On Mon, Aug 28, 2017 at 08:55:53AM +0200, Peter Zijlstra wrote: > On Fri, Aug 25, 2017 at 05:41:03PM +0900, Byungchul Park wrote: > > Hello all, > > > > This is _RFC_. > > > > I want to request for comments about if it's reasonable conceptually. If > > yes, I want to resend after working it more carefully. > > > > Could you let me know your opinions about this? > > > > ----->8----- > > From 448360c343477fff63df766544eec4620657a59e Mon Sep 17 00:00:00 2001 > > From: Byungchul Park <byungchul.p...@lge.com> > > Date: Fri, 25 Aug 2017 17:35:07 +0900 > > Subject: [RFC] workqueue: remove manual lockdep uses to detect deadlocks > > > > We introduced the following commit to detect deadlocks caused by > > wait_for_completion() in flush_{workqueue, work}() and other locks. But > > now LOCKDEP_COMPLETIONS is introduced, such works are automatically done > > by LOCKDEP_COMPLETIONS. So it doesn't have to be done manually anymore. > > Removed it. > > > > No.. the existing annotation is strictly better because it will _always_ > warn. It doesn't need to first observe things just right.
In addition, the existing annotation is never good, but just able to detect deadlocks aggresively. However, it's inevitable to create false dependencies. I mean some dependencies between work/wq and any locks inside of each work might be false ones sometimes.