[PATCH RFC RESEND 03/14] block: add hierarchical-support option to kconfig

[paolo]

From: Fabio Checconi <fchecconi at gmail.com>

Add the CGROUP_BFQIO option to Kconfig.iosched. This option allows
full hierarchical support to be enabled in BFQ, and the bfqio
controller to be added to the cgroups interface.

Signed-off-by: Fabio Checconi <fchecconi at gmail.com>
Signed-off-by: Paolo Valente <paolo.valente at unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna at gmail.com>
---
 block/Kconfig.iosched | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 8f98cc7..a3675cb 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -46,7 +46,18 @@ config IOSCHED_BFQ
 	  The BFQ I/O scheduler tries to distribute bandwidth among all
 	  processes according to their weights.
 	  It aims at distributing the bandwidth as desired, regardless
-	  of the disk parameters and with any workload.
+	  of the disk parameters and with any workload. If compiled
+	  built-in (saying Y here), BFQ can be configured to support
+	  hierarchical scheduling.
+
+config CGROUP_BFQIO
+	bool "BFQ hierarchical scheduling support"
+	depends on CGROUPS && IOSCHED_BFQ=y
+	default n
+	---help---
+	  Enable hierarchical scheduling in BFQ, using the cgroups
+	  filesystem interface.  The name of the subsystem will be
+	  bfqio.
 
 choice
 	prompt "Default I/O scheduler"
-- 
1.9.2