On Mon, Jan 25, 2021 at 8:08 PM Oscar Salvador <osalvador@xxxxxxx> wrote:
>
> 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:
Yeah, Thanks a lot.
>
> 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
