On Wed, May 19, 2010 at 5:44 PM, KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > Shaohua Li reported parallel file copy on tmpfs can lead to > OOM killer. This is regression of caused by commit 9ff473b9a7 > (vmscan: evict streaming IO first). Wow, It is 2 years old patch! > > Currently, tmpfs file cache is inserted active list at first. It > mean the insertion doesn't only increase numbers of pages in anon LRU, > but also reduce anon scanning ratio. Therefore, vmscan will get totally > confusion. It scan almost only file LRU even though the system have > plenty unused tmpfs pages. > > Historically, lru_cache_add_active_anon() was used by two reasons. > 1) Intend to priotize shmem page rather than regular file cache. > 2) Intend to avoid reclaim priority inversion of used once pages. > > But we've lost both motivation because (1) Now we have separate > anon and file LRU list. then, to insert active list doesn't help > such priotize. (2) In past, one pte access bit will cause page > activation. then to insert inactive list with pte access bit mean > higher priority than to insert active list. Its priority inversion > may lead to uninteded lru chun. but it was already solved by commit > 645747462 (vmscan: detect mapped file pages used only once). > (Thanks Hannes, you are great!) > > Thus, now we can use lru_cache_add_anon() instead. > > Reported-by: Shaohua Li <shaohua.li@xxxxxxxxx> > Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Minchan Kim <minchan.kim@xxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> The description itself is valuable. :) Thanks, Kosaki. -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>