On Mon, Jan 06, 2014 at 03:02:56PM +0100, Mike Galbraith wrote: >On Mon, 2014-01-06 at 13:17 +0100, Peter Zijlstra wrote: >> On Fri, Dec 27, 2013 at 06:22:31PM +0800, Wanpeng Li wrote: >> > We have a server which have 200 CPUs and 8G memory, there is auto_group creation >> >> I'm hoping that is 8T, otherwise that's a severely under provisioned >> system, that's a mere 40M per cpu, does that even work? >> >> > which will almost consume 12MB memory even if add 'noautogroup' in the kernel >> > boot parameter. In addtion, SLUB per cpu partial caches freeing that is local to >> > a processor which requires the taking of locks at the price of more indeterminism >> > in the latency of the free. This patch fix it by check noautogroup earlier to avoid >> > free after unnecessary memory consumption. >> >> That's just a bad changelog. It fails to explain the actual problem and >> it babbles about unrelated things like SLUB details. >> >> Also, I'm not entirely sure what the intention was of this code, I've so >> far tried to ignore the entire autogroup fest... >> >> It looks like it creates and maintains the entire autogroup hierarchy, >> such that if you at runtime enable the sysclt and move tasks 'back' to >> the root cgroup you get the autogroup behaviour. >> >> Was this intended? Mike? > >Yeah, it was intended that autogroups always exist if you config it in. >We could make is such that noautogroup makes it irreversibly off/dead. > >People with 200 ram starved CPUs can turn it off in their .config too :) Thanks for your great explaination. Regards, Wanpeng Li > >-Mike > >-- >To unsubscribe, send a message with 'unsubscribe linux-mm' in >the body to majordomo@xxxxxxxxx. For more info on Linux MM, >see: http://www.linux-mm.org/ . >Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>