Re: [tip:locking/core] rwsem: Add comments to explain the meaning of the rwsem's count field

[Tim Chen]

On Mon, 2014-05-05 at 19:26 +0200, Ingo Molnar wrote:
> * Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote:
> 
> > On Mon, 2014-05-05 at 01:46 -0700, tip-bot for Tim Chen wrote:
> > > Commit-ID:  3cf2f34e1a3d4d5ff209d087925cf950e52f4805
> > > Gitweb:     http://git.kernel.org/tip/3cf2f34e1a3d4d5ff209d087925cf950e52f4805
> > > Author:     Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> > > AuthorDate: Fri, 2 May 2014 12:53:57 -0700
> > > Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
> > > CommitDate: Sun, 4 May 2014 20:34:26 +0200
> > > 
> > 
> > Ingo,
> > 
> > Can you pick up this version of the patch instead.  I've updated the 
> > comments to reflect all cases for which the rwsem's count is less 
> > than WAITING_BIAS, as Peter has pointed out.
> 
> Please send a delta patch against the one I applied - and also the 
> state diagram suggestion with Peter, once it's clear what form it 
> should take. I've yet to see a state diagram that was inferior to 
> equivalent textual description - is this case an exception to that?
> 

Ingo,

The delta patch is included below.  Thinking a bit more,
the state diagram approach is not necessarily less verbose
because the state is a tuple (count, wait queue state).
After enumerating the states, we may wind up with very similar
to what I have.

Thanks.

Tim

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