Docs/admin-guide/cgroup-v1: document rdma.peak, rdma.events and rdma.events.local

The v1 RDMA controller documentation only describes rdma.max and
rdma.current, but the controller exposes three more files -- rdma.peak,
rdma.events and rdma.events.local -- which are already documented for
v2. Mirror the v2 wording so the v1 documentation matches the files
actually visible on a v1 mount.

Co-developed-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/Documentation/admin-guide/cgroup-v1/rdma.rst b/Documentation/admin-guide/cgroup-v1/rdma.rst
index e69369b7252ea390d79c21294565709cd126296e..abddf34d266752575e6b4a6934cdc6c0dcf4d293 100644 (file)
--- a/Documentation/admin-guide/cgroup-v1/rdma.rst
+++ b/Documentation/admin-guide/cgroup-v1/rdma.rst
@@ -9,6 +9,7 @@ RDMA Controller
      1-2. Why RDMA controller needed?
      1-3. How is RDMA controller implemented?
    2. Usage Examples
+   3. RDMA Interface Files
 
 1. Overview
 ===========
@@ -115,3 +116,68 @@ Following resources can be accounted by rdma controller.
 (d) Delete resource limit::
 
        echo mlx4_0 hca_handle=max hca_object=max > /sys/fs/cgroup/rdma/1/rdma.max
+
+3. RDMA Interface Files
+========================
+
+The following interface files are available in each non-root RDMA cgroup.
+
+  rdma.max
+       A read-write file which describes the configured resource limit
+       for an RDMA/IB device.  See the Usage Examples above.
+
+  rdma.current
+       A read-only file which describes the current resource usage.
+
+  rdma.peak
+       A read-only nested-keyed file which shows the historical high
+       watermark of resource usage per device since the cgroup was created.
+
+       An example for mlx4 and ocrdma device follows::
+
+         mlx4_0 hca_handle=1 hca_object=20
+         ocrdma1 hca_handle=0 hca_object=23
+
+  rdma.events
+       A read-only nested-keyed file which exists on non-root cgroups
+       and contains the following keys:
+
+         max
+               The number of times a process in this cgroup or its
+               descendants attempted an RDMA resource allocation that
+               was rejected because a rdma.max limit in the subtree
+               was reached.  This is a hierarchical counter propagated
+               upward to all ancestor cgroups.  A value change in this
+               file generates a file modified event.
+
+         alloc_fail
+               The number of RDMA resource allocation attempts that
+               originated in this cgroup or its descendants and failed
+               due to a rdma.max limit being reached.  This is a
+               hierarchical counter propagated upward.
+
+       An example for mlx4 device follows::
+
+         mlx4_0 hca_handle.max=5 hca_handle.alloc_fail=3 hca_object.max=0 hca_object.alloc_fail=0
+
+  rdma.events.local
+       Similar to rdma.events but the fields are local to the cgroup,
+       i.e. not hierarchical.  The file modified event generated on this
+       file reflects only the local events.
+
+       The following nested keys are defined.
+
+         max
+               The number of times a process in this cgroup or its
+               descendants attempted an RDMA resource allocation that
+               was rejected because this cgroup's own rdma.max limit
+               was reached.
+
+         alloc_fail
+               The number of RDMA resource allocation attempts
+               originating from this cgroup that failed due to this
+               cgroup's or an ancestor's rdma.max limit.
+
+       An example for mlx4 device follows::
+
+         mlx4_0 hca_handle.max=5 hca_handle.alloc_fail=0 hca_object.max=0 hca_object.alloc_fail=0