On Mon, Jul 15, 2013 at 05:12:31PM -0700, Davidlohr Bueso wrote: > On Mon, 2013-07-15 at 16:08 -0700, Andrew Morton wrote: > > On Mon, 15 Jul 2013 17:24:32 +1000 David Gibson wrote: > > > > > I have previously proposed a correct method of improving scalability, > > > although it doesn't eliminate the lock. That's to use a set of hashed > > > mutexes. > > > > Yep - hashing the mutexes is an obvious and nicely localized way of > > improving this. It's a tweak, not a design change. > > > > The changelog should describe the choice of the hash key with great > > precision, please. It's important and is the first thing which > > reviewers and readers will zoom in on. Yeah, that is important. I no longer have much interest in the result of this patch, so I'll leave it to others to do the forward port and cleanup. But I will point out the gotcha here is that the hash key needs to be based on (address_space & file offset) for MAP_SHARED, but (mm & address) for MAP_PRIVATE. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson