Hello, On Thu, Jul 28, 2022 at 02:57:28PM -0400, Waiman Long wrote: > There can be a counter argument that if a user found out that there is not > enough cpus in a cpuset to meet its performance target, one can always > increase the number of cpus in the cpuset. Generalizing this behavior to all > the tasks irrespective if they have explicitly set cpus affinity before will > disallow this use case. This is nasty. The real solution here is separating out what user requested and the mask that cpuset (or cpu hotplug) needs to apply on top. ie. remember what the user requested in a separate cpumask and compute the intersection into p->cpus_maks whenever something changes and apply fallbacks on that final mask. Multiple parties updating the same variable is never gonna lead to anything consistent and we're patching up for whatever the immediate use case seems to need at the moment. That said, I'm not necessarily against patching it up but if you're interested in delving into it deeper, that'd be great. Thanks. -- tejun
