device.
|
|
*
|
|
* Locking works as follows:
|
|
* o @group_node is protected by the bfqio_cgroup lock, and is accessed
|
|
* via RCU from its readers.
|
|
* o @bfqd is protected by the queue lock, RCU is used to access it
|
|
* from the readers.
|
|
* o All the other fields are protected by the @bfqd queue lock.
|
|
*/
|
|
struct bfq_group {
|
|
struct bfq_entity entity;
|
|
struct bfq_sched_data sched_data;
|
|
|
|
struct hlist_node group_node;
|
|
struct hlist_node bfqd_node;
|
|
|
|
void *bfqd;
|
|
|
|
struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
|
|
struct bfq_queue *async_idle_bfqq;
|
|
|
|
struct bfq_entity *my_entity;
|
|
|
|
int active_entities;
|
|
};
|
|
|
|
/**
|
|
* struct bfqio_cgroup - bfq cgroup data structure.
|
|
* @css: subsystem state for bfq in the containing cgroup.
|
|
* @weight: cgroup weight.
|
|
* @ioprio: cgroup ioprio.
|
|
* @ioprio_class: cgroup ioprio_class.
|
|
* @lock: spinlock that protects @ioprio, @ioprio_class and @group_data.
|
|
* @group_data: list containing the bfq_group belonging to this cgroup.
|
|
*
|
|
* @group_data is accessed using RCU, with @lock protecting the updates,
|
|
* @ioprio and @ioprio_class are protected by @lock.
|
|
*/
|
|
struct bfqio_cgroup {
|
|
struct cgroup_subsys_state css;
|
|
|
|
unsigned short weight, ioprio, ioprio_class;
|
|
|
|
spinlock_t lock;
|
|
struct hlist_head group_data;
|
|
};
|
|
#else
|
|
struct bfq_group {
|
|
struct bfq_sched_data sched_data;
|
|
|
|
struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
|
|
struct bfq_queue *async_idle_bfqq;
|
|
};
|
|
#endif
|
|
|
|
static inline struct bfq_service_tree *
|
|
bfq_entity_service_tree(struct bfq_entity *entity)
|
|
{
|
|
struct bfq_sched_data *sched_data = entity->sched_data;
|
|
unsigned int idx = entity->ioprio_class - 1;
|
|
|
|
BUG_ON(idx >= BFQ_IOPRIO_CLASSES);
|
|
BUG_ON(sched_data == NULL);
|
|
|
|
return sched_data->service_tree + idx;
|
|
}
|
|
|
|
static inline struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic,
|
|
bool is_sync)
|
|
{
|
|
return bic->bfqq[is_sync];
|
|
}
|
|
|
|
static inline void bic_set_bfqq(struct bfq_io_cq *bic,
|
|
struct bfq_queue *bfqq, bool is_sync)
|
|
{
|
|
bic->bfqq[is_sync] = bfqq;
|
|
}
|
|
|
|
static inline struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic)
|
|
{
|
|
return bic->icq.q->elevator->elevator_data;
|
|
}
|
|
|
|
/**
|
|
* bfq_get_bfqd_locked - get a lock to a bfqd using a RCU protected pointer.
|
|
* @ptr: a pointer to a bfqd.
|
|
* @flags: storage for the flags to be saved.
|
|
*
|
|
* This function allows bfqg->bfqd to be protected by the
|
|
* queue lock of the bfqd they reference; the pointer is dereferenced
|
|
* under RCU, so the storage for bfqd is assured to be safe as long
|
|
* as the RCU read side critical section does not end. After the
|
|
* bfqd->queue->queue_lock is taken the pointer is rechecked, to be
|
|
* sure that no other writer accessed it. If we raced with a writer,
|
|
* the function returns NULL, with the queue unlocked, otherwise it
|
|
* returns the dereferenced pointer, with the queue locked.
|
|
*/
|
|
static inline struct bfq_data *bfq_get_bfqd_locked(void **ptr,
|
|
unsigned long *flags)
|
|
{
|
|
struct bfq_data *bfqd;
|
|
|
|
rcu_read_lock();
|
|
bfqd = rcu_dereference(*(struct bfq_data **)ptr);
|
|
|
|
if (bfqd != NULL) {
|
|
spin_lock_irqsave(bfqd->queue->queue_lock, *flags);
|
|
if (*ptr == bfqd)
|
|
goto out;
|
|
spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags);
|
|
}
|
|
|
|
bfqd = NULL;
|
|
out:
|
|
rcu_read_unlock();
|
|
return bfqd;
|
|
}
|
|
|
|
static inline void bfq_put_bfqd_unlock(struct bfq_data *bfqd,
|
|
unsigned long *flags)
|
|
{
|
|
spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags);
|
|
}
|
|
|
|
static void bfq_check_ioprio_change(struct bfq_io_cq *bic);
|
|
static void bfq_put_queue(struct bfq_queue *bfqq);
|
|
static void bfq_dispatch_insert(struct request_queue *q, struct request *rq);
|
|
static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd,
|
|
struct bfq_group *bfqg, int is_sync,
|
|
struct bfq_io_cq *bic, gfp_t gfp_mask);
|
|
static void bfq_end_wr_async_queues(struct bfq_data *bfqd,
|
|
struct bfq_group *bfqg);
|
|
static void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
|
|
static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
|
|
|
|
#endif /* _BFQ_H */
|