Messages in this thread | | | Date | Wed, 17 Mar 2021 10:43:53 +0100 | From | Oscar Salvador <> | Subject | Re: [PATCH v4 0/4] Make alloc_contig_range handle Hugetlb pages |
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On 2021-03-15 10:06, David Hildenbrand wrote: > BTW, I stumbled yesterday over > > alloc_contig_pages()->pfn_range_valid_contig(): > > if (page_count(page) > 0) > rerurn false; > if (PageHuge(page)) > return false; > > As used by memtrace and for gigantic pages. We can now > > a) Drop these check completely, as it's best-effort only and racy. > alloc_contig_pages()/alloc_contig_range() will handle it properly.
I was preparing v5, and I wanted to be sure I understood you here.
Right you are that the in-use page check can be dropped, as those pages can be migrated away, and the Hugetlb page check can also be dropped since isolate_migratepages_range is now capable of dealing with those kind of pages.
> b) Similarly, check for gigantic pages and/or movability/migratability.
I lost you here.
isolate_or_dissolve_huge_page() already bails out on hugetlb-gigantic pages.
Or do you mean to place an upfront check here? (hstate_is_gigantic())?
-- Oscar Salvador SUSE L3
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