Messages in this thread | | | From | Muchun Song <> | Date | Mon, 25 Jan 2021 20:31:31 +0800 | Subject | Re: [External] Re: [PATCH v13 09/12] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap |
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On Mon, Jan 25, 2021 at 8:08 PM Oscar Salvador <osalvador@suse.de> 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
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