dm mpath: add service time load balancer

This patch adds a service time oriented dynamic load balancer,
dm-service-time, which selects the path with the shortest estimated
service time for the incoming I/O.
The service time is estimated by dividing the in-flight I/O size
by a performance value of each path.

The performance value can be given as a table argument at the table
loading time.  If no performance value is given, all paths are
considered equal.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index ff9f545dd516..dade52f60733 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_DM_CRYPT)		+= dm-crypt.o
 obj-$(CONFIG_DM_DELAY)          += dm-delay.o
 obj-$(CONFIG_DM_MULTIPATH)      += dm-multipath.o dm-round-robin.o
 obj-$(CONFIG_DM_MULTIPATH_QL)   += dm-queue-length.o
+obj-$(CONFIG_DM_MULTIPATH_ST)   += dm-service-time.o
 obj-$(CONFIG_DM_SNAPSHOT)       += dm-snapshot.o
 obj-$(CONFIG_DM_MIRROR)         += dm-mirror.o dm-log.o dm-region-hash.o
 obj-$(CONFIG_DM_ZERO)           += dm-zero.o