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Groups > linux.kernel > #1724940
| From | Byungchul Park <byungchul.park@lge.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation |
| Date | 2017-09-01 12:20 +0200 |
| Message-ID | <ukRdn-2z9-5@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <uksI3-38N-43@gated-at.bofh.it> <uksRI-3bX-33@gated-at.bofh.it> <uktb4-3io-23@gated-at.bofh.it> <ukJzb-5GI-15@gated-at.bofh.it> <ukQKm-25K-17@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Sep 01, 2017 at 11:47:47AM +0200, Peter Zijlstra wrote:
> On Fri, Sep 01, 2017 at 11:05:12AM +0900, Byungchul Park wrote:
> > On Thu, Aug 31, 2017 at 10:34:53AM +0200, Peter Zijlstra wrote:
> > > On Thu, Aug 31, 2017 at 05:15:01PM +0900, Byungchul Park wrote:
> > > > It's not important. Ok, check the following, instead:
> > > >
> > > > context X context Y
> > > > --------- ---------
> > > > wait_for_completion(C)
> > > > acquire(A)
> > > > release(A)
> > > > process_one_work()
> > > > acquire(B)
> > > > release(B)
> > > > work->fn()
> > > > complete(C)
> > > >
> > > > We don't need to lose C->A and C->B dependencies unnecessarily.
> > >
> > > I really can't be arsed about them. Its really only the first few works
> > > that will retain that dependency anyway, even if you were to retain
> > > them.
> >
> > Wrong.
> >
> > Every 'work' doing complete() for different classes of completion
> > variable suffers from losing valuable dependencies, every time, not
> > first few ones.
>
> The moment you overrun the history array its gone. So yes, only the
It would be gone _only_ at the time the history overrun, and then it
will be built again. So, you are wrong.
Let me show you an example: (I hope you also show examples.)
context X context Y
--------- ---------
wait_for_completion(D)
while (true)
acquire(A)
release(A)
process_one_work()
acquire(B)
release(B)
work->fn()
complete(C)
acquire(D)
release(D)
When happening an overrun in a 'work', 'A' and 'B' will be gone _only_
at the time, and then 'D', 'A' and 'B' will be queued into the xhlock
*again* from the next loop on, and they can be used to generate useful
dependencies again.
You are being confused now. Acquisitions we are focusing now are not
_stacked_ like hlocks, but _accumulated_ continuously onto the ring
buffer e.i. xhlock array.
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Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-29 11:10 +0200
[tip:locking/core] locking/lockdep: Untangle xhlock history save/restore from task independence tip-bot for Peter Zijlstra <tipbot@zytor.com> - 2017-08-29 16:30 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <max.byungchul.park@gmail.com> - 2017-08-29 18:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-29 20:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-08-30 04:20 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-08-30 09:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-30 11:00 +0200
RE: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation "Byungchul Park" <byungchul.park@lge.com> - 2017-08-30 11:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-30 11:20 +0200
RE: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation "Byungchul Park" <byungchul.park@lge.com> - 2017-08-30 11:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-30 11:20 +0200
RE: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation "Byungchul Park" <byungchul.park@lge.com> - 2017-08-30 11:30 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-08-30 13:30 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <max.byungchul.park@gmail.com> - 2017-08-30 15:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-08-31 09:30 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-31 10:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-08-31 10:20 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-31 10:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-01 04:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-01 11:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-01 12:20 +0200
RE: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation 박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com) <byungchul.park@lge.com> - 2017-09-01 14:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-01 14:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <max.byungchul.park@gmail.com> - 2017-09-01 16:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-01 18:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-04 03:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-04 04:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-04 13:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 02:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-05 09:10 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-05 09:20 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 11:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-05 11:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 12:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 13:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-05 15:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-06 02:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Boqun Feng <boqun.feng@gmail.com> - 2017-09-06 02:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-06 03:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-07 02:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-07 02:20 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-06 02:50 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-09-05 13:00 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 13:30 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Byungchul Park <byungchul.park@lge.com> - 2017-09-05 10:40 +0200
Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Peter Zijlstra <peterz@infradead.org> - 2017-08-31 10:10 +0200
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