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>
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index ff9f545..dade52f 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -37,6 +37,7 @@
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