drbd: Create a dedicated workqueue for sending acks on the control connection
authorPhilipp Reisner <philipp.reisner@linbit.com>
Mon, 16 Mar 2015 15:08:29 +0000 (16:08 +0100)
committerJens Axboe <axboe@fb.com>
Wed, 25 Nov 2015 16:22:01 +0000 (09:22 -0700)
commit668700b40a7c8727bbd2b3fd4fd22e0ce3f1aeb6
tree20c6ee044e5d91700bea7c3d3a601ecf3234753d
parent1c03e52083c8fa6e70a0b921d25d1916f68320fc
drbd: Create a dedicated workqueue for sending acks on the control connection

The intention is to reduce CPU utilization. Recent measurements
unveiled that the current performance bottleneck is CPU utilization
on the receiving node. The asender thread became CPU limited.

One of the main points is to eliminate the idr_for_each_entry() loop
from the sending acks code path.

One exception in that is sending back ping_acks. These stay
in the ack-receiver thread. Otherwise the logic becomes too
complicated for no added value.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
drivers/block/drbd/drbd_int.h
drivers/block/drbd/drbd_main.c
drivers/block/drbd/drbd_nl.c
drivers/block/drbd/drbd_protocol.h
drivers/block/drbd/drbd_receiver.c
drivers/block/drbd/drbd_req.c
drivers/block/drbd/drbd_worker.c