On Fri, 20 May 2011, KOSAKI Motohiro wrote: > CAI Qian reported his kernel did hang-up if he ran fork intensive > workload and then invoke oom-killer. > > The problem is, current oom calculation uses 0-1000 normalized value > (The unit is a permillage of system-ram). Its low precision make > a lot of same oom score. IOW, in his case, all processes have smaller > oom score than 1 and internal calculation round it to 1. > > Thus oom-killer kill ineligible process. This regression is caused by > commit a63d83f427 (oom: badness heuristic rewrite). > > The solution is, the internal calculation just use number of pages > instead of permillage of system-ram. And convert it to permillage > value at displaying time. > > This patch doesn't change any ABI (included /proc/<pid>/oom_score_adj) > even though current logic has a lot of my dislike thing. > Same response as when you initially proposed this patch: http://marc.info/?l=linux-kernel&m=130507086613317 -- you never replied to that. The changelog doesn't accurately represent CAI Qian's problem; the issue is that root processes are given too large of a bonus in comparison to other threads that are using at most 1.9% of available memory. That can be fixed, as I suggested by giving 1% bonus per 10% of memory used so that the process would have to be using 10% before it even receives a bonus. I already suggested an alternative patch to CAI Qian to greatly increase the granularity of the oom score from a range of 0-1000 to 0-10000 to differentiate between tasks within 0.01% of available memory (16MB on CAI Qian's 16GB system). I'll propose this officially in a separate email. This patch also includes undocumented changes such as changing the bonus given to root processes. -- 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>