Re: [PATCH 1/6] mm/compaction: split freepages without holding the zone lock

[Joonsoo Kim]

On Tue, May 10, 2016 at 04:56:45PM +0200, Vlastimil Babka wrote:
> On 05/03/2016 07:22 AM, js1304@xxxxxxxxx wrote:
> > From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> > 
> > We don't need to split freepages with holding the zone lock. It will cause
> > more contention on zone lock so not desirable.
> 
> Fair enough, I just worry about the same thing as Hugh pointed out
> recently [1] in that it increases the amount of tricky stuff in
> compaction.c doing similar but not quite the same stuff as page/alloc.c,
> and which will be forgotten to be updated once somebody updates
> prep_new_page with e.g. a new debugging check. Can you perhaps think of
> a more robust solution here?

I will try it. I think that factoring some part of prep_new_page() out
would be enough to make thing robust.

Thanks.