On Thu, Aug 19, 2010 at 05:06:12PM +0100, Mel Gorman wrote: > On Fri, Aug 20, 2010 at 12:46:38AM +0900, Minchan Kim wrote: > Mel. Could you consider normal(or small) system but has two core at least? > > I did consider it but I was not keen on the idea of small systems behaving > very differently to large systems in this regard. I thought there was a > danger that a problem problem would be hidden by such a move. > > > I means we apply you rule according to the number of CPU and RAM size. (ie, > > threshold value). > > Now mobile system begin to have two core in system and above 1G RAM. > > Such case, it has threshold 8. > > > > It is unlikey to happen livelock. > > Is it worth to have such overhead in such system? > > What do you think? > > > > Such overhead could be avoided if we made a check like the following in > refresh_zone_stat_thresholds() > > /* > * Only set percpu_drift_mark if there is a danger that > * NR_FREE_PAGES reports the low watermark is ok when in fact > * the min watermark could be breached by an allocation > */ > tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone); > max_drift = num_online_cpus() * threshold; > if (max_drift > tolerate_drift) > zone->percpu_drift_mark = high_wmark_pages(zone) > + max_drift; > > Would this be preferable? Yes. It looks good to me. > > -- > Mel Gorman > Part-time Phd Student Linux Technology Center > University of Limerick IBM Dublin Software Lab -- Kind regards, Minchan Kim -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>