Re: [PATCH v9 2/8] mm: Adjust shuffle code to allow for future coalescing

Alexander Duyck
2019-09-09T16:43:03Z

On Mon, 2019-09-09 at 12:47 +0300, Kirill A. Shutemov wrote:
> On Sat, Sep 07, 2019 at 10:25:20AM -0700, Alexander Duyck wrote:
> > From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> >
> > Move the head/tail adding logic out of the shuffle code and into the
> > __free_one_page function since ultimately that is where it is really
> > needed anyway. By doing this we should be able to reduce the overhead
> > and can consolidate all of the list addition bits in one spot.
> >
> > Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> > ---
> > include/linux/mmzone.h | 12 --------
> > mm/page_alloc.c | 70 +++++++++++++++++++++++++++---------------------
> > mm/shuffle.c | 9 +-----
> > mm/shuffle.h | 12 ++++++++
> > 4 files changed, 53 insertions(+), 50 deletions(-)
> >
> > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> > index bda20282746b..125f300981c6 100644
> > --- a/include/linux/mmzone.h
> > +++ b/include/linux/mmzone.h
> > @@ -116,18 +116,6 @@ static inline void add_to_free_area_tail(struct page *page, struct free_area *ar
> > area->nr_free++;
> > }
> >
> > -#ifdef CONFIG_SHUFFLE_PAGE_ALLOCATOR
> > -/* Used to preserve page allocation order entropy */
> > -void add_to_free_area_random(struct page *page, struct free_area *area,
> > - int migratetype);
> > -#else
> > -static inline void add_to_free_area_random(struct page *page,
> > - struct free_area *area, int migratetype)
> > -{
> > - add_to_free_area(page, area, migratetype);
> > -}
> > -#endif
> > -
> > /* Used for pages which are on another list */
> > static inline void move_to_free_area(struct page *page, struct free_area *area,
> > int migratetype)
>
> Looks like add_to_free_area() and add_to_free_area_tail() can be moved to
> mm/page_alloc.c as all users are there now. And the same for struct
> free_area definition (but not declaration).

This can probably be worked into patch 4 instead of doing it here. I could
pull all the functions that are renamed to _free_list from _free_area into
page_alloc.c and leave behind the ones that remained as _free_area such as
get_page_from_free_area. That should make it easier for me to avoid having
to include page_reporting.h in mmzone.h.

I'm not sure I follow what you are saying about the free_area definition.
It looks like it is a part of the zone structure so I would think it still
needs to be defined in the header.