On Fri, Feb 10, 2017 at 02:02:36PM +0100, Michal Hocko wrote: > On Fri 03-02-17 15:33:18, Shaohua Li wrote: > > Userspace indicates MADV_FREE pages could be freed without pageout, so > > it pretty much likes used once file pages. For such pages, we'd like to > > reclaim them once there is memory pressure. Also it might be unfair > > reclaiming MADV_FREE pages always before used once file pages and we > > definitively want to reclaim the pages before other anonymous and file > > pages. > > > > To speed up MADV_FREE pages reclaim, we put the pages into > > LRU_INACTIVE_FILE list. The rationale is LRU_INACTIVE_FILE list is tiny > > nowadays and should be full of used once file pages. Reclaiming > > MADV_FREE pages will not have much interfere of anonymous and active > > file pages. And the inactive file pages and MADV_FREE pages will be > > reclaimed according to their age, so we don't reclaim too many MADV_FREE > > pages too. Putting the MADV_FREE pages into LRU_INACTIVE_FILE_LIST also > > means we can reclaim the pages without swap support. This idea is > > suggested by Johannes. > > > > We also clear the pages SwapBacked flag to indicate they are MADV_FREE > > pages. > > I like this. I have expected this to be more convoluted but it looks > quite straightforward. I didn't get to do a really deep review and add > my acked-by but from a quick look there do not seem to be any surprises. > I was worried about vmstat accounting. There are some places which > isolate page from LRU and account based on the LRU and later use > page_is_file_cache to tell which LRU this was. This should work fine, > though, because you never touch pages which are off-lru. > > That being said I do not see any major issues. There might be some minor > things and this will need a lot of testing but it is definitely a move > into right direction. I hope to do the deeper review after I get back > from vacation (20th Feb). Sweat! Thanks for your time! > > Cc: Michal Hocko <mhocko@xxxxxxxx> > > Cc: Minchan Kim <minchan@xxxxxxxxxx> > > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > > Cc: Rik van Riel <riel@xxxxxxxxxx> > > Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > I guess > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > would be appropriate. Sure, will add in next post and will add 'the patches are based on Minchan's patches' too. Thanks, Shaohua -- 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>
