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1127 lines
37 KiB
1127 lines
37 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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* Header file for the BFQ I/O scheduler: data structures and |
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* prototypes of interface functions among BFQ components. |
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*/ |
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#ifndef _BFQ_H |
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#define _BFQ_H |
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#include <linux/blktrace_api.h> |
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#include <linux/hrtimer.h> |
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#include <linux/blk-cgroup.h> |
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#include "blk-cgroup-rwstat.h" |
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#define BFQ_IOPRIO_CLASSES 3 |
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#define BFQ_CL_IDLE_TIMEOUT (HZ/5) |
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#define BFQ_MIN_WEIGHT 1 |
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#define BFQ_MAX_WEIGHT 1000 |
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#define BFQ_WEIGHT_CONVERSION_COEFF 10 |
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#define BFQ_DEFAULT_QUEUE_IOPRIO 4 |
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#define BFQ_WEIGHT_LEGACY_DFL 100 |
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#define BFQ_DEFAULT_GRP_IOPRIO 0 |
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#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE |
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#define MAX_PID_STR_LENGTH 12 |
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/* |
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* Soft real-time applications are extremely more latency sensitive |
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* than interactive ones. Over-raise the weight of the former to |
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* privilege them against the latter. |
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*/ |
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#define BFQ_SOFTRT_WEIGHT_FACTOR 100 |
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struct bfq_entity; |
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/** |
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* struct bfq_service_tree - per ioprio_class service tree. |
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* |
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* Each service tree represents a B-WF2Q+ scheduler on its own. Each |
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* ioprio_class has its own independent scheduler, and so its own |
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* bfq_service_tree. All the fields are protected by the queue lock |
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* of the containing bfqd. |
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*/ |
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struct bfq_service_tree { |
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/* tree for active entities (i.e., those backlogged) */ |
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struct rb_root active; |
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/* tree for idle entities (i.e., not backlogged, with V < F_i)*/ |
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struct rb_root idle; |
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/* idle entity with minimum F_i */ |
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struct bfq_entity *first_idle; |
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/* idle entity with maximum F_i */ |
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struct bfq_entity *last_idle; |
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/* scheduler virtual time */ |
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u64 vtime; |
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/* scheduler weight sum; active and idle entities contribute to it */ |
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unsigned long wsum; |
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}; |
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/** |
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* struct bfq_sched_data - multi-class scheduler. |
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* |
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* bfq_sched_data is the basic scheduler queue. It supports three |
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* ioprio_classes, and can be used either as a toplevel queue or as an |
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* intermediate queue in a hierarchical setup. |
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* |
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* The supported ioprio_classes are the same as in CFQ, in descending |
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* priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE. |
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* Requests from higher priority queues are served before all the |
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* requests from lower priority queues; among requests of the same |
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* queue requests are served according to B-WF2Q+. |
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* |
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* The schedule is implemented by the service trees, plus the field |
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* @next_in_service, which points to the entity on the active trees |
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* that will be served next, if 1) no changes in the schedule occurs |
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* before the current in-service entity is expired, 2) the in-service |
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* queue becomes idle when it expires, and 3) if the entity pointed by |
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* in_service_entity is not a queue, then the in-service child entity |
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* of the entity pointed by in_service_entity becomes idle on |
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* expiration. This peculiar definition allows for the following |
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* optimization, not yet exploited: while a given entity is still in |
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* service, we already know which is the best candidate for next |
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* service among the other active entities in the same parent |
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* entity. We can then quickly compare the timestamps of the |
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* in-service entity with those of such best candidate. |
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* |
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* All fields are protected by the lock of the containing bfqd. |
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*/ |
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struct bfq_sched_data { |
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/* entity in service */ |
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struct bfq_entity *in_service_entity; |
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/* head-of-line entity (see comments above) */ |
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struct bfq_entity *next_in_service; |
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/* array of service trees, one per ioprio_class */ |
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struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES]; |
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/* last time CLASS_IDLE was served */ |
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unsigned long bfq_class_idle_last_service; |
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}; |
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/** |
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* struct bfq_weight_counter - counter of the number of all active queues |
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* with a given weight. |
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*/ |
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struct bfq_weight_counter { |
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unsigned int weight; /* weight of the queues this counter refers to */ |
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unsigned int num_active; /* nr of active queues with this weight */ |
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/* |
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* Weights tree member (see bfq_data's @queue_weights_tree) |
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*/ |
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struct rb_node weights_node; |
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}; |
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/** |
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* struct bfq_entity - schedulable entity. |
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* |
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* A bfq_entity is used to represent either a bfq_queue (leaf node in the |
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* cgroup hierarchy) or a bfq_group into the upper level scheduler. Each |
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* entity belongs to the sched_data of the parent group in the cgroup |
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* hierarchy. Non-leaf entities have also their own sched_data, stored |
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* in @my_sched_data. |
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* |
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* Each entity stores independently its priority values; this would |
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* allow different weights on different devices, but this |
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* functionality is not exported to userspace by now. Priorities and |
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* weights are updated lazily, first storing the new values into the |
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* new_* fields, then setting the @prio_changed flag. As soon as |
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* there is a transition in the entity state that allows the priority |
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* update to take place the effective and the requested priority |
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* values are synchronized. |
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* |
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* Unless cgroups are used, the weight value is calculated from the |
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* ioprio to export the same interface as CFQ. When dealing with |
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* "well-behaved" queues (i.e., queues that do not spend too much |
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* time to consume their budget and have true sequential behavior, and |
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* when there are no external factors breaking anticipation) the |
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* relative weights at each level of the cgroups hierarchy should be |
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* guaranteed. All the fields are protected by the queue lock of the |
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* containing bfqd. |
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*/ |
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struct bfq_entity { |
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/* service_tree member */ |
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struct rb_node rb_node; |
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/* |
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* Flag, true if the entity is on a tree (either the active or |
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* the idle one of its service_tree) or is in service. |
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*/ |
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bool on_st_or_in_serv; |
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/* B-WF2Q+ start and finish timestamps [sectors/weight] */ |
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u64 start, finish; |
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/* tree the entity is enqueued into; %NULL if not on a tree */ |
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struct rb_root *tree; |
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/* |
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* minimum start time of the (active) subtree rooted at this |
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* entity; used for O(log N) lookups into active trees |
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*/ |
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u64 min_start; |
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/* amount of service received during the last service slot */ |
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int service; |
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/* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ |
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int budget; |
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/* device weight, if non-zero, it overrides the default weight of |
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* bfq_group_data */ |
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int dev_weight; |
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/* weight of the queue */ |
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int weight; |
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/* next weight if a change is in progress */ |
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int new_weight; |
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/* original weight, used to implement weight boosting */ |
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int orig_weight; |
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/* parent entity, for hierarchical scheduling */ |
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struct bfq_entity *parent; |
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/* |
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* For non-leaf nodes in the hierarchy, the associated |
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* scheduler queue, %NULL on leaf nodes. |
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*/ |
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struct bfq_sched_data *my_sched_data; |
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/* the scheduler queue this entity belongs to */ |
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struct bfq_sched_data *sched_data; |
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/* flag, set to request a weight, ioprio or ioprio_class change */ |
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int prio_changed; |
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/* flag, set if the entity is counted in groups_with_pending_reqs */ |
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bool in_groups_with_pending_reqs; |
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/* last child queue of entity created (for non-leaf entities) */ |
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struct bfq_queue *last_bfqq_created; |
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}; |
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struct bfq_group; |
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/** |
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* struct bfq_ttime - per process thinktime stats. |
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*/ |
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struct bfq_ttime { |
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/* completion time of the last request */ |
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u64 last_end_request; |
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/* total process thinktime */ |
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u64 ttime_total; |
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/* number of thinktime samples */ |
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unsigned long ttime_samples; |
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/* average process thinktime */ |
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u64 ttime_mean; |
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}; |
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/** |
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* struct bfq_queue - leaf schedulable entity. |
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* |
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* A bfq_queue is a leaf request queue; it can be associated with an |
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* io_context or more, if it is async or shared between cooperating |
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* processes. @cgroup holds a reference to the cgroup, to be sure that it |
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* does not disappear while a bfqq still references it (mostly to avoid |
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* races between request issuing and task migration followed by cgroup |
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* destruction). |
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* All the fields are protected by the queue lock of the containing bfqd. |
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*/ |
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struct bfq_queue { |
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/* reference counter */ |
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int ref; |
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/* counter of references from other queues for delayed stable merge */ |
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int stable_ref; |
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/* parent bfq_data */ |
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struct bfq_data *bfqd; |
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/* current ioprio and ioprio class */ |
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unsigned short ioprio, ioprio_class; |
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/* next ioprio and ioprio class if a change is in progress */ |
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unsigned short new_ioprio, new_ioprio_class; |
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/* last total-service-time sample, see bfq_update_inject_limit() */ |
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u64 last_serv_time_ns; |
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/* limit for request injection */ |
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unsigned int inject_limit; |
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/* last time the inject limit has been decreased, in jiffies */ |
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unsigned long decrease_time_jif; |
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/* |
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* Shared bfq_queue if queue is cooperating with one or more |
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* other queues. |
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*/ |
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struct bfq_queue *new_bfqq; |
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/* request-position tree member (see bfq_group's @rq_pos_tree) */ |
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struct rb_node pos_node; |
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/* request-position tree root (see bfq_group's @rq_pos_tree) */ |
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struct rb_root *pos_root; |
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/* sorted list of pending requests */ |
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struct rb_root sort_list; |
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/* if fifo isn't expired, next request to serve */ |
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struct request *next_rq; |
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/* number of sync and async requests queued */ |
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int queued[2]; |
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/* number of requests currently allocated */ |
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int allocated; |
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/* number of pending metadata requests */ |
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int meta_pending; |
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/* fifo list of requests in sort_list */ |
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struct list_head fifo; |
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/* entity representing this queue in the scheduler */ |
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struct bfq_entity entity; |
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/* pointer to the weight counter associated with this entity */ |
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struct bfq_weight_counter *weight_counter; |
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/* maximum budget allowed from the feedback mechanism */ |
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int max_budget; |
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/* budget expiration (in jiffies) */ |
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unsigned long budget_timeout; |
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/* number of requests on the dispatch list or inside driver */ |
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int dispatched; |
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/* status flags */ |
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unsigned long flags; |
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/* node for active/idle bfqq list inside parent bfqd */ |
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struct list_head bfqq_list; |
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/* associated @bfq_ttime struct */ |
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struct bfq_ttime ttime; |
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/* when bfqq started to do I/O within the last observation window */ |
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u64 io_start_time; |
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/* how long bfqq has remained empty during the last observ. window */ |
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u64 tot_idle_time; |
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/* bit vector: a 1 for each seeky requests in history */ |
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u32 seek_history; |
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/* node for the device's burst list */ |
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struct hlist_node burst_list_node; |
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/* position of the last request enqueued */ |
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sector_t last_request_pos; |
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/* Number of consecutive pairs of request completion and |
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* arrival, such that the queue becomes idle after the |
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* completion, but the next request arrives within an idle |
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* time slice; used only if the queue's IO_bound flag has been |
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* cleared. |
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*/ |
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unsigned int requests_within_timer; |
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/* pid of the process owning the queue, used for logging purposes */ |
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pid_t pid; |
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/* |
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* Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL |
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* if the queue is shared. |
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*/ |
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struct bfq_io_cq *bic; |
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/* current maximum weight-raising time for this queue */ |
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unsigned long wr_cur_max_time; |
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/* |
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* Minimum time instant such that, only if a new request is |
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* enqueued after this time instant in an idle @bfq_queue with |
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* no outstanding requests, then the task associated with the |
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* queue it is deemed as soft real-time (see the comments on |
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* the function bfq_bfqq_softrt_next_start()) |
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*/ |
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unsigned long soft_rt_next_start; |
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/* |
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* Start time of the current weight-raising period if |
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* the @bfq-queue is being weight-raised, otherwise |
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* finish time of the last weight-raising period. |
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*/ |
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unsigned long last_wr_start_finish; |
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/* factor by which the weight of this queue is multiplied */ |
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unsigned int wr_coeff; |
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/* |
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* Time of the last transition of the @bfq_queue from idle to |
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* backlogged. |
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*/ |
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unsigned long last_idle_bklogged; |
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/* |
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* Cumulative service received from the @bfq_queue since the |
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* last transition from idle to backlogged. |
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*/ |
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unsigned long service_from_backlogged; |
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/* |
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* Cumulative service received from the @bfq_queue since its |
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* last transition to weight-raised state. |
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*/ |
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unsigned long service_from_wr; |
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/* |
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* Value of wr start time when switching to soft rt |
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*/ |
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unsigned long wr_start_at_switch_to_srt; |
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unsigned long split_time; /* time of last split */ |
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unsigned long first_IO_time; /* time of first I/O for this queue */ |
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unsigned long creation_time; /* when this queue is created */ |
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/* max service rate measured so far */ |
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u32 max_service_rate; |
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/* |
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* Pointer to the waker queue for this queue, i.e., to the |
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* queue Q such that this queue happens to get new I/O right |
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* after some I/O request of Q is completed. For details, see |
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* the comments on the choice of the queue for injection in |
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* bfq_select_queue(). |
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*/ |
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struct bfq_queue *waker_bfqq; |
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/* pointer to the curr. tentative waker queue, see bfq_check_waker() */ |
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struct bfq_queue *tentative_waker_bfqq; |
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/* number of times the same tentative waker has been detected */ |
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unsigned int num_waker_detections; |
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/* node for woken_list, see below */ |
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struct hlist_node woken_list_node; |
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/* |
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* Head of the list of the woken queues for this queue, i.e., |
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* of the list of the queues for which this queue is a waker |
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* queue. This list is used to reset the waker_bfqq pointer in |
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* the woken queues when this queue exits. |
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*/ |
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struct hlist_head woken_list; |
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}; |
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/** |
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* struct bfq_io_cq - per (request_queue, io_context) structure. |
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*/ |
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struct bfq_io_cq { |
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/* associated io_cq structure */ |
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struct io_cq icq; /* must be the first member */ |
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/* array of two process queues, the sync and the async */ |
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struct bfq_queue *bfqq[2]; |
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/* per (request_queue, blkcg) ioprio */ |
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int ioprio; |
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#ifdef CONFIG_BFQ_GROUP_IOSCHED |
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uint64_t blkcg_serial_nr; /* the current blkcg serial */ |
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#endif |
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/* |
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* Snapshot of the has_short_time flag before merging; taken |
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* to remember its value while the queue is merged, so as to |
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* be able to restore it in case of split. |
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*/ |
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bool saved_has_short_ttime; |
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/* |
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* Same purpose as the previous two fields for the I/O bound |
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* classification of a queue. |
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*/ |
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bool saved_IO_bound; |
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u64 saved_io_start_time; |
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u64 saved_tot_idle_time; |
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/* |
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* Same purpose as the previous fields for the value of the |
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* field keeping the queue's belonging to a large burst |
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*/ |
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bool saved_in_large_burst; |
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/* |
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* True if the queue belonged to a burst list before its merge |
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* with another cooperating queue. |
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*/ |
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bool was_in_burst_list; |
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/* |
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* Save the weight when a merge occurs, to be able |
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* to restore it in case of split. If the weight is not |
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* correctly resumed when the queue is recycled, |
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* then the weight of the recycled queue could differ |
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* from the weight of the original queue. |
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*/ |
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unsigned int saved_weight; |
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/* |
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* Similar to previous fields: save wr information. |
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*/ |
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unsigned long saved_wr_coeff; |
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unsigned long saved_last_wr_start_finish; |
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unsigned long saved_service_from_wr; |
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unsigned long saved_wr_start_at_switch_to_srt; |
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unsigned int saved_wr_cur_max_time; |
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struct bfq_ttime saved_ttime; |
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/* Save also injection state */ |
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u64 saved_last_serv_time_ns; |
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unsigned int saved_inject_limit; |
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unsigned long saved_decrease_time_jif; |
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/* candidate queue for a stable merge (due to close creation time) */ |
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struct bfq_queue *stable_merge_bfqq; |
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bool stably_merged; /* non splittable if true */ |
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}; |
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/** |
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* struct bfq_data - per-device data structure. |
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* |
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* All the fields are protected by @lock. |
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*/ |
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struct bfq_data { |
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/* device request queue */ |
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struct request_queue *queue; |
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/* dispatch queue */ |
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struct list_head dispatch; |
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/* root bfq_group for the device */ |
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struct bfq_group *root_group; |
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/* |
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* rbtree of weight counters of @bfq_queues, sorted by |
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* weight. Used to keep track of whether all @bfq_queues have |
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* the same weight. The tree contains one counter for each |
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* distinct weight associated to some active and not |
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* weight-raised @bfq_queue (see the comments to the functions |
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* bfq_weights_tree_[add|remove] for further details). |
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*/ |
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struct rb_root_cached queue_weights_tree; |
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|
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/* |
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* Number of groups with at least one descendant process that |
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* has at least one request waiting for completion. Note that |
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* this accounts for also requests already dispatched, but not |
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* yet completed. Therefore this number of groups may differ |
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* (be larger) than the number of active groups, as a group is |
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* considered active only if its corresponding entity has |
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* descendant queues with at least one request queued. This |
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* number is used to decide whether a scenario is symmetric. |
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* For a detailed explanation see comments on the computation |
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* of the variable asymmetric_scenario in the function |
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* bfq_better_to_idle(). |
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* |
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* However, it is hard to compute this number exactly, for |
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* groups with multiple descendant processes. Consider a group |
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* that is inactive, i.e., that has no descendant process with |
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* pending I/O inside BFQ queues. Then suppose that |
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* num_groups_with_pending_reqs is still accounting for this |
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* group, because the group has descendant processes with some |
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* I/O request still in flight. num_groups_with_pending_reqs |
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* should be decremented when the in-flight request of the |
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* last descendant process is finally completed (assuming that |
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* nothing else has changed for the group in the meantime, in |
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* terms of composition of the group and active/inactive state of child |
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* groups and processes). To accomplish this, an additional |
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* pending-request counter must be added to entities, and must |
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* be updated correctly. To avoid this additional field and operations, |
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* we resort to the following tradeoff between simplicity and |
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* accuracy: for an inactive group that is still counted in |
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* num_groups_with_pending_reqs, we decrement |
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* num_groups_with_pending_reqs when the first descendant |
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* process of the group remains with no request waiting for |
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* completion. |
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* |
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* Even this simpler decrement strategy requires a little |
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* carefulness: to avoid multiple decrements, we flag a group, |
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* more precisely an entity representing a group, as still |
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* counted in num_groups_with_pending_reqs when it becomes |
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* inactive. Then, when the first descendant queue of the |
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* entity remains with no request waiting for completion, |
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* num_groups_with_pending_reqs is decremented, and this flag |
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* is reset. After this flag is reset for the entity, |
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* num_groups_with_pending_reqs won't be decremented any |
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* longer in case a new descendant queue of the entity remains |
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* with no request waiting for completion. |
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*/ |
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unsigned int num_groups_with_pending_reqs; |
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|
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/* |
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* Per-class (RT, BE, IDLE) number of bfq_queues containing |
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* requests (including the queue in service, even if it is |
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* idling). |
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*/ |
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unsigned int busy_queues[3]; |
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/* number of weight-raised busy @bfq_queues */ |
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int wr_busy_queues; |
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/* number of queued requests */ |
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int queued; |
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/* number of requests dispatched and waiting for completion */ |
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int rq_in_driver; |
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|
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/* true if the device is non rotational and performs queueing */ |
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bool nonrot_with_queueing; |
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|
|
/* |
|
* Maximum number of requests in driver in the last |
|
* @hw_tag_samples completed requests. |
|
*/ |
|
int max_rq_in_driver; |
|
/* number of samples used to calculate hw_tag */ |
|
int hw_tag_samples; |
|
/* flag set to one if the driver is showing a queueing behavior */ |
|
int hw_tag; |
|
|
|
/* number of budgets assigned */ |
|
int budgets_assigned; |
|
|
|
/* |
|
* Timer set when idling (waiting) for the next request from |
|
* the queue in service. |
|
*/ |
|
struct hrtimer idle_slice_timer; |
|
|
|
/* bfq_queue in service */ |
|
struct bfq_queue *in_service_queue; |
|
|
|
/* on-disk position of the last served request */ |
|
sector_t last_position; |
|
|
|
/* position of the last served request for the in-service queue */ |
|
sector_t in_serv_last_pos; |
|
|
|
/* time of last request completion (ns) */ |
|
u64 last_completion; |
|
|
|
/* bfqq owning the last completed rq */ |
|
struct bfq_queue *last_completed_rq_bfqq; |
|
|
|
/* last bfqq created, among those in the root group */ |
|
struct bfq_queue *last_bfqq_created; |
|
|
|
/* time of last transition from empty to non-empty (ns) */ |
|
u64 last_empty_occupied_ns; |
|
|
|
/* |
|
* Flag set to activate the sampling of the total service time |
|
* of a just-arrived first I/O request (see |
|
* bfq_update_inject_limit()). This will cause the setting of |
|
* waited_rq when the request is finally dispatched. |
|
*/ |
|
bool wait_dispatch; |
|
/* |
|
* If set, then bfq_update_inject_limit() is invoked when |
|
* waited_rq is eventually completed. |
|
*/ |
|
struct request *waited_rq; |
|
/* |
|
* True if some request has been injected during the last service hole. |
|
*/ |
|
bool rqs_injected; |
|
|
|
/* time of first rq dispatch in current observation interval (ns) */ |
|
u64 first_dispatch; |
|
/* time of last rq dispatch in current observation interval (ns) */ |
|
u64 last_dispatch; |
|
|
|
/* beginning of the last budget */ |
|
ktime_t last_budget_start; |
|
/* beginning of the last idle slice */ |
|
ktime_t last_idling_start; |
|
unsigned long last_idling_start_jiffies; |
|
|
|
/* number of samples in current observation interval */ |
|
int peak_rate_samples; |
|
/* num of samples of seq dispatches in current observation interval */ |
|
u32 sequential_samples; |
|
/* total num of sectors transferred in current observation interval */ |
|
u64 tot_sectors_dispatched; |
|
/* max rq size seen during current observation interval (sectors) */ |
|
u32 last_rq_max_size; |
|
/* time elapsed from first dispatch in current observ. interval (us) */ |
|
u64 delta_from_first; |
|
/* |
|
* Current estimate of the device peak rate, measured in |
|
* [(sectors/usec) / 2^BFQ_RATE_SHIFT]. The left-shift by |
|
* BFQ_RATE_SHIFT is performed to increase precision in |
|
* fixed-point calculations. |
|
*/ |
|
u32 peak_rate; |
|
|
|
/* maximum budget allotted to a bfq_queue before rescheduling */ |
|
int bfq_max_budget; |
|
|
|
/* list of all the bfq_queues active on the device */ |
|
struct list_head active_list; |
|
/* list of all the bfq_queues idle on the device */ |
|
struct list_head idle_list; |
|
|
|
/* |
|
* Timeout for async/sync requests; when it fires, requests |
|
* are served in fifo order. |
|
*/ |
|
u64 bfq_fifo_expire[2]; |
|
/* weight of backward seeks wrt forward ones */ |
|
unsigned int bfq_back_penalty; |
|
/* maximum allowed backward seek */ |
|
unsigned int bfq_back_max; |
|
/* maximum idling time */ |
|
u32 bfq_slice_idle; |
|
|
|
/* user-configured max budget value (0 for auto-tuning) */ |
|
int bfq_user_max_budget; |
|
/* |
|
* Timeout for bfq_queues to consume their budget; used to |
|
* prevent seeky queues from imposing long latencies to |
|
* sequential or quasi-sequential ones (this also implies that |
|
* seeky queues cannot receive guarantees in the service |
|
* domain; after a timeout they are charged for the time they |
|
* have been in service, to preserve fairness among them, but |
|
* without service-domain guarantees). |
|
*/ |
|
unsigned int bfq_timeout; |
|
|
|
/* |
|
* Force device idling whenever needed to provide accurate |
|
* service guarantees, without caring about throughput |
|
* issues. CAVEAT: this may even increase latencies, in case |
|
* of useless idling for processes that did stop doing I/O. |
|
*/ |
|
bool strict_guarantees; |
|
|
|
/* |
|
* 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 on the function |
|
* bfq_handle_burst. |
|
*/ |
|
unsigned long last_ins_in_burst; |
|
/* |
|
* Reference time interval used to decide whether a queue has |
|
* been activated shortly after @last_ins_in_burst. |
|
*/ |
|
unsigned long bfq_burst_interval; |
|
/* number of queues in the current burst of queue activations */ |
|
int burst_size; |
|
|
|
/* common parent entity for the queues in the burst */ |
|
struct bfq_entity *burst_parent_entity; |
|
/* Maximum burst size above which the current queue-activation |
|
* burst is deemed as 'large'. |
|
*/ |
|
unsigned long bfq_large_burst_thresh; |
|
/* true if a large queue-activation burst is in progress */ |
|
bool large_burst; |
|
/* |
|
* Head of the burst list (as for the above fields, more |
|
* details in the comments on the function bfq_handle_burst). |
|
*/ |
|
struct hlist_head burst_list; |
|
|
|
/* if set to true, low-latency heuristics are enabled */ |
|
bool low_latency; |
|
/* |
|
* Maximum factor by which the weight of a weight-raised queue |
|
* is multiplied. |
|
*/ |
|
unsigned int bfq_wr_coeff; |
|
/* maximum duration of a weight-raising period (jiffies) */ |
|
unsigned int bfq_wr_max_time; |
|
|
|
/* Maximum weight-raising duration for soft real-time processes */ |
|
unsigned int bfq_wr_rt_max_time; |
|
/* |
|
* Minimum idle period after which weight-raising may be |
|
* reactivated for a queue (in jiffies). |
|
*/ |
|
unsigned int bfq_wr_min_idle_time; |
|
/* |
|
* Minimum period between request arrivals after which |
|
* weight-raising may be reactivated for an already busy async |
|
* queue (in jiffies). |
|
*/ |
|
unsigned long bfq_wr_min_inter_arr_async; |
|
|
|
/* Max service-rate for a soft real-time queue, in sectors/sec */ |
|
unsigned int bfq_wr_max_softrt_rate; |
|
/* |
|
* Cached value of the product ref_rate*ref_wr_duration, used |
|
* for computing the maximum duration of weight raising |
|
* automatically. |
|
*/ |
|
u64 rate_dur_prod; |
|
|
|
/* fallback dummy bfqq for extreme OOM conditions */ |
|
struct bfq_queue oom_bfqq; |
|
|
|
spinlock_t lock; |
|
|
|
/* |
|
* bic associated with the task issuing current bio for |
|
* merging. This and the next field are used as a support to |
|
* be able to perform the bic lookup, needed by bio-merge |
|
* functions, before the scheduler lock is taken, and thus |
|
* avoid taking the request-queue lock while the scheduler |
|
* lock is being held. |
|
*/ |
|
struct bfq_io_cq *bio_bic; |
|
/* bfqq associated with the task issuing current bio for merging */ |
|
struct bfq_queue *bio_bfqq; |
|
|
|
/* |
|
* Depth limits used in bfq_limit_depth (see comments on the |
|
* function) |
|
*/ |
|
unsigned int word_depths[2][2]; |
|
}; |
|
|
|
enum bfqq_state_flags { |
|
BFQQF_just_created = 0, /* queue just allocated */ |
|
BFQQF_busy, /* has requests or is in service */ |
|
BFQQF_wait_request, /* waiting for a request */ |
|
BFQQF_non_blocking_wait_rq, /* |
|
* waiting for a request |
|
* without idling the device |
|
*/ |
|
BFQQF_fifo_expire, /* FIFO checked in this slice */ |
|
BFQQF_has_short_ttime, /* queue has a short think time */ |
|
BFQQF_sync, /* synchronous queue */ |
|
BFQQF_IO_bound, /* |
|
* bfqq has timed-out at least once |
|
* having consumed at most 2/10 of |
|
* its budget |
|
*/ |
|
BFQQF_in_large_burst, /* |
|
* bfqq activated in a large burst, |
|
* see comments to bfq_handle_burst. |
|
*/ |
|
BFQQF_softrt_update, /* |
|
* may need softrt-next-start |
|
* update |
|
*/ |
|
BFQQF_coop, /* bfqq is shared */ |
|
BFQQF_split_coop, /* shared bfqq will be split */ |
|
}; |
|
|
|
#define BFQ_BFQQ_FNS(name) \ |
|
void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \ |
|
void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \ |
|
int bfq_bfqq_##name(const struct bfq_queue *bfqq); |
|
|
|
BFQ_BFQQ_FNS(just_created); |
|
BFQ_BFQQ_FNS(busy); |
|
BFQ_BFQQ_FNS(wait_request); |
|
BFQ_BFQQ_FNS(non_blocking_wait_rq); |
|
BFQ_BFQQ_FNS(fifo_expire); |
|
BFQ_BFQQ_FNS(has_short_ttime); |
|
BFQ_BFQQ_FNS(sync); |
|
BFQ_BFQQ_FNS(IO_bound); |
|
BFQ_BFQQ_FNS(in_large_burst); |
|
BFQ_BFQQ_FNS(coop); |
|
BFQ_BFQQ_FNS(split_coop); |
|
BFQ_BFQQ_FNS(softrt_update); |
|
#undef BFQ_BFQQ_FNS |
|
|
|
/* Expiration reasons. */ |
|
enum bfqq_expiration { |
|
BFQQE_TOO_IDLE = 0, /* |
|
* queue has been idling for |
|
* too long |
|
*/ |
|
BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */ |
|
BFQQE_BUDGET_EXHAUSTED, /* budget consumed */ |
|
BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */ |
|
BFQQE_PREEMPTED /* preemption in progress */ |
|
}; |
|
|
|
struct bfq_stat { |
|
struct percpu_counter cpu_cnt; |
|
atomic64_t aux_cnt; |
|
}; |
|
|
|
struct bfqg_stats { |
|
/* basic stats */ |
|
struct blkg_rwstat bytes; |
|
struct blkg_rwstat ios; |
|
#ifdef CONFIG_BFQ_CGROUP_DEBUG |
|
/* 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 bfq_stat time; |
|
/* sum of number of ios queued across all samples */ |
|
struct bfq_stat avg_queue_size_sum; |
|
/* count of samples taken for average */ |
|
struct bfq_stat avg_queue_size_samples; |
|
/* how many times this group has been removed from service tree */ |
|
struct bfq_stat dequeue; |
|
/* total time spent waiting for it to be assigned a timeslice. */ |
|
struct bfq_stat group_wait_time; |
|
/* time spent idling for this blkcg_gq */ |
|
struct bfq_stat idle_time; |
|
/* total time with empty current active q with other requests queued */ |
|
struct bfq_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_BFQ_CGROUP_DEBUG */ |
|
}; |
|
|
|
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
|
|
|
/* |
|
* struct bfq_group_data - per-blkcg storage for the blkio subsystem. |
|
* |
|
* @ps: @blkcg_policy_storage that this structure inherits |
|
* @weight: weight of the bfq_group |
|
*/ |
|
struct bfq_group_data { |
|
/* must be the first member */ |
|
struct blkcg_policy_data pd; |
|
|
|
unsigned int weight; |
|
}; |
|
|
|
/** |
|
* 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). |
|
* @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. |
|
* @stats: stats for this bfqg. |
|
* @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_may_idle()). |
|
* @rq_pos_tree: rbtree sorted by next_request position, used when |
|
* determining if two or more queues have interleaving |
|
* requests (see bfq_find_close_cooperator()). |
|
* |
|
* 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 @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 { |
|
/* must be the first member */ |
|
struct blkg_policy_data pd; |
|
|
|
/* cached path for this blkg (see comments in bfq_bic_update_cgroup) */ |
|
char blkg_path[128]; |
|
|
|
/* reference counter (see comments in bfq_bic_update_cgroup) */ |
|
int ref; |
|
|
|
struct bfq_entity entity; |
|
struct bfq_sched_data sched_data; |
|
|
|
void *bfqd; |
|
|
|
struct bfq_queue *async_bfqq[2][IOPRIO_NR_LEVELS]; |
|
struct bfq_queue *async_idle_bfqq; |
|
|
|
struct bfq_entity *my_entity; |
|
|
|
int active_entities; |
|
|
|
struct rb_root rq_pos_tree; |
|
|
|
struct bfqg_stats stats; |
|
}; |
|
|
|
#else |
|
struct bfq_group { |
|
struct bfq_entity entity; |
|
struct bfq_sched_data sched_data; |
|
|
|
struct bfq_queue *async_bfqq[2][IOPRIO_NR_LEVELS]; |
|
struct bfq_queue *async_idle_bfqq; |
|
|
|
struct rb_root rq_pos_tree; |
|
}; |
|
#endif |
|
|
|
/* --------------- main algorithm interface ----------------- */ |
|
|
|
#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ |
|
{ RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) |
|
|
|
extern const int bfq_timeout; |
|
|
|
struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync); |
|
void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync); |
|
struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic); |
|
void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
|
void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
|
struct rb_root_cached *root); |
|
void __bfq_weights_tree_remove(struct bfq_data *bfqd, |
|
struct bfq_queue *bfqq, |
|
struct rb_root_cached *root); |
|
void bfq_weights_tree_remove(struct bfq_data *bfqd, |
|
struct bfq_queue *bfqq); |
|
void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
|
bool compensate, enum bfqq_expiration reason); |
|
void bfq_put_queue(struct bfq_queue *bfqq); |
|
void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); |
|
void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
|
void bfq_schedule_dispatch(struct bfq_data *bfqd); |
|
void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); |
|
|
|
/* ------------ end of main algorithm interface -------------- */ |
|
|
|
/* ---------------- cgroups-support interface ---------------- */ |
|
|
|
void bfqg_stats_update_legacy_io(struct request_queue *q, struct request *rq); |
|
void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, |
|
unsigned int op); |
|
void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); |
|
void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); |
|
void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, |
|
u64 io_start_time_ns, unsigned int op); |
|
void bfqg_stats_update_dequeue(struct bfq_group *bfqg); |
|
void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); |
|
void bfqg_stats_update_idle_time(struct bfq_group *bfqg); |
|
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg); |
|
void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg); |
|
void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
|
struct bfq_group *bfqg); |
|
|
|
void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg); |
|
void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio); |
|
void bfq_end_wr_async(struct bfq_data *bfqd); |
|
struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, |
|
struct blkcg *blkcg); |
|
struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); |
|
struct bfq_group *bfqq_group(struct bfq_queue *bfqq); |
|
struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node); |
|
void bfqg_and_blkg_put(struct bfq_group *bfqg); |
|
|
|
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
|
extern struct cftype bfq_blkcg_legacy_files[]; |
|
extern struct cftype bfq_blkg_files[]; |
|
extern struct blkcg_policy blkcg_policy_bfq; |
|
#endif |
|
|
|
/* ------------- end of cgroups-support interface ------------- */ |
|
|
|
/* - interface of the internal hierarchical B-WF2Q+ scheduler - */ |
|
|
|
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
|
/* both next loops stop at one of the child entities of the root group */ |
|
#define for_each_entity(entity) \ |
|
for (; entity ; entity = entity->parent) |
|
|
|
/* |
|
* For each iteration, compute parent in advance, so as to be safe if |
|
* entity is deallocated during the iteration. Such a deallocation may |
|
* happen as a consequence of a bfq_put_queue that frees the bfq_queue |
|
* containing entity. |
|
*/ |
|
#define for_each_entity_safe(entity, parent) \ |
|
for (; entity && ({ parent = entity->parent; 1; }); entity = parent) |
|
|
|
#else /* CONFIG_BFQ_GROUP_IOSCHED */ |
|
/* |
|
* Next two macros are fake loops when cgroups support is not |
|
* enabled. I fact, in such a case, there is only one level to go up |
|
* (to reach the root group). |
|
*/ |
|
#define for_each_entity(entity) \ |
|
for (; entity ; entity = NULL) |
|
|
|
#define for_each_entity_safe(entity, parent) \ |
|
for (parent = NULL; entity ; entity = parent) |
|
#endif /* CONFIG_BFQ_GROUP_IOSCHED */ |
|
|
|
struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq); |
|
struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); |
|
unsigned int bfq_tot_busy_queues(struct bfq_data *bfqd); |
|
struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity); |
|
struct bfq_entity *bfq_entity_of(struct rb_node *node); |
|
unsigned short bfq_ioprio_to_weight(int ioprio); |
|
void bfq_put_idle_entity(struct bfq_service_tree *st, |
|
struct bfq_entity *entity); |
|
struct bfq_service_tree * |
|
__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, |
|
struct bfq_entity *entity, |
|
bool update_class_too); |
|
void bfq_bfqq_served(struct bfq_queue *bfqq, int served); |
|
void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
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unsigned long time_ms); |
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bool __bfq_deactivate_entity(struct bfq_entity *entity, |
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bool ins_into_idle_tree); |
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bool next_queue_may_preempt(struct bfq_data *bfqd); |
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struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); |
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bool __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); |
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void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
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bool ins_into_idle_tree, bool expiration); |
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void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
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void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
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bool expiration); |
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void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
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bool expiration); |
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void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
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/* --------------- end of interface of B-WF2Q+ ---------------- */ |
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/* Logging facilities. */ |
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static inline void bfq_pid_to_str(int pid, char *str, int len) |
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{ |
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if (pid != -1) |
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snprintf(str, len, "%d", pid); |
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else |
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snprintf(str, len, "SHARED-"); |
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} |
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#ifdef CONFIG_BFQ_GROUP_IOSCHED |
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struct bfq_group *bfqq_group(struct bfq_queue *bfqq); |
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#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ |
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char pid_str[MAX_PID_STR_LENGTH]; \ |
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if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) \ |
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break; \ |
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bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); \ |
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blk_add_cgroup_trace_msg((bfqd)->queue, \ |
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bfqg_to_blkg(bfqq_group(bfqq))->blkcg, \ |
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"bfq%s%c " fmt, pid_str, \ |
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bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args); \ |
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} while (0) |
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#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ |
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blk_add_cgroup_trace_msg((bfqd)->queue, \ |
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bfqg_to_blkg(bfqg)->blkcg, fmt, ##args); \ |
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} while (0) |
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#else /* CONFIG_BFQ_GROUP_IOSCHED */ |
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#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ |
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char pid_str[MAX_PID_STR_LENGTH]; \ |
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if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) \ |
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break; \ |
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bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); \ |
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blk_add_trace_msg((bfqd)->queue, "bfq%s%c " fmt, pid_str, \ |
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bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ |
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##args); \ |
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} while (0) |
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#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) |
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#endif /* CONFIG_BFQ_GROUP_IOSCHED */ |
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#define bfq_log(bfqd, fmt, args...) \ |
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blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) |
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#endif /* _BFQ_H */
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