Re: [tip:sched/urgent] sched: Set correct normal_prio and priovalues in sched_fork()

From: Ingo Molnar
Date: Sat Dec 12 2009 - 01:18:32 EST



* Mike Galbraith <efault@xxxxxx> wrote:

> On Fri, 2009-12-11 at 21:55 -0800, Arve Hj??nnev??g wrote:
> > On Mon, Oct 5, 2009 at 3:47 AM, tip-bot for Peter Williams
> > <pwil3058@xxxxxxxxxxxxxx> wrote:
> > > Commit-ID: f83f9ac2632732bd1678150b5a03d152f912fe72
> > > Gitweb: http://git.kernel.org/tip/f83f9ac2632732bd1678150b5a03d152f912fe72
> > > Author: Peter Williams <pwil3058@xxxxxxxxxxxxxx>
> > > AuthorDate: Thu, 24 Sep 2009 06:47:10 +0000
> > > Committer: Ingo Molnar <mingo@xxxxxxx>
> > > CommitDate: Mon, 5 Oct 2009 13:42:20 +0200
> > >
> > > sched: Set correct normal_prio and prio values in sched_fork()
> > >
> > > normal_prio should be updated if policy changes from RT to
> > > SCHED_MORMAL or if static_prio/nice is changed.
> > >
> > > Some paths through sched_fork() ignore this requirement and may
> > > result in normal_prio having an invalid value.
> > >
> > > Fixing this issue allows the call to effective_prio() in
> > > wake_up_new_task() to be removed.
> > >
> >
> > This change causes a lot of threads with a 0 nice value to get a prio
> > value of 140 instead of 120 (at least on my android arm msm build). I
> > don't know if this has any impact on how they are scheduled since the
> > load weight is unaffected, but it at least makes the output of ps more
> > confusing.
>
> There's a patch in tip to correct this, hasn't swam upstream yet.

just sent the pull request to Linus for the latest scheduler fixes.
Meanwhile you can try latest -tip with the fix:

http://people.redhat.com/mingo/tip.git/README

Ingo
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