That makes them a *lot* slower on some systems. And most of the
set_bits in the kernel don't need strong ordering.
difference with versions with `__` prefix (__set_bit(), for example)?
Just adding the comments will lead to creating different functions
with gurantees by everyone who need it in all over the kernel. Is it
the right thing? In some places in SCST we heavy rely on non-ordering
guarantees.
Better add lots of memory barriers then.