On Fri, 2019-11-15 at 11:17 -0500, Johannes Weiner wrote: > On Fri, Nov 15, 2019 at 09:04:57AM -0500, Qian Cai wrote: > > The -next commit "mm: vmscan: enforce inactive:active ratio at the > > reclaim root" [1] introduced some GCC -Wenum-conversion warnings, > > > > mm/vmscan.c:2216:39: warning: implicit conversion from enumeration type > > 'enum lru_list' to different enumeration type 'enum node_stat_item' > > [-Wenum-conversion] > > inactive = lruvec_page_state(lruvec, inactive_lru); > > ~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~ > > mm/vmscan.c:2217:37: warning: implicit conversion from enumeration type > > 'enum lru_list' to different enumeration type 'enum node_stat_item' > > [-Wenum-conversion] > > active = lruvec_page_state(lruvec, active_lru); > > ~~~~~~~~~~~~~~~~~ ^~~~~~~~~~ > > mm/vmscan.c:2746:42: warning: implicit conversion from enumeration type > > 'enum lru_list' to different enumeration type 'enum node_stat_item' > > [-Wenum-conversion] > > file = lruvec_page_state(target_lruvec, LRU_INACTIVE_FILE); > > Interesting, it doesn't show these for me with gcc-9.2.0. Sorry, I meant to say it is clang. > > We should definitely fix these! > > > @@ -2213,8 +2213,9 @@ static bool inactive_is_low(struct lruvec *lruvec, enum lru_list inactive_lru) > > unsigned long inactive_ratio; > > unsigned long gb; > > > > - inactive = lruvec_page_state(lruvec, inactive_lru); > > - active = lruvec_page_state(lruvec, active_lru); > > + inactive = lruvec_page_state(lruvec, > > + (enum node_stat_item)inactive_lru); > > + active = lruvec_page_state(lruvec, (enum node_stat_item)active_lru); > > This is fragile, as it relies on the absolute values being identical, > which we don't guarantee. However, we do guarantee the relative order > between the LRU items, and we use NR_LRU_BASE for the translation. > > Please use NR_LRU_BASE + (in)active_lru here. > > > @@ -2743,7 +2744,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) > > * thrashing, try to reclaim those first before touching > > * anonymous pages. > > */ > > - file = lruvec_page_state(target_lruvec, LRU_INACTIVE_FILE); > > + file = lruvec_page_state(target_lruvec, > > + (enum node_stat_item)LRU_INACTIVE_FILE); > > This should just directly use NR_INACTIVE_FILE instead. > > Thanks
