On Fri, Jun 03, 2016 at 01:12:50PM +0200, Heiko Carstens wrote: > On Fri, Jun 03, 2016 at 10:48:01AM +0200, Peter Zijlstra wrote: > > On Fri, Jun 03, 2016 at 09:15:44AM +0200, Heiko Carstens wrote: > > > Hi all, > > > > > > the new lockdep chain_key collision detection code triggers quite reliably > > > on s390, so it looks like we need a different iterate_chain_key() > > > implementation? > > > > That too, I have one queued up; but if you can realiably trigger this > > that's 'good' news. Most reports so far have been one offs that people > > could not reproduce. > > > > Let me wake up a bit more, but in the meantime, the below is what I had > > queued. > > > > --- > > Subject: locking,lockdep: Use __jhash_mix for iterate_chain_key > > From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > Date: Mon May 30 18:31:33 CEST 2016 > > > > Use __jhash_mix() to mix the class_idx into the class_key. This > > function provides better mixing than the previously used, home grown > > mix function. > > Ok, thanks! I'll use that then. Unfortunately the new hash function > generates 28 instead of 2 instructions on s390. Yeah, but I doubt you can actually measure the performance difference, lockdep is a pig anyway. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
