Messages in this thread | | | Date | Tue, 29 Aug 2017 09:23:33 +0900 | From | Byungchul Park <> | Subject | Re: [RFC] workqueue: remove manual lockdep uses to detect deadlocks |
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On Fri, Aug 25, 2017 at 06:34:43AM -0700, Tejun Heo 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.park@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. > > I'm not following lockdep development, so can't really comment but if > you're saying that wq can retain the same level of protection while > not having explicit annotations, conceptually, it's of course great. > However, how would it distinguish things like flushing another work > item on a workqueue w/ max_active of 1?
Do you mean the following?
process_one_work() acquire(W1) <---------+- distinguishable? work->fn() | flush_work(W2) | acquire(W2) <---+ release(W2) release(W1)
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