On Wed, 18 Oct 2017, Paul E. McKenney wrote: > > Well, you could explicitly mention that in the multi-thread case, this > > means all accesses to the shared variable had better use READ_ONCE() or > > WRITE_ONCE(). > > Like this? > > Thanx, Paul > > ------------------------------------------------------------------------ > > d. If there are multiple CPUs, accesses to shared variables > should use READ_ONCE() and WRITE_ONCE() or stronger > to prevent load/store tearing, load/store fusing, and > invented loads and stores. There are exceptions to > this rule, for example: > > i. When there is no possibility of a given > shared variable being updated, for example, > while holding the update-side lock, reads > from that variable need not use READ_ONCE(). > > ii. When there is no possibility of a given shared > variable being either read or updated, for > example, when running during early boot, reads > from that variable need not use READ_ONCE() and > writes to that variable need not use WRITE_ONCE().
Yeah, except that you mean being read or updated by another thread. Alan
