The BFQ I/O scheduler features an optimal fair-queuing (proportional-share) scheduling algorithm, enriched with several mechanisms to boost throughput and reduce latency for interactive and real-time applications. This makes BFQ a large and complex piece of code. This commit addresses this issue by splitting BFQ into three main, independent components, and by moving each component into a separate source file: 1. Main algorithm: handles the interaction with the kernel, and decides which requests to dispatch; it uses the following two further components to achieve its goals. 2. Scheduling engine (Hierarchical B-WF2Q+ scheduling algorithm): computes the schedule, using weights and budgets provided by the above component. 3. cgroups support: handles group operations (creation, destruction, move, ...). Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@fb.com>tirimbino
Paolo Valente
8 years ago
committed by
Jens Axboe
parent
6fa3e8d342
commit
ea25da4808
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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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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License as |
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* published by the Free Software Foundation; either version 2 of the |
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* License, or (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* General Public License for more details. |
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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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#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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/*
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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 on a hierarchical setup. @next_in_service |
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* points to the active entity of the sched_data service trees that |
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* will be scheduled next. It is used to reduce the number of steps |
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* needed for each hierarchical-schedule update. |
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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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* All the fields are protected by the queue 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 entities |
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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 entities this counter refers to */ |
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unsigned int num_active; /* nr of active entities with this weight */ |
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/*
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* Weights tree member (see bfq_data's @queue_weights_tree and |
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* @group_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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/* pointer to the weight counter associated with this entity */ |
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struct bfq_weight_counter *weight_counter; |
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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; |
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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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/* 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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}; |
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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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/* 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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/*
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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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/* 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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/* 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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* 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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}; |
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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 idle window before merging; taken to |
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* remember this value while the queue is merged, so as to be |
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* able to restore it in case of split. |
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*/ |
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bool saved_idle_window; |
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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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/*
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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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* 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_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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}; |
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enum bfq_device_speed { |
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BFQ_BFQD_FAST, |
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BFQ_BFQD_SLOW, |
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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 queue_weights_tree; |
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/*
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* rbtree of non-queue @bfq_entity weight counters, sorted by |
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* weight. Used to keep track of whether all @bfq_groups 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 @bfq_group (see |
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* the comments to the functions bfq_weights_tree_[add|remove] |
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* for further details). |
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*/ |
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struct rb_root group_weights_tree; |
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/*
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* Number of bfq_queues containing requests (including the |
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* queue in service, even if it is idling). |
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*/ |
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int busy_queues; |
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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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* Maximum number of requests in driver in the last |
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* @hw_tag_samples completed requests. |
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*/ |
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int max_rq_in_driver; |
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/* number of samples used to calculate hw_tag */ |
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int hw_tag_samples; |
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/* flag set to one if the driver is showing a queueing behavior */ |
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int hw_tag; |
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/* number of budgets assigned */ |
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int budgets_assigned; |
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/*
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* Timer set when idling (waiting) for the next request from |
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* the queue in service. |
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*/ |
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struct hrtimer idle_slice_timer; |
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/* bfq_queue in service */ |
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struct bfq_queue *in_service_queue; |
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/* on-disk position of the last served request */ |
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sector_t last_position; |
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/* time of last request completion (ns) */ |
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u64 last_completion; |
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/* time of first rq dispatch in current observation interval (ns) */ |
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u64 first_dispatch; |
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/* time of last rq dispatch in current observation interval (ns) */ |
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u64 last_dispatch; |
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/* beginning of the last budget */ |
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ktime_t last_budget_start; |
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/* beginning of the last idle slice */ |
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ktime_t last_idling_start; |
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/* number of samples in current observation interval */ |
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int peak_rate_samples; |
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/* num of samples of seq dispatches in current observation interval */ |
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u32 sequential_samples; |
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/* total num of sectors transferred in current observation interval */ |
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u64 tot_sectors_dispatched; |
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/* max rq size seen during current observation interval (sectors) */ |
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u32 last_rq_max_size; |
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/* time elapsed from first dispatch in current observ. interval (us) */ |
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u64 delta_from_first; |
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/*
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* Current estimate of the device peak rate, measured in |
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* [BFQ_RATE_SHIFT * sectors/usec]. The left-shift by |
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* BFQ_RATE_SHIFT is performed to increase precision in |
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* fixed-point calculations. |
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*/ |
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u32 peak_rate; |
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|
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/* maximum budget allotted to a bfq_queue before rescheduling */ |
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int bfq_max_budget; |
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/* list of all the bfq_queues active on the device */ |
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struct list_head active_list; |
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/* list of all the bfq_queues idle on the device */ |
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struct list_head idle_list; |
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/*
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* Timeout for async/sync requests; when it fires, requests |
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* are served in fifo order. |
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*/ |
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u64 bfq_fifo_expire[2]; |
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/* weight of backward seeks wrt forward ones */ |
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unsigned int bfq_back_penalty; |
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/* maximum allowed backward seek */ |
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unsigned int bfq_back_max; |
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/* maximum idling time */ |
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u32 bfq_slice_idle; |
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|
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/* user-configured max budget value (0 for auto-tuning) */ |
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int bfq_user_max_budget; |
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/*
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* Timeout for bfq_queues to consume their budget; used to |
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* prevent seeky queues from imposing long latencies to |
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* sequential or quasi-sequential ones (this also implies that |
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* seeky queues cannot receive guarantees in the service |
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* domain; after a timeout they are charged for the time they |
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* have been in service, to preserve fairness among them, but |
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* without service-domain guarantees). |
||||
*/ |
||||
unsigned int bfq_timeout; |
||||
|
||||
/*
|
||||
* 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). |
||||
*/ |
||||
unsigned int bfq_requests_within_timer; |
||||
|
||||
/*
|
||||
* 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 R*T, used for computing the |
||||
* maximum duration of weight raising automatically. |
||||
*/ |
||||
u64 RT_prod; |
||||
/* device-speed class for the low-latency heuristic */ |
||||
enum bfq_device_speed device_speed; |
||||
|
||||
/* 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; |
||||
}; |
||||
|
||||
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_idle_window, /* slice idling enabled */ |
||||
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(idle_window); |
||||
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 bfqg_stats { |
||||
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
||||
/* number of ios merged */ |
||||
struct blkg_rwstat merged; |
||||
/* total time spent on device in ns, may not be accurate w/ queueing */ |
||||
struct blkg_rwstat service_time; |
||||
/* total time spent waiting in scheduler queue in ns */ |
||||
struct blkg_rwstat wait_time; |
||||
/* number of IOs queued up */ |
||||
struct blkg_rwstat queued; |
||||
/* total disk time and nr sectors dispatched by this group */ |
||||
struct blkg_stat time; |
||||
/* sum of number of ios queued across all samples */ |
||||
struct blkg_stat avg_queue_size_sum; |
||||
/* count of samples taken for average */ |
||||
struct blkg_stat avg_queue_size_samples; |
||||
/* how many times this group has been removed from service tree */ |
||||
struct blkg_stat dequeue; |
||||
/* total time spent waiting for it to be assigned a timeslice. */ |
||||
struct blkg_stat group_wait_time; |
||||
/* time spent idling for this blkcg_gq */ |
||||
struct blkg_stat idle_time; |
||||
/* total time with empty current active q with other requests queued */ |
||||
struct blkg_stat empty_time; |
||||
/* fields after this shouldn't be cleared on stat reset */ |
||||
uint64_t start_group_wait_time; |
||||
uint64_t start_idle_time; |
||||
uint64_t start_empty_time; |
||||
uint16_t flags; |
||||
#endif /* CONFIG_BFQ_GROUP_IOSCHED */ |
||||
}; |
||||
|
||||
#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; |
||||
|
||||
struct bfq_entity entity; |
||||
struct bfq_sched_data sched_data; |
||||
|
||||
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 rb_root rq_pos_tree; |
||||
|
||||
struct bfqg_stats stats; |
||||
}; |
||||
|
||||
#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; |
||||
|
||||
struct rb_root rq_pos_tree; |
||||
}; |
||||
#endif |
||||
|
||||
struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); |
||||
|
||||
/* --------------- 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_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
||||
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_entity *entity, |
||||
struct rb_root *root); |
||||
void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity, |
||||
struct rb_root *root); |
||||
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_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 ---------------- */ |
||||
|
||||
extern struct cftype bfq_blkcg_legacy_files[]; |
||||
extern struct cftype bfq_blkg_files[]; |
||||
|
||||
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, uint64_t start_time, |
||||
uint64_t io_start_time, 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_put(struct bfq_group *bfqg); |
||||
|
||||
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
||||
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); |
||||
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); |
||||
void bfq_bfqq_served(struct bfq_queue *bfqq, int served); |
||||
void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
||||
unsigned long time_ms); |
||||
bool __bfq_deactivate_entity(struct bfq_entity *entity, |
||||
bool ins_into_idle_tree); |
||||
bool next_queue_may_preempt(struct bfq_data *bfqd); |
||||
struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); |
||||
void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); |
||||
void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
||||
bool ins_into_idle_tree, bool expiration); |
||||
void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
||||
void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
||||
void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
||||
bool expiration); |
||||
void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); |
||||
|
||||
/* --------------- end of interface of B-WF2Q+ ---------------- */ |
||||
|
||||
/* Logging facilities. */ |
||||
#ifdef CONFIG_BFQ_GROUP_IOSCHED |
||||
struct bfq_group *bfqq_group(struct bfq_queue *bfqq); |
||||
|
||||
#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ |
||||
char __pbuf[128]; \
|
||||
\
|
||||
blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \
|
||||
blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid, \
|
||||
bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
|
||||
__pbuf, ##args); \
|
||||
} while (0) |
||||
|
||||
#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ |
||||
char __pbuf[128]; \
|
||||
\
|
||||
blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \
|
||||
blk_add_trace_msg((bfqd)->queue, "%s " fmt, __pbuf, ##args); \
|
||||
} while (0) |
||||
|
||||
#else /* CONFIG_BFQ_GROUP_IOSCHED */ |
||||
|
||||
#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ |
||||
blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
|
||||
bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
|
||||
##args) |
||||
#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) |
||||
|
||||
#endif /* CONFIG_BFQ_GROUP_IOSCHED */ |
||||
|
||||
#define bfq_log(bfqd, fmt, args...) \ |
||||
blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) |
||||
|
||||
#endif /* _BFQ_H */ |
||||
File diff suppressed because it is too large
Load Diff
Loading…
Reference in new issue