On Tue, 8 Mar 2011 08:45:51 +0900 Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > On Tue, Mar 8, 2011 at 6:58 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Sun, 6 Mar 2011 02:07:59 +0900 > > Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > > Any alternative proposals? ÂWe should get the livelock fixed if possible.. > > > > And we should avoid unnecessary OOM kill if possible. > > I think the problem is caused by (zone->pages_scanned < > zone_reclaimable_pages(zone) * 6). I am not sure (* 6) is a best. It > would be rather big on recent big DRAM machines. > It means 3 times full-scan from the highest priority to the lowest and cannot freed any pages. I think big memory machine tend to have more cpus, so don't think it's big. > I think it is a trade-off between latency and OOM kill. > If we decrease the magic value, maybe we should prevent the almost > livelock but happens unnecessary OOM kill. > Hmm, should I support a sacrifice feature 'some signal(SIGINT?) will be sent by the kernel when it detects system memory is in short' in cgroup ? (For example, if full LRU scan is done in a zone, notifier works and SIGINT will be sent.) > And I think zone_reclaimable not fair. > For example, too many scanning makes reclaimable state to > unreclaimable state. Maybe it takes a very long time. But just some > page free makes unreclaimable state to reclaimabe with very easy. So > we need much painful reclaiming for changing reclaimable state with > unreclaimabe state. it would affect latency very much. > > Maybe we need more smart zone_reclaimabe which is adaptive with memory pressure. > I agree. Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>