Re: [Lse-tech] Re: CPUSET Proposal

[William Lee Irwin III <wli@holomorphy.com>]

At some point in the past, someone wrote:
>> BTW: What do cpusets provide that couldn't be done with user-level
>> tools on top of the existing sched_setaffinity() system call?

On Wed, Sep 24, 2003 at 10:39:44PM -0700, Paul Jackson wrote:
> I don't see how you can do the migrate_cpuset_processes() from a user
> level daemon.  Just because two tasks happen to be allowed on the same
> CPUs doesn't mean they are in the same cpuset.  The kernel must track,
> across forks, which tasks share a given cpuset.
> There are also some resource management capabilities, such as tracking
> and controlling how much memory a cpuset takes, and swapping (with
> possible oom kill) against a cpuset that one can consider extending this
> to, but only if it's in the kernel.  But I'm not ready to push this
> point ... yet.
> And the permission model has to remain a rather primitive "root can do
> anything, anyone else can just subset their parent" if it lacks kernel
> hooks to track uid/suid ownership of each cpuset.

This sounds like it has progressively more commonality with CKRM; the
notion is of a workclass, not of a purely cpu-oriented notion.


-- wli