On Sun, Jun 26, 2016 at 12:59:01PM +0800, panxinhui wrote: > > > 在 2016年6月26日，03:12，Peter Zijlstra <[email protected]> 写道： > > > > On Sun, Jun 26, 2016 at 01:27:51AM +0800, panxinhui wrote: > > > >> by the way I still think mutex_unlock has a big overload too. > > > > Do you mean overhead? > > > oh, maybe you are right.
> mutex_unlock ’s implementation uses inc_return variant on ppc, and > that’s expensive. I am thinking of using cmpxchg instead. That statement doesn't make any sense. PPC is an LL/SC arch, inc_return and cmpxchg are the 'same' LL/SC loop.
