Re: [RFC] mm: show message when updating min_free_kbytes in thp

Michal Hocko
2014-01-08T10:16:18Z

On Wed 08-01-14 16:20:01, Han Pingtian wrote:
> On Mon, Jan 06, 2014 at 05:46:04PM +0100, Michal Hocko wrote:
> > On Sun 05-01-14 08:35:01, Han Pingtian wrote:
> > [...]
> > > From f4d085a880dfae7638b33c242554efb0afc0852b Mon Sep 17 00:00:00 2001
> > > From: Han Pingtian <hanpt@linux.vnet.ibm.com>
> > > Date: Fri, 3 Jan 2014 11:10:49 +0800
> > > Subject: [PATCH] mm: show message when raising min_free_kbytes in THP
> > >
> > > min_free_kbytes may be raised during THP's initialization. Sometimes,
> > > this will change the value being set by user. Showing message will
> > > clarify this confusion.
> >
> > I do not have anything against informing about changing value
> > set by user but this will inform also when the default value is
> > updated. Is this what you want? Don't you want to check against
> > user_min_free_kbytes? (0 if not set by user)
> >
>
> To use user_min_free_kbytes in mm/huge_memory.c, we need a
>
> extern int user_min_free_kbytes;

The variable is not defined as static so you can use it outside of
mm/page_alloc.c.

> in somewhere? Where should we put it? I guess it is mm/internal.h,
> right?

I do not think this has to be globaly visible though. Why not just
extern declaration in mm/huge_memory.c?

--
Michal Hocko
SUSE Labs