Messages in this thread Patch in this message | | | Date | Wed, 26 Feb 2014 11:22:53 -0600 | From | Alex Thorlton <> | Subject | Re: + mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch added to -mm tree |
| |
On Wed, Feb 26, 2014 at 05:57:59PM +0100, Peter Zijlstra wrote: > On Wed, Feb 26, 2014 at 04:31:44PM +0100, Oleg Nesterov wrote: > Do we want a comment here, explaining why s390 is special again?
Here's what I've got, with everybody's suggestions spun together:
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 82166bf..7f01491 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1968,8 +1968,6 @@ out: int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags, int advice) { - struct mm_struct *mm = vma->vm_mm; - switch (advice) { case MADV_HUGEPAGE: /* @@ -1977,8 +1975,16 @@ int hugepage_madvise(struct vm_area_struct *vma, */ if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) return -EINVAL; - if (mm->def_flags & VM_NOHUGEPAGE) + +/* + * MADV_HUGEPAGE after PRCTL_THP_DISABLE is broken on s390 because + * qemu blindly does madvise(MADV_HUGEPAGE) after s390_enable_sie(). + */ +#ifdef CONFIG_S390 + if (mm_has_pgste(vma->vm_mm)) return -EINVAL; +#endif + *vm_flags &= ~VM_NOHUGEPAGE; *vm_flags |= VM_HUGEPAGE; /* I've compiled and tested and it works ok on my machines (I don't have an s390 to test on though :). Is everybody okay with this solution?
BTW, Kirill, I looked at using IS_ENABLED to clean up the ifdef, but it won't work here, since mm_has_pgste isn't defined unless CONFIG_S390 is defined. i.e.: This line:
if (IS_ENABLED(CONFIG_S390) && mm_has_pgste(vma->vm_mm)) won't compile.
| |