On Sat, Jul 08, 2017 at 10:43:24AM +0200, Ingo Molnar wrote:

* Paul E. McKenney [off-list ref] wrote:

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On Fri, Jul 07, 2017 at 10:31:28AM +0200, Ingo Molnar wrote:

[ . . . ]

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In fact I'd argue that any future high performance spin_unlock_wait() user is 
probably better off open coding the unlock-wait poll loop (and possibly thinking 
hard about eliminating it altogether). If such patterns pop up in the kernel we 
can think about consolidating them into a single read-only primitive again.

I would like any reintroduction to include a header comment saying exactly
what the consolidated primitive actually does and does not do.  ;-)

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I.e. I think the proposed changes are doing no harm, and the unavailability of a 
generic primitive does not hinder future optimizations either in any significant 
fashion.

I will have a v3 with updated comments from Manfred.  Thoughts on when/where
to push this?

Once everyone agrees I can apply it to the locking tree. I think PeterZ's was the 
only objection?

Oleg wasn't all that happy, either, but he did supply the relevant patch.

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The reason I ask is if this does not go in during this merge window, I need
to fix the header comment on spin_unlock_wait().

Can try it next week after some testing - let's see how busy things get for Linus 
in the merge window?

Sounds good!  Either way is fine with me.

							Thanx, Paul