Re: [lhcs-devel] Re: support for userspace ppc64 tools

[<js...@au...>]

Hmmm...  Well, at least keep this bit of the patch, which keeps us from
trying to boot cpus that aren't present.

@@ -985,6 +999,12 @@
 {
        int c;

+       /* If we are doing the initial boot we need to check the possible
cpus
+        * to make sure they are really there.  -JSCHOPP
+        */
+       if(!system_running && !cpu_present_at_boot(cpu))
+           return -EINVAL;
+
        paca[cpu].prof_counter = 1;
        paca[cpu].prof_multiplier = 1;
        paca[cpu].default_decr = tb_ticks_per_jiffy / decr_overclock;


On Sun, 22 Feb 2004, Rusty Russell wrote:
> > The second patch (below) is support for dyamically adding properties to
> > nodes in the open firmware device tree located in /proc.  It is my opinion
> > this should go into a mainline kernel.  This work originated with Nathan
> > Lynch.  This is necessary for the userspace tools to map the physical to
> > logical cpuid.
>
> This is a mistake on 2.6, on several levels.
>
> 1) No other code dynamically alters the OF tree after boot.
>
> 2) It's buggy: the locking is just wrong.  The true patch would be
>    bigger.

/proc itself is buggy, I don't see how this makes it much worse.

>
> 3) Other architectures need a similar mapping, and putting this in
>    sysfs gives us an arch-independent method.
>

Here is the crux of the debate.  If time were an infinate commodity I
might agree with you.  Come to think of it the whole /proc device tree
would be better served in /sys.  My personal goal right now is to get
something "good enough" out so real end users can actually hotplug cpus
and dynamically partition their machines.

> 4) The sysfs code is already in Ameslab.

And the /proc code is already in the tools.

>
> Nathan: who is relying on this?

drslot_chrp_cpu is the command relying on this I believe.

>
> Cheers,
> Rusty.
> --
>   Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
>
>
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