Re: [PATCH v5 08/24] sched: Introduce per memory space current virtual cpu id

[Andy Lutomirski]

On Thu, Nov 3, 2022 at 1:05 PM Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
> This feature allows the scheduler to expose a current virtual cpu id
> to user-space. This virtual cpu id is within the possible cpus range,
> and is temporarily (and uniquely) assigned while threads are actively
> running within a memory space. If a memory space has fewer threads than
> cores, or is limited to run on few cores concurrently through sched
> affinity or cgroup cpusets, the virtual cpu ids will be values close
> to 0, thus allowing efficient use of user-space memory for per-cpu
> data structures.
>

Just to check, is a "memory space" an mm?  I've heard these called
"mms" or sometimes (mostly accurately) "processes" but never memory
spaces.  Although I guess the clone(2) manpage says "memory space".

Also, in my mind "virtual cpu" is vCPU, which this isn't.  Maybe
"compacted cpu" or something?  It's a strange sort of concept.