Hello Andrew, On Mon, Mar 21, 2016 at 03:30:49PM +0900, Minchan Kim 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". > > Originally, Gioh Kim tried to support this feature but he moved > so I took over the work. But I took many code from his work and > changed a little bit. > Thanks, Gioh! > > And I should mention Konstantin Khlebnikov. He really heped Gioh > at that time so he should deserve to have many credit, too. > Thanks, Konstantin! > > This patchset consists of five parts > > 1. clean up migration > mm: use put_page to free page instead of putback_lru_page > > 2. zsmalloc clean-up for preparing page migration > zsmalloc: use first_page rather than page > zsmalloc: clean up many BUG_ON > zsmalloc: reordering function parameter > zsmalloc: remove unused pool param in obj_free > zsmalloc: keep max_object in size_class > zsmalloc: squeeze inuse into page->mapping > zsmalloc: squeeze freelist into page->mapping > zsmalloc: move struct zs_meta from mapping to freelist > zsmalloc: factor page chain functionality out > zsmalloc: separate free_zspage from putback_zspage > zsmalloc: zs_compact refactoring In this series, [2-5] are clean up regardless of goal of the patchset so it could be merged independently. I want to reduce patchset size in next post. If anyone are not against, could you merge cleanup patchset? zsmalloc: use first_page rather than page zsmalloc: clean up many BUG_ON zsmalloc: reordering function parameter zsmalloc: remove unused pool param in obj_free Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>