rdmacg: Added documentation for rdmacg

Added documentation for v1 and v2 version describing high
level design and usage examples on using rdma controller.

Signed-off-by: Parav Pandit <pandit.parav@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 4cc07ce3b8dd..94350d79e169 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -47,6 +47,8 @@ CONTENTS
   5-3. IO
     5-3-1. IO Interface Files
     5-3-2. Writeback
+  5-4. RDMA
+    5-4-1. RDMA Interface Files
 6. Namespace
   6-1. Basics
   6-2. The Root and Views
@@ -1119,6 +1121,42 @@ writeback as follows.
 	vm.dirty[_background]_ratio.
 
 
+5-4. RDMA
+
+The "rdma" controller regulates the distribution and accounting of
+of RDMA resources.
+
+5-4-1. RDMA Interface Files
+
+  rdma.max
+	A readwrite nested-keyed file that exists for all the cgroups
+	except root that describes current configured resource limit
+	for a RDMA/IB device.
+
+	Lines are keyed by device name and are not ordered.
+	Each line contains space separated resource name and its configured
+	limit that can be distributed.
+
+	The following nested keys are defined.
+
+	  hca_handle	Maximum number of HCA Handles
+	  hca_object 	Maximum number of HCA Objects
+
+	An example for mlx4 and ocrdma device follows.
+
+	  mlx4_0 hca_handle=2 hca_object=2000
+	  ocrdma1 hca_handle=3 hca_object=max
+
+  rdma.current
+	A read-only file that describes current resource usage.
+	It exists for all the cgroup except root.
+
+	An example for mlx4 and ocrdma device follows.
+
+	  mlx4_0 hca_handle=1 hca_object=20
+	  ocrdma1 hca_handle=1 hca_object=23
+
+
 6. Namespace
 
 6-1. Basics