| Message ID | 20211117115502.1600950-1-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: avoid to quiesce queue in elevator_init_mq | expand |
On Wed, 17 Nov 2021 19:55:02 +0800, Ming Lei wrote: > elevator_init_mq() is only called before adding disk, when there isn't > any FS I/O, only passthrough requests can be queued, so freezing queue > plus canceling dispatch work is enough to drain any dispatch activities, > then we can avoid synchronize_srcu() in blk_mq_quiesce_queue(). > > Long boot latency issue can be fixed in case of lots of disks added > during booting. > > [...] Applied, thanks! [1/1] block: avoid to quiesce queue in elevator_init_mq commit: 245a489e81e13dd55ae46d27becf6d5901eb7828 Best regards,
diff --git a/block/elevator.c b/block/elevator.c index 1f39f6e8ebb9..19a78d5516ba 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -694,12 +694,18 @@ void elevator_init_mq(struct request_queue *q) if (!e) return; + /* + * We are called before adding disk, when there isn't any FS I/O, + * so freezing queue plus canceling dispatch work is enough to + * drain any dispatch activities originated from passthrough + * requests, then no need to quiesce queue which may add long boot + * latency, especially when lots of disks are involved. + */ blk_mq_freeze_queue(q); - blk_mq_quiesce_queue(q); + blk_mq_cancel_work_sync(q); err = blk_mq_init_sched(q, e); - blk_mq_unquiesce_queue(q); blk_mq_unfreeze_queue(q); if (err) {
elevator_init_mq() is only called before adding disk, when there isn't any FS I/O, only passthrough requests can be queued, so freezing queue plus canceling dispatch work is enough to drain any dispatch activities, then we can avoid synchronize_srcu() in blk_mq_quiesce_queue(). Long boot latency issue can be fixed in case of lots of disks added during booting. Fixes: 737eb78e82d5 ("block: Delay default elevator initialization") Reported-by: yangerkun <yangerkun@huawei.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/elevator.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)