On Mon 22-04-13 08:46:20, Tejun Heo wrote: > Hey, Michal. > > On Mon, Apr 22, 2013 at 05:37:30PM +0200, Michal Hocko wrote: > > > In fact, I'm planning to disallow changing ownership of cgroup files > > > when "sane_behavior" is specified. > > > > I would be wildly oposing this. Enabling user to play on its own ground > > while above levels of the groups enforce the reasonable behavior is very > > important use case. > > We can continue this discussion on the original thread and I'm not too > firm on this not because it's a sane use case but because it is an > extra measure preventing root from shooting its feet which we > traditionally allow. That said, really, no good can come from > delegating hierarchy to different security domains. It's already > discouraged by the userland best practices doc. Just don't do it. OK, I will go to the original mail thread and discuss my concerns there. > > Tejun, stop this, finally! Current soft limit same as the reworked > > version follow the basic nesting rule we use for the hard limit which > > says that parent setting is always more strict than its children. > > So if you parent says you are hitting the hardlimit (resp. over soft > > limit) then children are reclaimed regardless their hard/soft limit > > setting. > > Okay, thanks for making it clear. Then, apparently, the fine folks at > google are hopelessly confused because at least Greg and Ying told me > something which is the completely opposite of what you're saying. You > guys need to sort it out. > > > It is you being confused and refuse to open the damn documentation and > > read what the hack is soft limit and what it is used for. Read the patch > > series I was talking about and you will hardly find anything regarding > > _guarantee_. > > Oh, if so, I'm happy. Sorry about being brash on the thread; however, > please talk with google memcg people. They have very different > interpretation of what "softlimit" is and are using it according to > that interpretation. If it *is* an actual soft limit, there is no > inherent isolation coming from it and that should be clear to > everyone. We have discussed that for a long time. I will not speak for Greg & Ying but from my POV we have agreed that the current implementation will work for them with some (minor) changes in their layout. As I have said already with a careful configuration (e.i. setting the soft limit only where it matters - where it protects an important memory which is usually in the leaf nodes) you can actually achieve _high_ probability for not being reclaimed after the rework which was not possible before because of the implementation which was ugly and smelled. > > Thanks. > > -- > tejun -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
