Commit eed3ecc9 authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

block, bfq: do not idle if only one group is activated 



Now that root group is counted into 'num_groups_with_pending_reqs',
'num_groups_with_pending_reqs > 0' is always true in
bfq_asymmetric_scenario(). Thus change the condition to '> 1'.

On the other hand, this change can enable concurrent sync io if only
one group is activated.

Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-5-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 71f8ca77

block/bfq-iosched.c

+2 −2
Original line number Diff line number Diff line
@@ -820,7 +820,7 @@ bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) 
 * much easier to maintain the needed state:

 * 1) all active queues have the same weight,

 * 2) all active queues belong to the same I/O-priority class,

 * 3) there are no active groups.

 * 3) there is at most one active group.

 * In particular, the last condition is always true if hierarchical

 * support or the cgroups interface are not enabled, thus no state

 * needs to be maintained in this case.
@@ -852,7 +852,7 @@ static bool bfq_asymmetric_scenario(struct bfq_data *bfqd, 


	return varied_queue_weights || multiple_classes_busy

#ifdef CONFIG_BFQ_GROUP_IOSCHED

	       || bfqd->num_groups_with_pending_reqs > 0

	       || bfqd->num_groups_with_pending_reqs > 1

#endif

		;

}