[Let's CC Ben here - the email thread has started here: http://marc.info/?l=linux-mm&m=143203206402073&w=2 and it seems Debian is disabling memcg controller already so this might be of your interest] On Tue 19-05-15 15:43:45, Mel Gorman wrote: [...] > After I wrote the patch, I spotted that Debian apparently already > does something like this and by coincidence they matched the > parameter name and values. See the memory controller instructions on > https://wiki.debian.org/LXC#Prepare_the_host . So in this case at least > upstream would match something that at least one distro in the field > already uses. I've read through https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534964 and it seems that the primary motivation for the runtime disabling was the _memory_ overhead of the struct page_cgroup (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534964#152). This is no longer the case since 1306a85aed3e ("mm: embed the memcg pointer directly into struct page") merged in 3.19. I can see some point in disabling the memcg due to runtime overhead. There will always be some, albeit hard to notice. If an user really need this to happen there is a command line option for that. The question is who would do CONFIG_MEMCG && !MEMCG_DEFAULT_ENABLED. Do you expect any distributions go that way? Ben, would you welcome such a change upstream or is there a reason to change the Debian kernel runtime default now that the memory overhead is mostly gone (for 3.19+ kernels of course)? -- Michal Hocko SUSE Labs -- 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>