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

From: Mike Galbraith
Date: Sat Dec 12 2009 - 01:07:59 EST


On Fri, 2009-12-11 at 21:55 -0800, Arve HjÃnnevÃg 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.

-Mike

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