Messages in this thread | | | Date | Tue, 27 Sep 2011 16:42:19 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] i386/bigsmp: eliminate false warnings regarding logical APIC ID mismatches |
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* Jan Beulich <JBeulich@suse.com> wrote:
> >>> On 27.09.11 at 15:35, Ingo Molnar <mingo@elte.hu> wrote: > > > * Jan Beulich <JBeulich@novell.com> wrote: > > > >> These warnings (generally one per CPU) are a result of initializing > >> x86_cpu_to_logical_apicid while apic_default is still in use, but the > >> check in setup_local_APIC() being done when apic_bigsmp was already > >> used as an override in default_setup_apic_routing(): > >> > >> Overriding APIC driver with bigsmp > >> Enabling APIC mode: Physflat. Using 5 I/O APICs > >> ------------[ cut here ]------------ > >> WARNING: at .../arch/x86/kernel/apic/apic.c:1239 > > setup_local_APIC+0x137/0x46b() > >> Hardware name: ... > >> CPU0 logical APIC ID: 1 != 0 > >> Pid: 1, comm: swapper Not tainted 3.0.1-2011-08-09-jb #2 > >> Call Trace: > >> [<c1005f91>] try_stack_unwind+0x1b1/0x1f0 > >> [<c1004cc7>] dump_trace+0x47/0x110 > >> [<c1005b0b>] show_trace_log_lvl+0x4b/0x60 > >> [<c1005b38>] show_trace+0x18/0x20 > >> [<c1261435>] dump_stack+0x6d/0x72 > >> [<c10355f7>] warn_slowpath_common+0x77/0xb0 > >> [<c10356c3>] warn_slowpath_fmt+0x33/0x40 > >> [<c13fda81>] setup_local_APIC+0x137/0x46b > >> [<c13d1733>] native_smp_prepare_cpus+0x108/0x1cd > >> [<c13c61ff>] kernel_init+0x37/0x12c > >> [<c1264826>] kernel_thread_helper+0x6/0xd > >> ---[ end trace 4eaa2a86a8e2da22 ]--- > >> ... > >> CPU 1 irqstacks, hard=f1c9a000 soft=f1c9c000 > >> Booting Node 0, Processors #1 > >> smpboot cpu 1: start_ip = 9e000 > >> Initializing CPU#1 > >> ------------[ cut here ]------------ > >> WARNING: at .../arch/x86/kernel/apic/apic.c:1239 > > setup_local_APIC+0x137/0x46b() > >> Hardware name: ... > >> CPU1 logical APIC ID: 2 != 8 > >> ... > >> > >> Fix this (for the time being, i.e. until x86_32_early_logical_apicid() > >> will get removed again, as Tehun says ought to be possible) by > >> overriding the previously stored values at the point where the APIC > >> driver gets overridden. > >> > >> Signed-off-by: Jan Beulich <jbeulich@novell.com> > >> Cc: Tejun Heo <tj@kernel.org> > >> Cc: stable@kernel.org (2.6.39 and onwards) > >> > >> --- > >> arch/x86/kernel/apic/probe_32.c | 11 +++++++++++ > >> 1 file changed, 11 insertions(+) > >> > >> --- 3.1-rc2/arch/x86/kernel/apic/probe_32.c > >> +++ 3.1-rc2-i386-bigsmp-early-lapicid-override/arch/x86/kernel/apic/probe_32.c > >> @@ -203,7 +203,18 @@ void __init default_setup_apic_routing(v > >> if (!cmdline_apic && apic == &apic_default) { > >> struct apic *bigsmp = generic_bigsmp_probe(); > >> if (bigsmp) { > >> + unsigned int cpu; > >> + > >> apic = bigsmp; > >> + for_each_possible_cpu(cpu) { > >> + if (early_per_cpu(x86_cpu_to_logical_apicid, > >> + cpu) == BAD_APICID) > >> + continue; > >> + early_per_cpu(x86_cpu_to_logical_apicid, > >> + cpu) = > >> + bigsmp->x86_32_early_logical_apicid > >> + (cpu); > >> + } > >> printk(KERN_INFO "Overriding APIC driver with %s\n", > >> apic->name); > >> } > > > > This could move into a separate function i suspect, which would > > de-uglify it quite significantly? > > If that's the only concern, then sure - I'll re-submit with this broken out.
Yeah, i think it would be fine that way. If you think there's a chance of something breaking or complaints coming up then you can split it into two patches: the first one factors out the function, the second one does the change.
Thanks,
Ingo
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