On 2020-06-17 17:49:48 [-0500], Scott Wood wrote: > > Makes sense, but what about the rest of the checks? Further down there is > > > > /* Can the task run on the task's current CPU? If so, we're done > > */ > > if (cpumask_test_cpu(task_cpu(p), new_mask)) > > goto out; > > > > If the task is currently migrate disabled and for some stupid reason it > > gets affined elsewhere, we could try to move it out - which AFAICT we > > don't > > want to do because migrate disabled. So I suppose you'd want an extra > > bailout condition here when the task is migrate disabled. > > > > ISTR in RT you do re-check the affinity and potentially move the task away > > when re-enabling migration, so that should work out all fine. > > On RT the above test is: > > /* Can the task run on the task's current CPU? If so, we're done */ > if (cpumask_test_cpu(task_cpu(p), new_mask) || > p->cpus_ptr != &p->cpus_mask) > goto out; > > ...so we do bail out if we're migrate disabled.
correct. There is a complete migrate_disable() patch in the RT queue which has to wait. This patch however looked to be independent of that and could "fix" the pointer part which is already here so I sent it. > -Scott Sebastian
