MPOL_MF_LAZY is not visible from userspace since 'commit a720094ded8c ("mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now")' , but it should still skip non-migratable VMAs such as VM_IO, VM_PFNMAP, and VM_HUGETLB VMAs, and avoid useless overhead of minor faults.
Signed-off-by: Liang Chen <liangchen.li...@gmail.com> Signed-off-by: Gavin Guo <gavin....@canonical.com> --- Changes since v2: - Add more description into the changelog We have been evaluating the enablement of MPOL_MF_LAZY again, and found this issue. And we decided to push this patch upstream no matter if we finally determine to propose re-enablement of MPOL_MF_LAZY or not. Since it can be a potential problem even if MPOL_MF_LAZY is not enabled this time. --- mm/mempolicy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 87a1779..436ff411 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -610,7 +610,8 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, if (flags & MPOL_MF_LAZY) { /* Similar to task_numa_work, skip inaccessible VMAs */ - if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) + if (vma_migratable(vma) && + vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) change_prot_numa(vma, start, endvma); return 1; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/