blk-throttle: add configure option for new .low interface

As discussed in LSF, add configure option for the interface and mark it
as experimental, so people can try/test.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/Kconfig b/block/Kconfig
index e9f780f..89cd28f 100644 (file)
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -115,6 +115,18 @@ config BLK_DEV_THROTTLING
 
        See Documentation/cgroups/blkio-controller.txt for more information.
 
+config BLK_DEV_THROTTLING_LOW
+       bool "Block throttling .low limit interface support (EXPERIMENTAL)"
+       depends on BLK_DEV_THROTTLING
+       default n
+       ---help---
+       Add .low limit interface for block throttling. The low limit is a best
+       effort limit to prioritize cgroups. Depending on the setting, the limit
+       can be used to protect cgroups in terms of bandwidth/iops and better
+       utilize disk resource.
+
+       Note, this is an experimental interface and could be changed someday.
+
 config BLK_CMDLINE_PARSER
        bool "Block device command line partition parser"
        default n