On Mon, Dec 17, 2018 at 12:55:35PM -0800, Andi Kleen wrote: > On Mon, Dec 17, 2018 at 08:29:38PM +0100, Peter Zijlstra wrote: > > When/if we get the LTO trainwreck sorted -- which very much includes > > getting that memory-order-consume fixed -- we can revisit all that. > > What do you mean? I'm not aware of any LTO problems with memory-order-consume?
The compiler is basically allowed to break RCU (and anything else that depends on read-read dependencies). LTO makes it _far_ more likely this happens. We need guarantees (and possible switches) from the compiler folks that this will not happen before I'll retract my NAK from any LTO enabling.
