> Either way, that does look like a reasonable answer. I had looked at > the various one-line wrappers around slot_handle_level_range() and > thought "hm, those should be inline", but I hadn't made the next step > and pondered putting the whole thing inline. We'll give it a spin and > work out where the next performance bottleneck is. Thanks.
In addition the problem with switch() is that gcc might decide in some cases that the best way to implement your switch is an indirect call from a lookup table. For the simple case how about wrapping the if into call_likely(foo->bar, usualfunction, args) as a companion to foo->bar(args) that can resolve to nothing special on architectures that don't need it, an if/else case on platforms with spectre, and potentially clever stuff on any platform where you can beat the compiler by knowing probabilities it can't infer ? Alan