On Mon, Jan 25, 2021 at 12:43:23PM +0100, David Hildenbrand wrote:
> > - if (end - start < PAGES_PER_SECTION * sizeof(struct page))
> > + if (is_hugetlb_free_vmemmap_enabled() ||
> > + end - start < PAGES_PER_SECTION * sizeof(struct page))
>
> This looks irresponsible. You ignore any altmap, even though current
> altmap users (ZONE_DEVICE) will not actually result in applicable
> vmemmaps that huge pages could ever use.
>
> Why do you ignore the altmap completely? This has to be properly
> documented, but IMHO it's not even the right approach to mess with
> altmap here.
The goal was not to ignore altmap but to disable PMD mapping sections
when the feature was enabled.
Shame on me I did not notice that with this, altmap will be ignored.
Something like below maybe:
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
struct vmem_altmap *altmap)
{
int err;
bool populate_base_pages = false;
if ((end - start < PAGES_PER_SECTION * sizeof(struct page)) ||
(is_hugetlb_free_vmemmap_enabled() && !altmap))
populate_base_pages = true;
if (populate_base_pages) {
err = vmemmap_populate_basepages(start, end, node, NULL);
} else if (boot_cpu_has(X86_FEATURE_PSE)) {
....
>
> --
> Thanks,
>
> David / dhildenb
>
>
--
Oscar Salvador
SUSE L3
