Hi Kirill, while looking at the issue reported by Minchan [1] I have noticed that there is nothing to prevent from "isolating" a tail page from LRU because isolate_lru_page checks PageLRU which is PAGEFLAG(LRU, lru, PF_HEAD) so it is checked on the head page rather than the given page directly but the rest of the operation is done on the given (tail) page. This is really subtle because this expects that every caller of this function checks for the tail page otherwise we would clobber statistics and who knows what else (I haven't checked that in detail) as the page cannot be on the LRU list and the operation makes sense only on the head page. Would it make more sense to make PageLRU PF_ANY? That would return false for PageLRU on any tail page and so it would be ignored by isolate_lru_page. I haven't checked other flags but there might be a similar situation. I am wondering whether it is really a good idea to perform a flag check on a different page then the operation which depends on the result of the test in general. It sounds like a maintenance horror to me. [1] http://lkml.kernel.org/r/20151201133455.GB27574@bbox -- Michal Hocko SUSE Labs -- 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>