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Re: [PATCH] Documentation: Remove misleading examples of the barriers in wake_*()

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On Mon, Oct 12, 2015 at 01:54:38PM +0200, Peter Zijlstra wrote:
> On Mon, Oct 12, 2015 at 05:06:36PM +0800, Boqun Feng wrote:
> > Understood.
> > 
> > But, IMO, the position of this section is already misleading:
> > 
> > (*) Implicit kernel memory barriers.
> >      - Locking functions.
> >      - Interrupt disabling functions.
> >    ->- Sleep and wake-up functions.<-
> >      - Miscellaneous functions.
> > 
> > I read it as that sleep and wake-up functions provide some kernel memory
> > barriers which we can use *externally*(outside sleep/wakeup themselves).
> 
> I think it is useful to state that the primitives handle the ordering
> between the waker and wakee wrt the 'blocking' state.
> 

I agree that's useful, however, the 'blocking' state is something
internal for sleep and wakeup, right? Not sure whether the users of
wake_up() and wait_event() will care much about this or they need to
understand that detailedly to use wake_up() and wait_event() correctly.

I treat this part of memory-barriers.txt as an API document to describe
the implicit barriers in some primitives, which can be used *externally*
by someone, but anyway, that's just my own opinion ;-)

> But I've not put much thought into wording. I wanted to finish process
> order 'comment' patch first.

Of course. Actually your 'comment' patch is the reason why I think this
section may be removed.

Regards,
Boqun

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Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Peter Zijlstra <peterz@infradead.org> - 2015-10-06 18:10 +0200
  Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Boqun Feng <boqun.feng@gmail.com> - 2015-10-11 17:30 +0200
    Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-10-12 02:50 +0200
      Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Boqun Feng <boqun.feng@gmail.com> - 2015-10-12 11:10 +0200
        Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Peter Zijlstra <peterz@infradead.org> - 2015-10-12 14:00 +0200
          Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Boqun Feng <boqun.feng@gmail.com> - 2015-10-12 15:10 +0200
            Re: [PATCH] Documentation: Remove misleading examples of the  barriers in wake_*() Peter Zijlstra <peterz@infradead.org> - 2015-10-12 18:30 +0200

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