vm_page_t related KBI [Was: Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3]

[Kostik Belousov]

On Fri, Nov 18, 2011 at 11:56:55AM +0100, Attilio Rao wrote:
> 2011/11/18 Kostik Belousov <kostikbel at gmail.com>:
> > On Fri, Nov 18, 2011 at 11:40:28AM +0100, Attilio Rao wrote:
> >> 2011/11/16 Kostik Belousov <kostikbel at gmail.com>:
> >> > On Tue, Nov 15, 2011 at 07:15:01PM +0100, Attilio Rao wrote:
> >> >> 2011/11/7 Kostik Belousov <kostikbel at gmail.com>:
> >> >> > On Mon, Nov 07, 2011 at 11:45:38AM -0600, Alan Cox wrote:
> >> >> >> Ok.  I'll offer one final suggestion.  Please consider an alternative
> >> >> >> suffix to "func".  Perhaps, "kbi" or "KBI".  In other words, something
> >> >> >> that hints at the function's reason for existing.
> >> >> >
> >> >> > Sure. Below is the extraction of only vm_page_lock() bits, together
> >> >> > with the suggested rename. When Attilio provides the promised simplification
> >> >> > of the mutex KPI, this can be reduced.
> >> >>
> >> >> My tentative patch is here:
> >> >> http://www.freebsd.org/~attilio/mutexfileline.patch
> >> >>
> >> >> I need to make more compile testing later, but it already compiles
> >> >> GENERIC + modules fine on HEAD.
> >> >>
> >> >> The patch provides a common entrypoint, option independent, for both
> >> >> fast case and debug/compat case.
> >> >> Additively, it almost entirely fixes the standard violation of the
> >> >> reserved namespace, as you described (the notable exception being the
> >> >> macro used in the fast path, that I want to fix as well, but in a
> >> >> separate commit).
> >> >>
> >> >> Now the file/line couplet can be passed to the "_" suffix variant of
> >> >> the flag functions.
> >> > Yes, this is exactly KPI that I would use when available for the
> >> > vm_page_lock() patch.
> >> >
> >> >>
> >> >> eadler@ reviewed the mutex.h comment.
> >> >>
> >> >> Please let me know what you think about it, as long as we agree on the
> >> >> patch I'll commit it.
> >> > But I also agree with John that imposing large churn due to the elimination
> >> > of the '__' prefix is too late now. At least it will make the change
> >> > non-MFCable. Besides, we already lived with the names for 10+ years.
> >> >
> >> > I will be happy to have the part of the patch that exports the mtx_XXX_(mtx,
> >> > file, line) defines which can be used without taking care of LOCK_DEBUG
> >> > or MUTEX_NOINLINE in the consumer code.
> >>
> >> Ok, this patch should just add the compat stub:
> >> http://www.freebsd.org/~attilio/mutexfileline2.patch
> > Am I right that I would use mtx_lock_(mtx, file, line) etc ?
> > If yes, I am fine with it.
> 
> Yes that is correct.
> 
> However, I'm a bit confused on one aspect: would you mind using
> _mtx_lock_flags() instead?
> If you don't mind the "underscore namespace violation" I think I can
> make a much smaller patch against HEAD for it.
_mtx_lock_flags() is fine. The reserved names start with __ or _[A-Z].

> 
> Otherwise, the one now posted should be ok.
> 
> Attilio
> 
> 
> -- 
> Peace can only be achieved by understanding - A. Einstein
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