Messages in this thread | | | Date | Wed, 3 Feb 2016 00:50:58 +0200 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH] mm/hugetlb: fix gigantic page initialization/allocation |
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On Tue, Feb 02, 2016 at 02:33:40PM -0800, Mike Kravetz wrote: > Attempting to preallocate 1G gigantic huge pages at boot time with > "hugepagesz=1G hugepages=1" on the kernel command line will prevent > booting with the following: > > kernel BUG at mm/hugetlb.c:1218! > > When mapcount accounting was reworked, the setting of compound_mapcount_ptr > in prep_compound_gigantic_page was overlooked. As a result, the validation > of mapcount in free_huge_page fails.
Oops. Soory for that.
> > The "BUG_ON" checks in free_huge_page were also changed to "VM_BUG_ON_PAGE" > to assist with debugging. > > Fixes: af5642a8af ("mm: rework mapcount accounting to enable 4k mapping of THPs") > Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> --- > mm/hugetlb.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 12908dc..d7a8024 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1214,8 +1214,8 @@ void free_huge_page(struct page *page) > > set_page_private(page, 0); > page->mapping = NULL; > - BUG_ON(page_count(page)); > - BUG_ON(page_mapcount(page)); > + VM_BUG_ON_PAGE(page_count(page), page); > + VM_BUG_ON_PAGE(page_mapcount(page), page); > restore_reserve = PagePrivate(page); > ClearPagePrivate(page); > > @@ -1286,6 +1286,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order) > set_page_count(p, 0); > set_compound_head(p, page); > } > + atomic_set(compound_mapcount_ptr(page), -1); > } > > /* > -- > 2.4.3 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
-- Kirill A. Shutemov
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