block, bfq: record how many queues have pending requests

Prepare to refactor the counting of 'num_groups_with_pending_reqs'.

Add a counter in bfq_group, update it while tracking if bfqq have pending
requests and when bfq_bfqq_move() is called.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 144bca0..4c37398 100644 (file)
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -552,6 +552,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd)
                                   */
        bfqg->bfqd = bfqd;
        bfqg->active_entities = 0;
+       bfqg->num_queues_with_pending_reqs = 0;
        bfqg->online = true;
        bfqg->rq_pos_tree = RB_ROOT;
 }
@@ -641,6 +642,7 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 {
        struct bfq_entity *entity = &bfqq->entity;
        struct bfq_group *old_parent = bfqq_group(bfqq);
+       bool has_pending_reqs = false;
 
        /*
         * No point to move bfqq to the same group, which can happen when
@@ -661,6 +663,11 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
         */
        bfqq->ref++;
 
+       if (entity->in_groups_with_pending_reqs) {
+               has_pending_reqs = true;
+               bfq_del_bfqq_in_groups_with_pending_reqs(bfqq);
+       }
+
        /* If bfqq is empty, then bfq_bfqq_expire also invokes
         * bfq_del_bfqq_busy, thereby removing bfqq and its entity
         * from data structures related to current group. Otherwise we
@@ -688,6 +695,9 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
        /* pin down bfqg and its associated blkg  */
        bfqg_and_blkg_get(bfqg);
 
+       if (has_pending_reqs)
+               bfq_add_bfqq_in_groups_with_pending_reqs(bfqq);
+
        if (bfq_bfqq_busy(bfqq)) {
                if (unlikely(!bfqd->nonrot_with_queueing))
                        bfq_pos_tree_add_move(bfqd, bfqq);

diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 42c910f..35b366e 100644 (file)
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -939,6 +939,7 @@ struct bfq_group {
        struct bfq_entity *my_entity;
 
        int active_entities;
+       int num_queues_with_pending_reqs;
 
        struct rb_root rq_pos_tree;
 

diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index bd8f4ed..5549ccf 100644 (file)
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -1650,16 +1650,24 @@ void bfq_add_bfqq_in_groups_with_pending_reqs(struct bfq_queue *bfqq)
 {
        struct bfq_entity *entity = &bfqq->entity;
 
-       if (!entity->in_groups_with_pending_reqs)
+       if (!entity->in_groups_with_pending_reqs) {
                entity->in_groups_with_pending_reqs = true;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+               bfqq_group(bfqq)->num_queues_with_pending_reqs++;
+#endif
+       }
 }
 
 void bfq_del_bfqq_in_groups_with_pending_reqs(struct bfq_queue *bfqq)
 {
        struct bfq_entity *entity = &bfqq->entity;
 
-       if (entity->in_groups_with_pending_reqs)
+       if (entity->in_groups_with_pending_reqs) {
                entity->in_groups_with_pending_reqs = false;
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+               bfqq_group(bfqq)->num_queues_with_pending_reqs--;
+#endif
+       }
 }
 
 /*