Re: [RFC PATCHv2 2/2] Change khugepaged to respect MMF_THP_DISABLEflag

[Oleg Nesterov]

On 01/16, Alex Thorlton wrote:
>
>  static inline int khugepaged_test_exit(struct mm_struct *mm)
>  {
> -	return atomic_read(&mm->mm_users) == 0;
> +	return atomic_read(&mm->mm_users) == 0 ||
> +	       (mm->flags & MMF_THP_DISABLE_MASK);
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test_bit(MMF_THP_DISABLE) ?

And I am not sure this and another check in transparent_hugepage_enabled
is actually right...

I think that MMF_THP_DISABLE_MASK should not disable thp if this
vma has VM_HUGEPAGE set, iow perhaps madvise() should work even
after PR_SET_THP_DISABLE?

IOW, MMF_THP_DISABLE should act as khugepaged_req_madv().

But again, I won't argue.

Oleg.

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