Re: [TIP,BISECTED] Negative nice values have become big positivenumbers

From: Ingo Molnar
Date: Mon Mar 09 2009 - 03:09:01 EST



* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Sun, 8 Mar 2009, Sitsofe Wheeler wrote:
>
> > (Forgot to cc lkml. Resending...)
> >
> > Formally negative nice values have started become very big in positive
> > integers in -tip kernels:
> >
> > 2 root 15 2147483647 0 0 0 S 0.0 0.0 0:00.00 kthreadd
>
> Is this the output of top?

seems so.

> > I've just finished bisecting down to this commit:
> >
> > commit 1427cdf0592368bdec57276edaf714040ee8744f
> > Author: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> > Date: Fri Mar 6 17:21:47 2009 +0100
>
> $ git show 1427cdf0592368bdec57276edaf714040ee8744f | diffstat
> include/linux/ftrace.h | 3 +
> kernel/trace/Kconfig | 6 ++
> kernel/trace/Makefile | 1
> kernel/trace/trace.c | 56 +++++++++++++++++++++++++++
> kernel/trace/trace.h | 12 +++++
> kernel/trace/trace_bprintk.c | 87
> +++++++++++++++++++++++++++++++++++++++++++
> kernel/trace/trace_output.c | 75 +++++++++++++++++++++++++++++++++++++
> 7 files changed, 240 insertions(+)
>
> I find it hard to believe that this would cause normal nice
> values to be messed up. The only file that could could come
> close to messing with nice values in top is ftrace.h:

Correct - maybe it's these two nearby commits that cause the
problems:

fef20d9: vsprintf: unify the format decoding layer for its 3 users
4370aa4: vsprintf: add binary printf

they do affect generic code. If we broke vsnprintf (which the
nice value output code uses) then that might be a plausible
explanation.

Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/