RE: [PATCH][RFC] mm: Introduce kernelcore=reliable option

From: Luck, Tony
Date: Mon Oct 12 2015 - 14:43:37 EST


> If we reuse the movable zone, we should set appropriate size of
> mirrored memory region(normal zone) and non-mirrored memory
> region(movable zone). In some cases, kernel will take more memory
> than user, e.g. some apps run in kernel space, like module.
>
> I think user can set the size in BIOS interface, right?

Exact methods may vary as different BIOS vendors implement things the way
they like (or the way an OEM asks them). In the Intel reference BIOS you can either
set an explicit mirror size for each memory controller, or you can have the BIOS
look at some EFI boot variables to find a percentage of memory to use spread
across all memory controllers.

See:
https://software.intel.com/sites/default/files/managed/43/6a/Memory%20Address%20Range%20Mirroring%20Validation%20Guide.pdf

There are patches to efibootmgr(8) to set/show the EFI variables:
git://github.com/rhinstaller/efibootmgr

-Tony




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