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    SubjectRe: sched: Move SCHED_DEBUG sysctl to debugfs
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    On 27.04.21 17:09, Steven Rostedt wrote:
    > On Tue, 27 Apr 2021 16:59:25 +0200
    > Christian Borntraeger <borntraeger@de.ibm.com> wrote:
    >
    >> Peter,
    >>
    >> I just realized that we moved away sysctl tunabled to debugfs in next.
    >> We have seen several cases where it was benefitial to set
    >> sched_migration_cost_ns to a lower value. For example with KVM I can
    >> easily get 50% more transactions with 50000 instead of 500000.
    >> Until now it was possible to use tuned or /etc/sysctl.conf to set
    >> these things permanently.
    >>
    >> Given that some people do not want to have debugfs mounted all the time
    >> I would consider this a regression. The sysctl tunable was always
    >> available.
    >>
    >> I am ok with the "informational" things being in debugfs, but not
    >> the tunables. So how do we proceed here?
    >
    > Should there be a schedfs created?
    >
    > This is the reason I created the tracefs file system, was to get the
    > tracing code out of debugfs, as debugfs is a catch all for everything and
    > can lead to poor and insecure interfaces that people do not want to add on
    > systems that they still want tracing on.
    >
    > Or perhaps we should add a "tunefs" for tunables that are stable interfaces
    > that should not be in /proc but also not in debugfs.

    Yes, a tunefs or schedfs could be considered a replacement for sysctl.
    It will still break existing setups with kernel.sched* things in /etc/sysctl.conf
    but at least there is a stable transition path.


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