[PATCH v2 0/5] kdump: crashkernel reservation from CMA

[Michal Hocko]

On Wed 28-05-25 23:01:04, David Hildenbrand wrote:
[...]
> I think we just have to be careful to document it properly -- especially the
> shortcomings and that this feature might become a problem in the future.
> Movable user-space page tables getting placed on CMA memory would probably
> not be a problem if we don't care about ... user-space data either way.

I think makedumpfile could refuse to capture a dump if userspace memory
is requested to enforce this.

> The whole "Direct I/O takes max 1s" part is a bit shaky. Maybe it could be
> configurable how long to wait? 10s is certainly "safer".

Quite honestly we will never know and rather than making this
configurable I would go with reasonably large. Couple of seconds
certainly do not matter for the kdump situations but I would go as far
as minutes.

-- 
Michal Hocko
SUSE Labs