On Wed, 2018-03-14 at 12:57 -0700, Tejun Heo wrote: > Hello, > > On Sat, Mar 10, 2018 at 04:47:28AM +0100, Mike Galbraith wrote: > > Some form of cpu_exclusive (preferably exactly that, but something else > > could replace it) is needed to define sets that must not overlap any > > other set at creation time or any time thereafter. A set with property > > 'exclusive' is the enabler for fundamentally exclusive (but dynamic!) > > set properties such as 'isolated' (etc etc). > > I'm not sure cpu_exclusive makes sense. A controller knob can either > belong to the parent or the cgroup itself and cpu_exclusive doesn't > make sense in either case. > > 1. cpu_exclusive is owned by the parent as other usual resource > control knobs. IOW, it's not delegatable. > > This is weird because it's asking the kernel to protect against its > own misconfiguration and there's nothing preventing cpu_exclusive > itself being cleared by the same entitya. > > 2. cpu_exclusive is owned by the cgroup itself like memory.oom_group. > IOW, it's delegatable. > > This allows a cgroup to affect what its siblings can or cannot do, > which is broken. Semantically, it doesn't make much sense either. > > I don't think it's a good idea to add a kernel mechanism to prevent > misconfiguration from a single entity. Under the hood v2 details are entirely up to you. My input ends at please don't leave dynamic partitioning standing at the dock when v2 sails. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
