On Mon, May 30, 2022 at 02:40:49AM +0200, Frederic Weisbecker wrote: > On Sat, May 28, 2022 at 04:24:50PM +0200, Peter Zijlstra wrote: > > On Fri, May 27, 2022 at 10:30:18AM +0200, Juri Lelli wrote: > > > Hi, > > > > > > On 26/05/22 14:37, Tejun Heo wrote: > > > > On Thu, May 26, 2022 at 08:28:43PM -0400, Waiman Long wrote: > > > > > I am thinking along the line that it will not be hierarchical. However, > > > > > cpuset can be useful if we want to have multiple isolated partitions > > > > > underneath the top cpuset with different isolation attributes, but no more > > > > > sub-isolated partition with sub-attributes underneath them. IOW, we can only > > > > > set them at the first level under top_cpuset. Will that be useful? > > > > > > > > At that point, I'd just prefer to have it under /proc or /sys. > > > > > > FWIW, I was under the impression that this would nicely fit along the > > > side of other feaures towards implenting dynamic isolation of CPUs (say > > > https://lore.kernel.org/lkml/20220510153413.400020-1-longman@xxxxxxxxxx/ > > > for example). Wouldn't be awkward to have to poke different places to > > > achieve isolation at runtime? > > > > This, that's what I was thinking. > > > > My main objection to the whole thing is that it's an RCU_NOCB specific > > interface. *That* I think is daft. > > > > I was thinking a partition would be able to designate a house-keeping > > sub-partition/mask, but who cares about all the various different > > housekeeping parties. > > It's time for the isolation users to step up here! I very rarely hear from them > and I just can't figure out by myself all the variants of uses for each of the > isolation features. May be some people are only interested in nocb for some > specific uses, or may be it never makes sense without nohz full and all the rest > of the isolation features. So for now I take the very cautious path to split the > interface. This is ABI, you can't walk back on it. I would suggest starting with an 'all feature' isolation. Only if there's real demand for something more fine-grained add that on top. Simple first etc.
