// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Hierarchical Budget Worst-case Fair Weighted Fair Queueing
* (B-WF2Q+): hierarchical scheduling algorithm by which the BFQ I/O
* scheduler schedules generic entities. The latter can represent
* either single bfq queues (associated with processes) or groups of
* bfq queues (associated with cgroups).
*/
#include "bfq-iosched.h"
/**
* bfq_gt - compare two timestamps.
* @a: first ts.
* @b: second ts.
*
* Return @a > @b, dealing with wrapping correctly.
*/
static int bfq_gt(u64 a, u64 b)
{
return (s64)(a - b) > 0;
}
static struct bfq_entity *bfq_root_active_entity(struct rb_root *tree)
{
struct rb_node *node = tree->rb_node;
return rb_entry(node, struct bfq_entity, rb_node);
}
static unsigned int bfq_class_idx(struct bfq_entity *entity)
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
return bfqq ? bfqq->ioprio_class - 1 :
BFQ_DEFAULT_GRP_CLASS - 1;
}
unsigned int bfq_tot_busy_queues(struct bfq_data *bfqd)
{
return bfqd->busy_queues[0] + bfqd->busy_queues[1] +
bfqd->busy_queues[2];
}
static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd,
bool expiration);
static bool bfq_update_parent_budget(struct bfq_entity *next_in_service);
/**
* bfq_update_next_in_service - update sd->next_in_service
* @sd: sched_data for which to perform the update.
* @new_entity: if not NULL, pointer to the entity whose activation,
* r
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