On 11/19/21 4:18 AM, Ming Lei wrote:
Chao Leng reported that in case of lots of namespaces, it may take quite a
while for nvme_stop_queues() to quiesce all namespace queues.
Improve nvme_stop_queues() by running quiesce in parallel, and just wait
once if global quiesce wait is allowed.
Link: https://lore.kernel.org/linux-block/cc732195-c053-9ce4-e1a7-e7f6dcf762ac@xxxxxxxxxx/
Reported-by: Chao Leng <lengchao@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/nvme/host/core.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 4b5de8f5435a..06741d3ed72b 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4517,9 +4517,7 @@ static void nvme_start_ns_queue(struct nvme_ns *ns)
static void nvme_stop_ns_queue(struct nvme_ns *ns)
{
if (!test_and_set_bit(NVME_NS_STOPPED, &ns->flags))
- blk_mq_quiesce_queue(ns->queue);
- else
- blk_mq_wait_quiesce_done(ns->queue);
+ blk_mq_quiesce_queue_nowait(ns->queue);
}
/*
@@ -4620,6 +4618,11 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl)
down_read(&ctrl->namespaces_rwsem);
list_for_each_entry(ns, &ctrl->namespaces, list)
nvme_stop_ns_queue(ns);
+ list_for_each_entry(ns, &ctrl->namespaces, list) {
+ blk_mq_wait_quiesce_done(ns->queue);
+ if (blk_mq_global_quiesce_wait(ns->queue))
+ break;
+ }
up_read(&ctrl->namespaces_rwsem);
Can you quantify how much of a difference it is to do rcu_read_unlock()
for every queue? The big improvement here is that it is done in parallel
instead of serially. Just wandering if it is worth the less than elegant
interface...
