diff options
| author | Mel Gorman <mgorman@suse.de> | 2015-02-12 14:58:35 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 18:54:08 -0800 |
| commit | e944fd67b625c02bda4a78ddf85e413c5e401474 (patch) | |
| tree | 73430e339d1d27b315b3789bc0a271882ecf9174 /mm/mprotect.c | |
| parent | 21d9ee3eda7792c45880b2f11bff8e95c9a061fb (diff) | |
mm: numa: do not trap faults on the huge zero page
Faults on the huge zero page are pointless and there is a BUG_ON to catch
them during fault time. This patch reintroduces a check that avoids
marking the zero page PAGE_NONE.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mprotect.c')
| -rw-r--r-- | mm/mprotect.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index 76824d73380d..dd599fc235c2 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -76,6 +76,18 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (pte_present(oldpte)) { pte_t ptent; + /* + * Avoid trapping faults against the zero or KSM + * pages. See similar comment in change_huge_pmd. + */ + if (prot_numa) { + struct page *page; + + page = vm_normal_page(vma, addr, oldpte); + if (!page || PageKsm(page)) + continue; + } + ptent = ptep_modify_prot_start(mm, addr, pte); ptent = pte_modify(ptent, newprot); @@ -142,7 +154,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, split_huge_page_pmd(vma, addr, pmd); else { int nr_ptes = change_huge_pmd(vma, pmd, addr, - newprot); + newprot, prot_numa); if (nr_ptes) { if (nr_ptes == HPAGE_PMD_NR) { |