Re: [RFC PATCH] mm: dump_page: print total mapcount for compound page

From: Kirill A. Shutemov
Date: Mon May 31 2021 - 04:19:04 EST


On Fri, May 28, 2021 at 12:47:31PM -0700, Hugh Dickins wrote:
> > page if possible. But how to implement it safely seems controversial.
> > Some ideas and potential problems have been discussed by
> > https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2105261733110.16920@eggly.anvils/.
> >
> > So I prepared this patch to show a possible approach to get some
> > feedback. The same thing could be decoded by the reader of page dump
> > as well by using the same formula used by this patch. However it sounds
> > more convenient to have kernel do the math.
> >
> > mm/debug.c | 35 +++++++++++++++++++++++++++++------
> > 1 file changed, 29 insertions(+), 6 deletions(-)
>
> Adding that code to come up with a deceptive approximation to a number
> which most sites won't care about: speaking for me, I'll say no.

I agree. The approximation may bring more confusion than help debugging.

--
Kirill A. Shutemov