Messages in this thread | | | Subject | Re: [PATCH v7 06/15] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two | From | David Hildenbrand <> | Date | Wed, 9 Dec 2020 10:57:33 +0100 |
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On 30.11.20 16:18, Muchun Song wrote: > We only can free the tail vmemmap pages of HugeTLB to the buddy allocator > when the size of struct page is a power of two. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > mm/hugetlb_vmemmap.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > index 51152e258f39..ad8fc61ea273 100644 > --- a/mm/hugetlb_vmemmap.c > +++ b/mm/hugetlb_vmemmap.c > @@ -111,6 +111,11 @@ void __init hugetlb_vmemmap_init(struct hstate *h) > unsigned int nr_pages = pages_per_huge_page(h); > unsigned int vmemmap_pages; > > + if (!is_power_of_2(sizeof(struct page))) { > + pr_info("disable freeing vmemmap pages for %s\n", h->name);
I'd just drop that pr_info(). Users are able to observe that it's working (below), so they are able to identify that it's not working as well.
> + return; > + } > + > vmemmap_pages = (nr_pages * sizeof(struct page)) >> PAGE_SHIFT; > /* > * The head page and the first tail page are not to be freed to buddy >
Please squash this patch into the enabling patch and add a comment instead, like
/* We cannot optimize if a "struct page" crosses page boundaries. */
-- Thanks,
David / dhildenb
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