On Wed, Dec 20, 2017 at 04:01:10PM +0100, Peter Zijlstra wrote: > Well, you shouldn't mix atomic and non-atomic ops to the same word, > that's asking for trouble. > > But why don't you do something like: > > nohz_kick() > > flags = NOHZ_STAT; > if (!only_update) > flags |= NOHZ_BALANCE; > > atomic_long_or(flags, &nohz_cpu(cpu)); > > > nohz_idle_balance() > > unsigned long do_flags = > atomic_long_fetch_andnot(NOHZ_BALANCE|NOHZ_STAT, &nohz_flags(cpu)); > > if (do_flags & NOHZ_STAT) > update_blocked_stuff(); > > if (do_flags & NOHZ_BALANCE) > rebalance_domains(); > > That way its far more readable.
we could use atomic_t too, there's not that many flags in there, the only reason its long is because of that bitmap crud.
