On Tue, Dec 05, 2017 at 10:57:00PM +0100, Peter Zijlstra wrote: > On Tue, Dec 05, 2017 at 11:24:49PM +0200, Michael S. Tsirkin wrote: > > READ_ONCE is really all over the place (some code literally replaced all > > memory accesses with READ/WRITE ONCE). > > Yeah, so? Oh my point was I can't just look for READ_ONCE and go *that's the pair*. there are too many of these. At Paul's suggestion I will document the pairing *this read once has a barrier that is paired with that barrier*. > Complain to the compiler people for forcing us into that. In some cases when you end up with all accesses going through read/write once volatile just might better. > > Would an API like WRITE_POINTER()/smp_store_pointer make sense, > > and READ_POINTER for symmetry? > > No, the whole point of the exercise was to get away from the fact that > dependent loads are special. It's a pity that dependent stores are still special. -- MST
