On Thu, Jul 06, 2017 at 08:34:27AM -0700, Christoph Hellwig wrote: > On Thu, Jul 06, 2017 at 09:55:03AM +0100, Will Deacon wrote: > > Agreed on the indirection; it feels like this is something that should be in > > the vDSO, which could use the cmpxchg instruction if it's available, or > > otherwise just uses plain loads and stores. > > Even that seems like a lot of indirection for something that is in > the critical fast path for synchronization. I really can't understand > how a new ISA / ABI could even come up with an idea as stupid as making > essential synchronization primitives optional. No disagreement there! Will
