On Tue, Aug 23, 2016 at 02:53:07PM -0400, Linus Torvalds wrote: > On Tue, Aug 23, 2016 at 12:17 PM, Davidlohr Bueso <[email protected]> wrote: > > > >> 46 files changed, 160 insertions(+), 1298 deletions(-) > > > > Oh my. > > Yeah, that looks like a pretty compelling argument right there, if > there isn't any other really major downside to this... > > Peter, is there some downside that isn't obvious? Like "Well, this > does regress performance because it now always does X"?
The biggest difference is the mutex fast paths, where they were a single atomic and branch they're now a bit bigger. How much that matters in practise is something that we'll have to benchmark a bit. Esp. the mutex_lock() fast-path now also needs to load current, which at least should be fairly hot but can still be a number of dependent loads on some archs.
