Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [patch, v2] blk-mq: avoid excessive boot delays with large lun counts | Date | Mon, 02 Nov 2015 09:04:37 -0500 |
| |
Ming Lei <tom.leiming@gmail.com> writes:
> You can add > Reviewed-by: Ming Lei <ming.lei@canonical.com> > if the following trivial issues(especially the 2nd one) are addressed.
[snip]
>> @@ -1891,7 +1890,12 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q) >> >> mutex_lock(&set->tag_list_lock); >> list_del_init(&q->tag_set_list); >> - blk_mq_update_tag_set_depth(set); >> + if (set->tag_list.next == set->tag_list.prev) { > > list_is_singular() should be better.
Didn't even know that existed. Thanks.
>> + /* just transitioned to unshared */ >> + set->flags &= ~BLK_MQ_F_TAG_SHARED; >> + /* update existing queue */ >> + blk_mq_update_tag_set_depth(set, false); >> + } >> mutex_unlock(&set->tag_list_lock); >> } >> >> @@ -1901,8 +1905,17 @@ static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, >> q->tag_set = set; >> >> mutex_lock(&set->tag_list_lock); >> + >> + /* Check to see if we're transitioning to shared (from 1 to 2 queues). */ >> + if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) { >> + set->flags |= BLK_MQ_F_TAG_SHARED; >> + /* update existing queue */ >> + blk_mq_update_tag_set_depth(set, true); >> + } >> + if (set->flags & BLK_MQ_F_TAG_SHARED) > > The above should be 'else if', otherwise the current queue will be set > twice.
I moved the list add below this to avoid that very issue. See:
>> + queue_set_hctx_shared(q, true); >> list_add_tail(&q->tag_set_list, &set->tag_list); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This seemed the cleanest way to structure the code to avoid the double walking of the hctx list for the current q.
-Jeff
>> - blk_mq_update_tag_set_depth(set); >> + >> mutex_unlock(&set->tag_list_lock); >> } >>
| |