kexec: export free_huge_page to VMCOREINFO
authorAtsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Wed, 30 Jul 2014 23:08:39 +0000 (16:08 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 31 Jul 2014 00:16:13 +0000 (17:16 -0700)
commit8f1d26d0e59b9676587c54578f976709b625d6e9
tree958c513631bd5419175d7a156268e0425b07cdcc
parent75325189c9e4df5f67eec5ec5b0d90759084887b
kexec: export free_huge_page to VMCOREINFO

PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.

If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.

We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():

    int PageHuge(struct page *page)
    {
            if (!PageCompound(page))
                    return 0;

            page = compound_head(page);
            return get_compound_page_dtor(page) == free_huge_page;
    }

For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.

Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/hugetlb.h
kernel/kexec.c
mm/hugetlb.c