On 11/01/22 8:06 pm, David Hildenbrand wrote:
On 06.01.22 13:01, Hari Bathini wrote:
To answer the question, fadump does not want the memory to be used for
kernel pages, if CMA activation fails...
Okay, so what you want is a reserved region, and if possible, let CMA
use that memory for other (movable allocation) purposes until you
actually need that area and free it up by using CMA. If CMA cannot use
the region because of zone issues, you just want that region to stay
reserved.
Right.
I guess the biggest different to other CMA users is that it can make use
of the memory even if not allocated via CMA -- because it's going to
make use of the the physical memory range indirectly via a HW facility,
not via any "struct page" access.
I wonder if we can make the terminology a bit clearer, the freeing part
is a bit confusing, because init_cma_reserved_pageblock() essentially
also frees pages, just to the MIGRATE_CMA lists ... what you want is to
treat it like a simple memblock allocation/reservation on error.
What about:
* cma->reserve_pages_on_error that defaults to false
* void __init cma_reserve_pages_on_error(struct cma *cma)
Yeah, this change does make things bit more clearer.
Will send out a v2 with the change..
