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

On Wed, Mar 30, 2016 at 04:11:41PM -0700, Andrew Morton wrote:

On Wed, 30 Mar 2016 16:11:59 +0900 Minchan Kim [off-list ref] wrote:

quoted

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.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>