(2014/01/10 6:44), Vivek Goyal wrote: > On Thu, Jan 09, 2014 at 04:34:16PM -0500, KOSAKI Motohiro wrote: >> On Thu, Jan 9, 2014 at 10:00 AM, Vivek Goyal <vgoyal at redhat.com> wrote: >>> On Thu, Jan 09, 2014 at 12:00:29AM +0100, Rafael J. Wysocki wrote: >>> >>> [..] >>>>> The system then panics and the kdump/kexec kernel boots. During this boot >>>>> ACPi is initialized and the kernel (as can be seen above) >>>> >>>> Which is a bug. You're not supposed to initialize ACPI twice in a row. >>> >>> [CC lkml, kexec mailing list, dave young] >>> >>> It is a fresh instance of kernel booting and it is initializing its data >>> structures fresh. It is *not* re-initializing ACPI in same kernel. >>> >>>>> This patchset resolves the problem by adding a kernel parameter, >>>>> no_memory_hotplug, to disable ACPI memory hotplug. It can be added by default >>>>> as a parameter to the kexec/kdump kernel so the kernel boots correctly. >>>> >>>> This problem is specific to kexec/kdump, so please don't add *generic* command >>>> line parameters to address this. >>>> >>> >>> There are other command line options to solve kdump problems. In general >>> one might want to disable memory hogplug on the fly even if it is compiled >>> in the kernel. So it can act as a good debugging aid. >>> >>> Secondly, it can be specified with memmap=exactmap and mem=X paramters to >>> make sure no memory is hot added in the system. >>> >>> So I can see other usages of this parameter. To me it makes sense to have >>> a separate command line option to disable memory hotplug feature on the >>> fly. >> >> I'm ok this option. But note, even if this option is specified, SH, >> Power and S390 still >> be able to use memory hotplug because their firmware are totally >> different from ACPI. >> >> Maybe, adding acpi prefix provides good clarification. > > Makes sense. Something like "acpi_no_memhotplug" or "acpi_disable_memhotplug" > or something else. I like Prarit's patch and the boot option name. If it is updated, I'll test it. Thanks, Yasuaki Ishimatsu > > Thanks > Vivek > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
