On Wed, Jun 01, 2016 at 02:45:41PM +0200, Peter Zijlstra wrote: > On Wed, Jun 01, 2016 at 01:13:33PM +0100, Will Deacon wrote: > > On Wed, Jun 01, 2016 at 02:06:54PM +0200, Peter Zijlstra wrote: > > > > Works for me; but that would loose using cmpwait() for > > > !smp_cond_load_acquire() spins, you fine with that? > > > > > > The two conversions in the patch were both !acquire spins. > > > > Maybe we could go the whole hog and add smp_cond_load_relaxed? > > What about say the cmpxchg loops in queued_write_lock_slowpath() > ? Would that be something you'd like to use wfe for?
Without actually running the code on real hardware, it's hard to say for sure. I notice that those loops are using cpu_relax_lowlatency at present and we *know* that we're next in the queue (i.e. we're just waiting for existing readers to drain), so the benefit of wfe is somewhat questionable here and I don't think we'd want to add that initially. Will -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
