On Mon 30-10-17 14:36:39, David Rientjes wrote: > On Fri, 27 Oct 2017, Roman Gushchin wrote: > > > The thing is that the hierarchical approach (as in v8), which are you pushing, > > has it's own limitations, which we've discussed in details earlier. There are > > reasons why v12 is different, and we can't really simple go back. I mean if > > there are better ideas how to resolve concerns raised in discussions around v8, > > let me know, but ignoring them is not an option. > > > > I'm not ignoring them, I have stated that we need the ability to protect > important cgroups on the system without oom disabling all attached > processes. If that is implemented as a memory.oom_score_adj with the same > semantics as /proc/pid/oom_score_adj, i.e. a proportion of available > memory (the limit), it can also address the issues pointed out with the > hierarchical approach in v8. No it cannot and it would be a terrible interface to have as well. You do not want to permanently tune oom_score_adj to compensate for structural restrictions on the hierarchy. > If this is not the case, could you elaborate > on what your exact concern is and why we do not care that users can > completely circumvent victim selection by creating child cgroups for other > controllers? > > Since the ability to protect important cgroups on the system may require a > heuristic change, I think it should be solved now rather than constantly > insisting that we can make this patchset complete later and in the > meantime force the user to set all attached processes to be oom disabled. I believe, and Roman has pointed that out as well already, that further improvements can be implemented without changing user visible behavior as and add-on. If you disagree then you better come with a solid proof that all of us wrong and reasonable semantic cannot be achieved that way. -- 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>
