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

From: Peter Zijlstra
Date: Wed May 14 2014 - 10:54:01 EST


On Wed, May 14, 2014 at 07:27:04AM -0700, Davidlohr Bueso 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
> >
> > rwsem: Add comments to explain the meaning of the rwsem's count field
> >
> > It took me quite a while to understand how rwsem's count field
> > mainifested itself in different scenarios.
> >
> > Add comments to provide a quick reference to the the rwsem's count
> > field for each scenario where readers and writers are contending
> > for the lock.
> >
> > Hopefully it will be useful for future maintenance of the code and
> > for people to get up to speed on how the logic in the code works.
>
> sigh, after this commit, the opt spin patch no longer applies, I'm
> rebasing and send out v5.

No worries, fixed it already.

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