On 19/10/20 17:32, Tao Zhou wrote: > Hi Valentin, >> >> Side thought: don't we need to NULL p->migration_pending in __sched_fork()? >> > > No need, if fork happen, the forked task will inherit that pending.
Which is what I'm worrying about. I think we can ignore migrate_disable() for now and just consider a task fork()'ing while another tries to sched_setaffinity() it; say the fork() happens just after the pending has been installed. Unless I'm overthinking it, we could end up with a dangling pending reference, which will wreck havock to any later affine_move_task() (see the if (p->migration_pending) paths). > If pending is NULL, when call SCA, it will install pending. If pending > is not NULL, it means it is in migrate region and wait for complete. > If NULL pending in __sched_fork() it will install a new pending in this > case which is not right to me. Add a flag(ENABLE_MIGRATE) to arg will > differ the path where in. > > Always likely miss something. > > Tao >
