Messages in this thread | | | Subject | Re: [PATCH] mm/page_alloc: Ensure that HUGETLB_PAGE_ORDER is less than MAX_ORDER | From | David Hildenbrand <> | Date | Fri, 9 Apr 2021 10:24:18 +0200 |
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On 09.04.21 07:55, Anshuman Khandual wrote: > pageblock_order must always be less than MAX_ORDER, otherwise it might lead > to an warning during boot. A similar problem got fixed on arm64 platform > with the commit 79cc2ed5a716 ("arm64/mm: Drop THP conditionality from > FORCE_MAX_ZONEORDER"). Assert the above condition before HUGETLB_PAGE_ORDER > gets assigned as pageblock_order. This will help detect the problem earlier > on platforms where HUGETLB_PAGE_SIZE_VARIABLE is enabled. > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > mm/page_alloc.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 604dcd69397b..81b7460e1228 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7068,10 +7068,17 @@ void __init set_pageblock_order(void) > if (pageblock_order) > return; > > - if (HPAGE_SHIFT > PAGE_SHIFT) > + if (HPAGE_SHIFT > PAGE_SHIFT) { > + /* > + * pageblock_order must always be less than > + * MAX_ORDER. So does HUGETLB_PAGE_ORDER if > + * that is being assigned here. > + */ > + WARN_ON(HUGETLB_PAGE_ORDER >= MAX_ORDER);
Can't that be a BUILD_BUG_ON() ?
> order = HUGETLB_PAGE_ORDER; > - else > + } else { > order = MAX_ORDER - 1; > + } > > /* > * Assume the largest contiguous order of interest is a huge page. >
-- Thanks,
David / dhildenb
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