Re: [Patch] x86: fix smp_num_siblings on buggy BIOSes

From: Siddha, Suresh B
Date: Fri May 27 2005 - 01:39:10 EST


On Thu, May 26, 2005 at 10:17:37PM -0700, Andrew Morton wrote:
> "Siddha, Suresh B" <suresh.b.siddha@xxxxxxxxx> wrote:
> >
> > Appended patch will fix 'smp_num_siblings' value on the systems with
> > buggy bios, which sets number of siblings to '2' even when HT is disabled.
> > (more details are at http://bugzilla.kernel.org/show_bug.cgi?id=4359)
> >
> > I am planning to do more cleanup in this area (like moving smp_num_siblings
> > to per cpuinfo) shortly.
> >
> > But meanwhile, please pickup this patch for 2.6.12.
> >
> > Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
> > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
> >
> > --- linux-2.6.12-rc5/arch/i386/kernel/smpboot.c~ 2005-05-25 16:47:56.462416368 -0700
> > +++ linux-2.6.12-rc5/arch/i386/kernel/smpboot.c 2005-05-25 16:48:14.556665624 -0700
> > @@ -1074,8 +1074,10 @@
> > cpu_set(cpu, cpu_sibling_map[cpu]);
> > }
> >
> > - if (siblings != smp_num_siblings)
> > + if (siblings != smp_num_siblings) {
> > printk(KERN_WARNING "WARNING: %d siblings found for CPU%d, should be %d\n", siblings, cpu, smp_num_siblings);
> > + smp_num_siblings = siblings;
> > + }
> >
> > if (c->x86_num_cores > 1) {
> > for (i = 0; i < NR_CPUS; i++) {
>
> OK, but be aware that -mm's sibling-map-initializing-rework.patch
> cheerfully deletes all the surrounding code. So -mm will not have this
> fix.
>
> There's a completely loony amount of x86 stuff in -mm.

Thanks for this info. I will send a fix for -mm also.

BTW, when do you plan to integrate x86 cpu hotplug patches to mainline?
Depending on that I will plan my "smp_num_siblings" global cleanup.

thanks,
suresh
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