On Thu, Feb 09, 2017 at 07:57:27AM +0100, Ingo Molnar wrote: > And -rt would do something like this in migration_disable()/enable(): > > t->cpus_ptr = &cpumask_of(task_cpu(p)); > t->nr_cpus = 1; > > ... > > t->cpus_ptr = &t->cpus_mask; > t->nr_cpus = cpumask_weight(t->cpus_mask); > > In addition to that we could cache the weight of the cpumask as an additional > optimization: > > t->cpus_ptr = &t->cpus_mask; > t->nr_cpus = t->cpus_mask_weight; > > It all looks like a pretty natural construct to me. The migration_disabled() > flag > spreads almost a hundred branches all across the scheduler.
Could work I suppose. But please then implement this instead of ripping out the current thing, because taking out the accessors leaves RT in a bind without recourse.
