On Tue 18-04-17 14:32:56, David Rientjes wrote: [...] > If the suggestion is checking > NR_ACTIVE_ANON + NR_INACTIVE_ANON > total_high_wmark pages, it would be a > separate heurstic to address a problem that I'm not having :) My issue is > specifically when NR_ACTIVE_FILE + NR_INACTIVE_FILE < total_high_wmark, > NR_ACTIVE_ANON + NR_INACTIVE_ANON is very large, but all not on this > lruvec's evictable lrus. Hmm, why are those pages not moved to the unevictable LRU lists? > This is the reason why I chose lruvec_lru_size() rather than per-node > statistics. The argument could also be made for the file lrus in the > get_scan_count() heuristic that forces SCAN_ANON, but I have not met such > an issue (yet). I could follow-up with that change or incorporate it into > a v2 of this patch if you'd prefer. > > In other words, I want get_scan_count() to not force SCAN_ANON and > fallback to SCAN_FRACT, absent other heuristics, if the amount of > evictable anon is below a certain threshold for this lruvec. I > arbitrarily chose SWAP_CLUSTER_MAX to be conservative, but I could easily > compare to total_high_wmark as well, although I would consider that more > aggressive. > > So we're in global reclaim, our file lrus are below thresholds, but we > don't want to force SCAN_ANON for all lruvecs if there's not enough to > reclaim from evictable anon. Do you have a suggestion for how to > implement this logic other than this patch? I agree that forcing SCAN_ANON without looking at the ANON lru size is not optimal but I would rather see the same criterion for both anon and file. get_scan_count is full of magic heuristics which tend to break for different workloads. Let's not add another magic on top please. -- 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>
