Re: [PATCH v1 0/2] mm/kdump: exclude reserved pages in dumps

[Michal Hocko]

On Tue 24-07-18 16:13:09, David Hildenbrand wrote:
[...]
> So I see right now:
> 
> - Pg_reserved + e.g. new page type (or some other unique identifier in
>   combination with Pg_reserved)
>  -> Avoid reads of pages we know are offline
> - extend is_ram_page()
>  -> Fake zero memory for pages we know are offline
> 
> Or even both (avoid reading and don't crash the kernel if it is being done).

I really fail to see how that can work without kernel being aware of
PageOffline. What will/should happen if you run an old kdump tool on a
kernel with this partially offline memory?
-- 
Michal Hocko
SUSE Labs