On Thu, 26 May 2011 12:52:07 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 6 May 2011 15:13:02 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > > It would be much better to work out the optimum time at which to rotate > > > the index via some deterministic means. > > > > > > If we can't think of a way of doing that then we should at least pace > > > the rotation frequency via something saner than wall-time. Such as > > > number-of-pages-scanned. > > > > > > > > > What I think now is using reclaim_stat or usigng some fairness based on > > the ratio of inactive file caches. We can calculate the total sum of > > recalaim_stat which gives us a scan_ratio for a whole memcg. And we can > > calculate LRU rotate/scan ratio per node. If rotate/scan ratio is small, > > it will be a good candidate of reclaim target. Hmm, > > > > - check which memory(anon or file) should be scanned. > > (If file is too small, rotate/scan ratio of file is meaningless.) > > - check rotate/scan ratio of each nodes. > > - calculate weights for each nodes (by some logic ?) > > - give a fair scan w.r.t node's weight. > > > > Hmm, I'll have a study on this. > > How's the study coming along ;) > > I'll send this in to Linus today, but I'll feel grumpy while doing so. > We really should do something smarter here - the magic constant will > basically always be suboptimal for everyone and we end up tweaking its > value (if we don't, then the feature just wasn't valuable in the first > place) and then we add a tunable and then people try to tweak the > default setting of the tunable and then I deride them for not setting > the tunable in initscripts and then we have to maintain the stupid > tunable after we've changed the internal implementation and it's all > basically screwed up. > > How to we automatically determine the optimum time at which to rotate, > at runtime? > Ah, I think I should check it after dirty page accounting comes...because ratio of dirty pages is an important information.. Ok, what I think now is just comparing the number of INACTIVE_FILE or the number of FILE CACHES per node. I think we can periodically update per-node and total amount of file caches and we can record per-node node-file-cache * 100/ total-file cache information into memcg's per-node structure. Then, I think we can do some scheduling like lottery scheduling, a scan proportional to the ratio of file caches in the memcg. If it's better to check INACTIVE_ANON, I think swappiness can be used in above calcuration. But yes, I or someone may be able to think of something much better. 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>