Messages in this thread | | | Date | Fri, 25 Apr 2008 13:21:05 +0200 | From | Gabriel C <> | Subject | Re: [REGRESSION] x86: support for new UV apic |
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Andi Kleen wrote: > Ingo Molnar <mingo@elte.hu> writes: > >> * Priit Laes <plaes@plaes.org> wrote: >> >>> Hey, >>> >>> I am getting two following warnings (probable one per each CPU core) >>> using the latest Linus's git: >>> >>> WARNING: at arch/x86/kernel/genapic_64.c:86 read_apic_id+0x30/0x62() >>> Modules linked in: >>> Pid: 1, comm: swapper Not tainted 2.6.25-03563-gf7288b1 #20 >> thanks - could you check the patch below, does it fix the warnings? > > I think it would have been better to change the WARN_ON to > > WARN_ON(preemptible() && num_online_cpus() > 1)
Hmm , I think you are right , Ingo's patch fixes the warning on boot but now I get one when I reboot the box.
> > Preemption is actually ok here because this runs before the other > CPUs are started > > Alternative patch appended.
I will test your patch in some minutes.
> > -Andi
Gabriel
> > --- > > Don't warn in read_apic_id() when preemptible but only one CPU online. > > Signed-off-by: Andi Kleen <andi@firstfloor.org> > > Index: linux/arch/x86/kernel/genapic_64.c > =================================================================== > --- linux.orig/arch/x86/kernel/genapic_64.c > +++ linux/arch/x86/kernel/genapic_64.c > @@ -83,7 +83,7 @@ unsigned int read_apic_id(void) > { > unsigned int id; > > - WARN_ON(preemptible()); > + WARN_ON(preemptible() && num_online_cpus() > 1); > id = apic_read(APIC_ID); > if (uv_system_type >= UV_X2APIC) > id |= __get_cpu_var(x2apic_extra_bits);
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