Re: [PATCH 4/6] kvm tools: Add rwlock wrapper

Paul E. McKenney
2011-05-30T03:13:04Z

On Sun, May 29, 2011 at 09:54:50PM +0200, Ingo Molnar wrote:
>
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
>
> > And the other reason that you want to mark the readers is for debug
> > purposes. Murphy being who he is, you will some day need to check
> > for someone calling the "OK to update" function while they are
> > acting as a reader.
>
> Correct. In one of the previous mails i suggested a debug mode that
> switches it all to pthread rwlocks.
>
> We do not want to lose the identify of what the read paths are: this
> could grow into a BKL-alike nasty-to-fix assumption over a couple of
> years! Then if someone finds a usecase that intensifies the frequency
> of one of the key writepaths, we'll be in trouble ...

"BKR" -- Big Kernel Reader! ;-)

Thanx, Paul