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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2013-06-26 01:15:36 +0400 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-06-26 03:11:05 +0400 |
| commit | 3766a1abc53164f058d74f950599c797cb3fe302 (patch) | |
| tree | e68b37bda9d162a3806f2a4905782af658706d9c /include/linux/huge_mm.h | |
| parent | 5459ae1431f5d22ab10fa8b56fb16c018289fdfc (diff) | |
| download | linux-3766a1abc53164f058d74f950599c797cb3fe302.tar.xz | |
mm/thp: define HPAGE_PMD_* constants as BUILD_BUG() if !THP
Currently, HPAGE_PMD_* constans rely on PMD_SHIFT regardless of
CONFIG_TRANSPARENT_HUGEPAGE. PMD_SHIFT is not defined everywhere (e.g.
arm nommu case).
It means we can't use anything like this in generic code:
if (PageTransHuge(page))
zero_huge_user(page, 0, HPAGE_PMD_SIZE);
else
clear_highpage(page);
For !THP case, PageTransHuge() is 0 and compiler can eliminate
zero_huge_user() call. But it still need to be valid C expression, means
HPAGE_PMD_SIZE has to expand to something compiler can understand.
Previously, HPAGE_PMD_* were defined to BUILD_BUG() for !THP. Let's come
back to it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'include/linux/huge_mm.h')
| -rw-r--r-- | include/linux/huge_mm.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index cc276d2c3a40..e2dbefb38e3b 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -58,11 +58,12 @@ extern pmd_t *page_check_address_pmd(struct page *page, #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT) #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER) + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE #define HPAGE_PMD_SHIFT PMD_SHIFT #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT) #define HPAGE_PMD_MASK (~(HPAGE_PMD_SIZE - 1)) -#ifdef CONFIG_TRANSPARENT_HUGEPAGE extern bool is_vma_temporary_stack(struct vm_area_struct *vma); #define transparent_hugepage_enabled(__vma) \ @@ -180,6 +181,9 @@ extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vm unsigned long addr, pmd_t pmd, pmd_t *pmdp); #else /* CONFIG_TRANSPARENT_HUGEPAGE */ +#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) +#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; }) +#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; }) #define hpage_nr_pages(x) 1 |