sched: Introduce primitives to account for CFS bandwidth tracking

In this patch we introduce the notion of CFS bandwidth, partitioned into
globally unassigned bandwidth, and locally claimed bandwidth.

 - The global bandwidth is per task_group, it represents a pool of unclaimed
   bandwidth that cfs_rqs can allocate from.
 - The local bandwidth is tracked per-cfs_rq, this represents allotments from
   the global pool bandwidth assigned to a specific cpu.

Bandwidth is managed via cgroupfs, adding two new interfaces to the cpu subsystem:
 - cpu.cfs_period_us : the bandwidth period in usecs
 - cpu.cfs_quota_us : the cpu bandwidth (in usecs) that this tg will be allowed
   to consume over period above.

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Nikhil Rao <ncrao@google.com>
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184756.972636699@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 12 insertions, 0 deletions

diff --git a/init/Kconfig b/init/Kconfig
index d62778390e55..d19b3a77ab44 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -715,6 +715,18 @@ config FAIR_GROUP_SCHED
         depends on CGROUP_SCHED
         default CGROUP_SCHED
 
+config CFS_BANDWIDTH
+        bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
+        depends on EXPERIMENTAL
+        depends on FAIR_GROUP_SCHED
+        default n
+        help
+          This option allows users to define CPU bandwidth rates (limits) for
+          tasks running within the fair group scheduler.  Groups with no limit
+          set are considered to be unconstrained and will run with no
+          restriction.
+          See tip/Documentation/scheduler/sched-bwc.txt for more information.
+
 config RT_GROUP_SCHED
         bool "Group scheduling for SCHED_RR/FIFO"
         depends on EXPERIMENTAL