Hi, Peter, 04.06.2014, 14:41, "Peter Zijlstra" <[email protected]>: > A while ago I did a similar patch for some debugging, but looking at it > again today I realized we should probably fix this anyway. > > --- > Subject: sched: Fix migration_cpu_stop() return value > > There are a number of migration_cpu_stop() users; and some actually care > about the success of the migration. So report this. > > In particular migrate_task_to() as used from task_numa_migrate() > actually tests this return value. > > Also change set_cpus_allowed_ptr() to propagate this return value, since > it already returns other errors. > > Cc: Lai Jiangshan <[email protected]> > Cc: Ingo Molnar <[email protected]> > Signed-off-by: Peter Zijlstra <[email protected]> > --- > kernel/sched/core.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) (snipped everything because of bad email editor)
In set_cpus_allowed_ptr() p->on_rq branch can not fail. We've changed affinity and released rq's lock, so task can migrate on allowed cpu only (even if migration_cpu_stop fails). And it's a little ambiguously how user should react on this EAGAIN. Regards, Kirill. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
