Messages in this thread | | | Date | Tue, 3 Nov 2015 09:12:16 +0800 | Subject | Re: [patch, v2] blk-mq: avoid excessive boot delays with large lun counts | From | Ming Lei <> |
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On Mon, Nov 2, 2015 at 10:04 PM, Jeff Moyer <jmoyer@redhat.com> wrote: > 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.
OK, it is correct, then v1 is fine.
Reviewed-by: Ming Lei <ming.lei@canonical.com>
> > -Jeff > >>> - blk_mq_update_tag_set_depth(set); >>> + >>> mutex_unlock(&set->tag_list_lock); >>> } >>>
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