I payed attention to the appearance, beause my host start and trigger the
following code and printk logs
printk("%sAPIC ID %#x and/or ACPI ID %#x beyond limit"
" - processor ignored\n",
processor->lapic_flags & ACPI_MADT_ENABLED ?
KERN_WARNING "WARNING: " : KERN_INFO,
processor->local_apic_id, processor->uid);
after refered to the below comment in function acpi_parse_x2apic of xen latest
version
/*
* We need to register disabled CPU as well to permit
* counting disabled CPUs. This allows us to size
* cpus_possible_map more accurately, to permit
* to not preallocating memory for all NR_CPUS
* when we use CPU hotplug.
*/
mp_register_lapic(processor->local_apic_id, enabled, 0);
and compared with linux4.1 function acpi_parse_x2apic,
this patch will be useful if xen host support CPU hotplug in the future,
-----邮件原件-----
发件人: Jan Beulich [mailto:jbeul...@suse.com]
发送时间: 2015年7月7日 15:54
收件人: Fanhenglong
抄送: Hanweidong (Randy); Huangpeng (Peter); Yanqiangjun; xen-devel@lists.xen.org
主题: Re: [Xen-devel] [PATCH]xen new latest version mp_register_lapic can't
register disabled CPU, patch attempt to fix
>>> On 07.07.15 at 01:52, <fanhengl...@huawei.com> wrote:
> When xen booted up and parsed all cpus by acpi_parse_x2apic,
>
> if the number of "Processor Local x2APIC Structure"(struct
> acpi_madt_local_x2apic) parsed from acpi table bigger than the number
>of host cpu.
> for all extra acpi_madt_local_x2apic structure, struct
>acpi_madt_local_x2apic {
> struct acpi_subtable_header header;
> u16 reserved; /* Reserved - must be zero */
> u32 local_apic_id; /* Processor x2APIC ID */
> u32 lapic_flags;
> u32 uid; /* ACPI processor UID */
> };
> member local_apic_id has default value FFFFFFFF.
>[...]
> based on the above code, "processor->local_apic_id >=
>MAX_APICS"(line:103) and return ,caused each disabled CPU can't be registered.
But you fail to explain why you think these processors need to be registered.
They're disabled after all.
Jan
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