On Wed, Mar 01, 2017 at 04:11:48PM +0000, Chris Wilson wrote: > On Wed, Mar 01, 2017 at 04:54:14PM +0100, Peter Zijlstra wrote: > > On Wed, Mar 01, 2017 at 11:40:43PM +0800, Fengguang Wu wrote: > > > Thanks for the patch! I applied the patch on top of "locking/ww_mutex: > > > Add kselftests for ww_mutex stress", and find no "bad unlock balance > > > detected" but this warning. Attached is the new dmesg which is a bit > > > large due to lots of repeated errors. > > > > So with all the various patches it works for me. > > > > I also have the following on top; which I did when I was looking through > > this code trying to figure out wth was happening. > > > > Chris, does this make sense to you? > > > > It makes each loop a fully new 'instance', otherwise we'll never update > > the ww_class->stamp and the threads will aways have the same order. > > Sounds ok, I just thought the stamp order of the threads was > immaterial - with each test doing a different sequence of locks and each > being identical in behaviour, it would not matter which had priority, > there would have be some shuffling no matter waht. However, for the > purpose of testing, having each iteration be a new locking instance does > make it behaviour more like a typical user.
Correcting myself, the workers didn't reorder the locks, so changing the stamp does make the test more interesting. -Chris -- Chris Wilson, Intel Open Source Technology Centre