On Wed, Jun 05, 2013 at 07:48:01PM -0700, Andrew Morton wrote: > On Thu, 6 Jun 2013 11:45:09 +1000 Dave Chinner <david@xxxxxxxxxxxxx> wrote: > > > Andrew, if you want to push the changes back to generic per-cpu > > counters through to Linus, then I'll write the patches for you. But > > - and this is a big but - I'll only do this if you are going to deal > > with the "performance trumps all other concerns" fanatics over > > whether it should be merged or not. I have better things to do > > with my time have a flamewar over trivial details like this. > > Please view my comments as a critique of the changelog, not of the code. > > There are presumably good (but undisclosed) reasons for going this way, > but this question is so bleeding obvious that the decision should have > been addressed up-front and in good detail. The answer is so bleeding obvious I didn't think it needed to be documented. ;) i.e. implement it the same way that it's sibling is implemented because consistency is good.... > And, preferably, with benchmark numbers. Because it might have been > the wrong decision - stranger things have happened. I've never been able to measure the difference in fast-path performance that can be attributed to the generic CPU counters having more overhead than the special ones. If you've got any workload where the fast-path counter overhead shows up in a profile, I'd be very interested.... Cheers, dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>