Re: [RFC 2/2] cgroup: sev: Miscellaneous cgroup documentation.

Randy Dunlap
2021-02-19T19:04:07Z

Hi,

On 2/18/21 11:55 AM, Vipin Sharma wrote:
> Documentation of miscellaneous cgroup controller. This new controller is
> used to track and limit usage of scalar resources.
>
> Signed-off-by: Vipin Sharma <vipinsh@google.com>
> Reviewed-by: David Rientjes <rientjes@google.com>
> ---
> Documentation/admin-guide/cgroup-v1/misc.rst | 1 +
> Documentation/admin-guide/cgroup-v2.rst | 64 +++++++++++++++++++-
> 2 files changed, 63 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/admin-guide/cgroup-v1/misc.rst
>
> diff --git a/Documentation/admin-guide/cgroup-v1/misc.rst b/Documentation/admin-guide/cgroup-v1/misc.rst
> new file mode 100644
> index 000000000000..8e9e9311daeb
> --- /dev/null
> +++ b/Documentation/admin-guide/cgroup-v1/misc.rst
> @@ -0,0 +1 @@
> +/Documentation/admin-guide/cgroup-v2.rst
What is the purpose of this (above) file?

> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 1de8695c264b..1a41a3623b9b 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -63,8 +63,11 @@ v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst <cgrou
> 5-7-1. RDMA Interface Files
> 5-8. HugeTLB
> 5.8-1. HugeTLB Interface Files
> - 5-8. Misc
> - 5-8-1. perf_event
> + 5-9. Misc
> + 5.9-1 Miscellaneous cgroup Interface Files
> + 5.9-2 Migration and Ownership
> + 5-10. Others
> + 5-10-1. perf_event
> 5-N. Non-normative information
> 5-N-1. CPU controller root cgroup process behaviour
> 5-N-2. IO controller root cgroup process behaviour
> @@ -2161,6 +2164,63 @@ HugeTLB Interface Files
> generated on this file reflects only the local events.
>
> Misc
> +--------------
> +
> +The Miscellaneous cgroup provides the resource allocation and tracking
> +mechanism for the scalar resources which cannot be abstracted like the other
> +cgroup resources. Controller is enabled by the CONFIG_CGROUP_MISC config
> +option.
> +
> +The first two resources added to the miscellaneous controller are Secure
> +Encrypted Virtualization (SEV) ASIDs and SEV - Encrypted State (SEV-ES) ASIDs.
> +These limited ASIDs are used for encrypting virtual machines memory on the AMD
> +platform.
> +
> +Misc Interface Files
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Miscellaneous controller provides 3 interface files:
> +
> + misc.capacity
> + A read-only flat-keyed file shown only in the root cgroup. It shows
> + miscellaneous scalar resources available on the platform along with
> + their quantities::
> + $ cat misc.capacity
> + sev 50
> + sev_es 10
> +
> + misc.current
> + A read-only flat-keyed file shown in the non-root cgroups. It shows
> + the current usage of the resources in the cgroup and its children.::
> + $ cat misc.current
> + sev 3
> + sev_es 0
> +
> + misc.max
> + A read-write flat-keyed file shown in the non root cgroups. Allowed
> + maximum usage of the resources in the cgroup and its children.::
> + $ cat misc.max
> + sev max
> + sev_es 4
> +
> + Limit can be set by::
> + # echo sev 1 > misc.max
> +
> + Limit can be set to max by::
> + # echo sev max > misc.max
> +
> + Limits can be set more than the capacity value in the misc.capacity

higher than

> + file.
> +
> +Migration and Ownership
> +~~~~~~~~~~~~~~~~~~~~~~~
> +
> +A miscellaneous scalar resource is charged to the cgroup in which it is used
> +first, and stays charged to that cgroup until that resource is freed. Migrating
> +a process to a different cgroup do not move the charge to the destination

does

> +cgroup where the process has moved.
> +
> +Others
> ----

That underline is too short for "Others".

>
> perf_event
>

Try building this doc file, please.

next-20210219/Documentation/admin-guide/cgroup-v2.rst:2196: WARNING: Unexpected indentation.
next-20210219/Documentation/admin-guide/cgroup-v2.rst:2203: WARNING: Unexpected indentation.
next-20210219/Documentation/admin-guide/cgroup-v2.rst:2210: WARNING: Unexpected indentation.
next-20210219/Documentation/admin-guide/cgroup-v2.rst:2232: WARNING: Title underline too short.

Others
----
next-20210219/Documentation/admin-guide/cgroup-v2.rst:2232: WARNING: Title underline too short.

I think that the first 3 warnings are due to missing a blank line after ::
or they could have something to do with mixed tabs and spaces in the misc.*
properties descriptions.

thanks.
--
~Randy