Re: [PATCH] x86_64: early memtest to find bad ram

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Fri, Mar 21, 2008 at 2:22 PM, Jan Engelhardt <jengelh@computergmbh.de> wrote:
>
>  On Mar 21 2008 13:03, Ingo Molnar wrote:
>  > * Yinghai Lu <yhlu.kernel.send@gmail.com> wrote:
>  >
>  >> do simple memtest after init_memory_mapping
>  >> use find_e820_area_size to find all ram range that is not reserved.
>  >> and do some simple bits test to find some bad ram.
>  >> if find some bad ram, use reserve_early to exclude that range.
>  >
>  > very nice patch! I always thought that this was the proper way to do
>  > memtest - and we could in fact also do something like this after SMP
>  > bringup, and hit the memory bus via multiple CPUs. [that will need a
>  > different enumeration though than e820 maps]
>
>  Perhaps this can even be used to provide on-the-fly badram
>  patch semantics?

yes. but bad ranges can not be too many. otherwise early_res array
will overflow. then need to use memmap=nn$ss to exclude range already
found.

YH