diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 098d6831b3c0..91beaa6798ce 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -737,9 +737,6 @@ combinations are invalid and should be rejected. Also, if the resource is mandatory for execution of processes, process migrations may be rejected. -"cpu.rt.max" hard-allocates realtime slices and is an example of this -type. - Interface Files =============== @@ -2561,10 +2558,10 @@ Cpuset Interface Files Users can manually set it to a value that is different from "cpuset.cpus". One constraint in setting it is that the list of CPUs must be exclusive with respect to "cpuset.cpus.exclusive" - of its sibling. If "cpuset.cpus.exclusive" of a sibling cgroup - isn't set, its "cpuset.cpus" value, if set, cannot be a subset - of it to leave at least one CPU available when the exclusive - CPUs are taken away. + and "cpuset.cpus.exclusive.effective" of its siblings. Another + constraint is that it cannot be a superset of "cpuset.cpus" + of its sibling in order to leave at least one CPU available to + that sibling when the exclusive CPUs are taken away. For a parent cgroup, any one of its exclusive CPUs can only be distributed to at most one of its child cgroups. Having an @@ -2584,9 +2581,9 @@ Cpuset Interface Files of this file will always be a subset of its parent's "cpuset.cpus.exclusive.effective" if its parent is not the root cgroup. It will also be a subset of "cpuset.cpus.exclusive" - if it is set. If "cpuset.cpus.exclusive" is not set, it is - treated to have an implicit value of "cpuset.cpus" in the - formation of local partition. + if it is set. This file should only be non-empty if either + "cpuset.cpus.exclusive" is set or when the current cpuset is + a valid partition root. cpuset.cpus.isolated A read-only and root cgroup only multiple values file. @@ -2618,13 +2615,22 @@ Cpuset Interface Files There are two types of partitions - local and remote. A local partition is one whose parent cgroup is also a valid partition root. A remote partition is one whose parent cgroup is not a - valid partition root itself. Writing to "cpuset.cpus.exclusive" - is optional for the creation of a local partition as its - "cpuset.cpus.exclusive" file will assume an implicit value that - is the same as "cpuset.cpus" if it is not set. Writing the - proper "cpuset.cpus.exclusive" values down the cgroup hierarchy - before the target partition root is mandatory for the creation - of a remote partition. + valid partition root itself. + + Writing to "cpuset.cpus.exclusive" is optional for the creation + of a local partition as its "cpuset.cpus.exclusive" file will + assume an implicit value that is the same as "cpuset.cpus" if it + is not set. Writing the proper "cpuset.cpus.exclusive" values + down the cgroup hierarchy before the target partition root is + mandatory for the creation of a remote partition. + + Not all the CPUs requested in "cpuset.cpus.exclusive" can be + used to form a new partition. Only those that were present + in its parent's "cpuset.cpus.exclusive.effective" control + file can be used. For partitions created without setting + "cpuset.cpus.exclusive", exclusive CPUs specified in sibling's + "cpuset.cpus.exclusive" or "cpuset.cpus.exclusive.effective" + also cannot be used. Currently, a remote partition cannot be created under a local partition. All the ancestors of a remote partition root except @@ -2632,6 +2638,10 @@ Cpuset Interface Files The root cgroup is always a partition root and its state cannot be changed. All other non-root cgroups start out as "member". + Even though the "cpuset.cpus.exclusive*" and "cpuset.cpus" + control files are not present in the root cgroup, they are + implicitly the same as the "/sys/devices/system/cpu/possible" + sysfs file. When set to "root", the current cgroup is the root of a new partition or scheduling domain. The set of exclusive CPUs is |