Re: [PATCH v3 00/16] Support non-lru page migration

Minchan Kim
2016-03-31T00:55:34Z

On Wed, Mar 30, 2016 at 04:11:41PM -0700, Andrew Morton wrote:
> On Wed, 30 Mar 2016 16:11:59 +0900 Minchan Kim <minchan@kernel.org> wrote:
>
> > Recently, I got many reports about perfermance degradation
> > in embedded system(Android mobile phone, webOS TV and so on)
> > and failed to fork easily.
> >
> > The problem was fragmentation caused by zram and GPU driver
> > pages. Their pages cannot be migrated so compaction cannot
> > work well, either so reclaimer ends up shrinking all of working
> > set pages. It made system very slow and even to fail to fork
> > easily.
> >
> > Other pain point is that they cannot work with CMA.
> > Most of CMA memory space could be idle(ie, it could be used
> > for movable pages unless driver is using) but if driver(i.e.,
> > zram) cannot migrate his page, that memory space could be
> > wasted. In our product which has big CMA memory, it reclaims
> > zones too exccessively although there are lots of free space
> > in CMA so system was very slow easily.
> >
> > To solve these problem, this patch try to add facility to
> > migrate non-lru pages via introducing new friend functions
> > of migratepage in address_space_operation and new page flags.
> >
> > (isolate_page, putback_page)
> > (PG_movable, PG_isolated)
> >
> > For details, please read description in
> > "mm/compaction: support non-lru movable page migration".
>
> OK, I grabbed all these.
>
> I wonder about testing coverage during the -next period. How many
> people are likely to exercise these code paths in a serious way before
> it all hits mainline?

I asked this patchset to production team in my company for stress
testing. They alaways catch zram/zsmalloc bugs I have missed so
I hope they help me well, too.

About ballooning part, I hope Rafael Aquini get a time to review
and test it.

Other than that, IOW, linux-next will have a enough time to
test common migration part modification, I guess. :)

Thanks.