Messages in this thread | | | Date | Fri, 30 Sep 2022 19:40:35 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v12 7/7] x86/crash: Add x86 crash hotplug support |
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On Fri, Sep 30, 2022 at 12:11:26PM -0500, Eric DeVolder wrote: > There is of course a way to enumerate the memory regions in use on the > machine, that is not what this code needs. In order to compute the maximum > buffer size needed (this buffer size is computed once), the count of the > maximum number of memory regions possible (even if not currently in use) is > what is needed.
Isn't that max number documented somewhere in memory hotplug docs?
Because then you don't need that Kconfig item either. Imagine you're a distro kernel distributor and you want crash to work on all machines your kernel works.
So you go and set that number to max. And that would be the 99% of the kernel configs out there.
Which means, you can just set it to max without a Kconfig item.
> Oh, that would be an error of haste on my part. This should be: > depends on CRASH_DUMP && MEMORY_HOTPLUG
You need a Kconfig item which enables all this gunk as MEMORY_HOTPLUG is not a omnipresent feature. And that Kconfig item should depend on the other Kconfig items of the technology you need.
> Baoquan pointed me to: > > https://lore.kernel.org/lkml/cover.1656659357.git.naveen.n.rao@linux.vnet.ibm.com/T/
In that thread says:
"- arch_kexec_apply_relocations_add() is only overridden by x86 and s390. Retain the function prototype for those and move the weak implementation into the header as a static inline for other architectures."
So yes, that's even better.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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