Hi Minchan,
On (11/05/15 08:39), Minchan Kim wrote:
[..]
> >
> > I think it makes sense to update pmd_trans_unstable() and
> > pmd_none_or_trans_huge_or_clear_bad() comments in asm-generic/pgtable.h
> > Because they explicitly mention MADV_DONTNEED only. Just a thought.
>
> Hmm, When I read comments(but actually I don't understand it 100%), it
> says pmd disappearing from MADV_DONTNEED with mmap_sem read-side
> lock. But MADV_FREE doesn't remove the pmd. So, I don't understand
> what I should add comment. Please suggest if I am missing something.
>
Hm, sorry, I need to think about it more, probably my comment is irrelevant.
Was fantasizing some stupid use cases like doing MADV_DONTNEED and MADV_FREE
on overlapping addresses from different threads, processes that share mem, etc.
> > > @@ -379,6 +502,14 @@ madvise_vma(struct vm_area_struct *vma, struct
> > > vm_area_struct **prev,
> > > return madvise_remove(vma, prev, start, end);
> > > case MADV_WILLNEED:
> > > return madvise_willneed(vma, prev, start, end);
> > > + case MADV_FREE:
> > > + /*
> > > + * XXX: In this implementation, MADV_FREE works like
> > ^^^^
> > XXX
>
> What does it mean?
not much. just a minor note that there is a 'XXX' in "XXX: In this
implementation"
comment.
-ss
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