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Groups > linux.kernel > #1623230
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() |
| Date | 2017-04-13 20:00 +0200 |
| Message-ID | <tvRce-6mR-11@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <tvPDs-5oA-13@gated-at.bofh.it> <tvPN8-5sD-23@gated-at.bofh.it> <tvQg9-5H7-13@gated-at.bofh.it> <tvQzw-66m-19@gated-at.bofh.it> <tvR2y-6iE-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Apr 13, 2017 at 10:39:51AM -0700, Paul E. McKenney wrote:
> Well, if there are no objections, I will fix up the smp_mb__before_atomic()
> and smp_mb__after_atomic() pieces.
Feel free.
> I suppose that one alternative is the new variant of kerneldoc, though
> very few of these functions have comment headers, let alone kerneldoc
> headers. Which reminds me, the question of spin_unlock_wait() and
> spin_is_locked() semantics came up a bit ago. Here is what I believe
> to be the case. Does this match others' expectations?
>
> o spin_unlock_wait() semantics:
>
> 1. Any access in any critical section prior to the
> spin_unlock_wait() is visible to all code following
> (in program order) the spin_unlock_wait().
>
> 2. Any access prior (in program order) to the
> spin_unlock_wait() is visible to any critical
> section following the spin_unlock_wait().
>
> o spin_is_locked() semantics: Half of spin_unlock_wait(),
> but only if it returns false:
>
> 1. Any access in any critical section prior to the
> spin_unlock_wait() is visible to all code following
> (in program order) the spin_unlock_wait().
Urgh.. yes those are pain. The best advise is to not use them.
055ce0fd1b86 ("locking/qspinlock: Add comments")
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[PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-12 19:00 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 11:20 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 11:40 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 18:20 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 18:30 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 19:00 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 19:20 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 19:50 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 20:00 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-13 20:10 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-20 01:30 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-20 01:30 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-20 13:20 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-20 17:10 +0200
Re: [PATCH tip/core/rcu 07/13] rcu: Add smp_mb__after_atomic() to sync_exp_work_done() Peter Zijlstra <peterz@infradead.org> - 2017-04-20 17:10 +0200
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