On Fri, May 28, 2010 at 11:06:23PM +0900, Minchan Kim wrote: | On Fri, May 28, 2010 at 09:53:05AM -0300, Luis Claudio R. Goncalves wrote: | > On Fri, May 28, 2010 at 02:59:02PM +0900, KOSAKI Motohiro wrote: ... | > | As far as my observation, RT-function always have some syscall. because pure | > | calculation doesn't need deterministic guarantee. But _if_ you are really | > | using such priority design. I'm ok maximum NonRT priority instead maximum | > | RT priority too. | > | > I confess I failed to distinguish memcg OOM and system OOM and used "in | > case of OOM kill the selected task the faster you can" as the guideline. | > If the exit code path is short that shouldn't be a problem. | > | > Maybe the right way to go would be giving the dying task the biggest | > priority inside that memcg to be sure that it will be the next process from | > that memcg to be scheduled. Would that be reasonable? | | Hmm. I can't understand your point. | What do you mean failing distinguish memcg and system OOM? | | We already have been distinguish it by mem_cgroup_out_of_memory. | (but we have to enable CONFIG_CGROUP_MEM_RES_CTLR). | So task selected in select_bad_process is one out of memcg's tasks when | memcg have a memory pressure. The approach of giving the highest priority to the dying task makes sense in a system wide OOM situation. I though that would also be good for the memcg OOM case. After Balbir Singh's comment, I understand that in a memcg OOM the dying task should have a priority just above the priority of the main task of that memcg, in order to avoid interfering in the rest of the system. That is the point where I failed to distinguish between memcg and system OOM. Should I pursue that new idea of looking for the right priority inside the memcg or is it overkill? I really don't have a clear view of the impact of a memcg OOM on system performance - don't know if it is better to solve the issue sooner (highest RT priority) or leave it to be solved later (highest prio on the memcg). I have the impression the general case points to the simpler solution. Luis -- [ Luis Claudio R. Goncalves Bass - Gospel - RT ] [ Fingerprint: 4FDD B8C4 3C59 34BD 8BE9 2696 7203 D980 A448 C8F8 ] -- 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>