From: David Hildenbrand on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1023#note_5541...
Right, if the user manually specifies "cma=2G" and the system is not
able to cope with that, this is a clear configuration error and once
supported, we would want to document that -- there are other cases where
having too much CMA memory can be problematic.
Regarding s390x/cma: they reserve other CMA regions, not the default one
(cmd=XX); we'd want to specify:
- vmcp_cma=0 on s390x
- kvm_cma_resv_ratio=0 on ppc64
However, the s390x version is not too bad (-> 4 MiB), so maybe we want
to leave that untouched.