Messages in this thread | | | From | "Wei, Jiangang" <> | Subject | Re: [PATCH 1/2] x86/smpboot: Check APIC ID before setting up default routing | Date | Thu, 18 Aug 2016 10:15:15 +0000 |
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On Thu, 2016-08-18 at 11:47 +0200, Ingo Molnar wrote: > * Wei Jiangang <weijg.fnst@cn.fujitsu.com> wrote: > > > Check the boot APIC ID firstly, > > and then setup the default routing of APIC looks better. > > > > And move default_setup_apic_routing() close to apic_bsp_setup(), > > which staying in step with the codes in APIC_init_uniprocessor(). > > > > Signed-off-by: Wei Jiangang <weijg.fnst@cn.fujitsu.com> > > --- > > arch/x86/kernel/smpboot.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > If it's not a bug then please clearly note so in the changelog and > explain why the change results in better code.
It's not a bug. The combination of default_setup_apic_routing() and apic_bsp_setup() is used to enable APIC mode. If the return of read_apic_id() is not equal to boot_cpu_physical_apicid, it means the APIC ID of current CPU‘s local APIC is unexpected and enable APIC mode maybe fail. so no need to set up the apic routing. That's why I want to move default_setup_apic_routing() behind checking the boot APIC ID.
Sorry for obscure commit message. I will improve it in next version.
> > If it's fixing a bug/misfeature then please fix the changelog to > conform to the standard changelog style: > > - first describe the symptoms of the bug - how does a user notice? > > - then describe how the code behaves today and how that is causing the bug > > - and then only describe how it's fixed.
Thanks for your detailed explanation. I'll keep in my mind. > > Thanks, > > Ingo > >
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