[PATCH -next 08/11] block, bfq: record how many queues have pending requests in bfq_group

From: Yu Kuai
Date: Sat Mar 05 2022 - 03:57:10 EST


Prepare to decrease 'num_groups_with_pending_reqs' earlier.

bfqq will be inserted to weights_tree when new io is inserted to it, and
bfqq will be removed from weights_tree when all the requests are completed.
Thus use weights_tree insertion and removal to track how many queues have
pending requests.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/bfq-cgroup.c | 1 +
block/bfq-iosched.c | 15 +++++++++++++++
block/bfq-iosched.h | 1 +
3 files changed, 17 insertions(+)

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 6cd65b5e790d..58acaf14a91d 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -557,6 +557,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd)
*/
bfqg->bfqd = bfqd;
bfqg->active_entities = 0;
+ bfqg->num_entities_with_pending_reqs = 0;
bfqg->rq_pos_tree = RB_ROOT;
}

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 07027dc9dc4c..2a48c40b4f02 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -928,6 +928,13 @@ void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq,
inc_counter:
bfqq->weight_counter->num_active++;
bfqq->ref++;
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ if (!entity->in_groups_with_pending_reqs) {
+ entity->in_groups_with_pending_reqs = true;
+ bfqq_group(bfqq)->num_entities_with_pending_reqs++;
+ }
+#endif
}

/*
@@ -944,6 +951,14 @@ void __bfq_weights_tree_remove(struct bfq_data *bfqd,
return;

bfqq->weight_counter->num_active--;
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+ if (bfqq->entity.in_groups_with_pending_reqs) {
+ bfqq->entity.in_groups_with_pending_reqs = false;
+ bfqq_group(bfqq)->num_entities_with_pending_reqs--;
+ }
+#endif
+
if (bfqq->weight_counter->num_active > 0)
goto reset_entity_pointer;

diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 4530ab8b42ac..5d904851519c 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -940,6 +940,7 @@ struct bfq_group {
struct bfq_entity *my_entity;

int active_entities;
+ int num_entities_with_pending_reqs;

struct rb_root rq_pos_tree;

--
2.31.1