mm/hugetlb: introduce minimum hugepage order

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Currently the initial value of order in dissolve_free_huge_page is 64 or
32, which leads to the following warning in static checker:

  mm/hugetlb.c:1203 dissolve_free_huge_pages()
  warn: potential right shift more than type allows '9,18,64'

This is a potential risk of infinite loop, because 1 << order (== 0) is used
in for-loop like this:

  for (pfn =3D start_pfn; pfn < end_pfn; pfn +=3D 1 << order)
      ...

So this patch fixes it by using global minimum_order calculated at boot time.

    text    data     bss     dec     hex filename
   28313     469   84236  113018   1b97a mm/hugetlb.o
   28256     473   84236  112965   1b945 mm/hugetlb.o (patched)

Fixes: c8721bbbdd ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

...

This commit is contained in:

Naoya Horiguchi 2015-06-24 16:56:59 -07:00 • committed by Linus Torvalds

parent 414e2fb8ce

commit 641844f561

1 changed files with 11 additions and 8 deletions

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mm/hugetlb.c

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