Messages in this thread |  | | From | Byungchul Park <> | Date | Sat, 26 Aug 2017 00:49:26 +0900 | Subject | Re: [RFC] workqueue: remove manual lockdep uses to detect deadlocks |
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On Fri, Aug 25, 2017 at 10:34 PM, Tejun Heo <tj@kernel.org> 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.
Well.. I don't think it's the same level currently. But, I can make it with some modification. I expect the wq code to become much simpler.
> However, how would it distinguish things like flushing another work
I think it must be distinguished with what it actually waits for, e.i. completion variables instead of work or wq. I will make it next week and let you know.
> item on a workqueue w/ max_active of 1?
I will answer it wrt max_active == 1 next week. I need to review wq code.
-- Thanks, Byungchul
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