Hello. On Tue, May 03, 2022 at 12:21:48PM -0400, Waiman Long <longman@xxxxxxxxxx> wrote: > Documentation/admin-guide/cgroup-v2.rst | 145 +++++++++++++----------- > 1 file changed, 79 insertions(+), 66 deletions(-) A note across various lines -- it seems your new text accidentally mixes both spaces and tabs for indentation. > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index 69d7a6983f78..94e1e3771830 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > [...] > + The value shown in "cpuset.cpus.effective" of a partition root is > + the CPUs that the parent partition root can dedicate to the new > + partition root. They are subtracted from "cpuset.cpus.effective" > + of the parent and may be different from "cpuset.cpus" I find this paragraph a bit hard to comprehend (I read it as it talks about three levels of cgroups (parent, child, grandparent). It is correct but I'd suggect following formulation (where I additionally simplifed it by talking about "available" cpus): > The value shown in "cpuset.cpus.effective" of a partition root is > the CPUs that the partition root can dedicate to a potential new child > partition root. The new child subtracts available CPUs from its parent > "cpuset.cpus.effective". > + For a partition root to become valid, the following conditions > + must be met. > + > + 1) The "cpuset.cpus" is exclusive, i.e. they are not shared by > + any of its siblings (exclusivity rule). > + 2) The parent cgroup is a valid partition root. > + 3) The "cpuset.cpus" is not empty and must contain at least > + one of the CPUs from parent's "cpuset.cpus", i.e. they overlap. > + 4) The "cpuset.cpus.effective" must be a subset of "cpuset.cpus" > + and cannot be empty unless there is no task associated with > + this partition. This sounds good to me. > + Care must be taken to change a valid partition root to "member" > + as all its child partitions, if present, will become invalid. This does not talk about recovering. Is it intentional? (I.e. to left implementation defined) Except the remarks above, I find the concepts described here good. I'll reply to implementation separately & later. Regards, Michal
