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    SubjectRe: [PATCH 10/16] sched: add resource limits for -deadline tasks.
    On 04/24/2012 05:07 PM, Peter Zijlstra wrote:
    > On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote:
    >> From: Dario Faggioli<>
    >> Add resource limits for non-root tasks in using the SCHED_DEADLINE
    >> policy, very similarly to what already exists for RT policies.
    >> In fact, this patch:
    >> - adds the resource limit RLIMIT_DLDLINE, which is the minimum value
    >> a user task can use as its own deadline;
    >> - adds the resource limit RLIMIT_DLRTIME, which is the maximum value
    >> a user task can use as it own runtime.
    >> Notice that to exploit these, a modified version of the ulimit
    >> utility and a modified resource.h header file are needed. They
    >> both will be available on the website of the project.
    >> Signed-off-by: Dario Faggioli<>
    >> Signed-off-by: Juri Lelli<>
    > I'm not sure this is the right way to go.. those existing things aren't
    > entirely as useful/sane as one might hope either.
    > The DLDLINE minimum is ok I guess, the DLRTIME one doesn't really do
    > anything, by spawning multiple tasks one can still saturate the cpu and
    > thus we have no effective control for unpriv users.
    > Ideally DLRTIME would be a utilization cap per user and tracked in
    > user_struct such that we can enforce a max utilization per user.
    > This also needs a global (and possibly per-cgroup) user limit too to cap
    > the total utilization of all users (excluding root) so that multiple
    > users cannot combine their efforts in order to bring down the machine.
    > In light of these latter controls the per-user control might be
    > considered optional, furthermore I don't particularly like the rlimit
    > infrastructure but I guess its the best we have for per-user like things
    > if indeed we want to go there.

    Ok, but considering what you said regarding setscheduler security problems:

    On 04/24/2012 11:00 AM, Peter Zijlstra wrote:
    > On Tue, 2012-04-24 at 09:21 +0200, Juri Lelli wrote:
    >> > Well, depends on how much effort will this turn to require. I personally
    >> > would prefer to be able to come out with a new release ASAP. Just to
    >> > continue the discussion with the most of the comments addressed and a
    >> > more updated code (I also have a mainline version of the patchset
    >> > quite ready).
    > Right, one thing we can initially do is require root for using
    > SCHED_DEADLINE and then when later work closes all the holes and we've
    > added user bandwidth controls we can allow everybody in.

    Are you suggesting to drop/postpone this to some later time?


    - Juri

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