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Date:      Wed, 10 Jan 2001 21:27:38 -0700
From:      "Justin T. Gibbs" <gibbs@scsiguy.com>
To:        John Baldwin <jhb@FreeBSD.org>
Cc:        =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@club-internet.fr>, Jake Burkholder <jake@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Bruce Evans <bde@zeta.org.au>
Subject:   Re: cvs commit: src/sys/alpha/alpha interrupt.c machdep.c mp_mac 
Message-ID:  <200101110428.f0B4Rcs23445@aslan.scsiguy.com>
In-Reply-To: Your message of "Wed, 10 Jan 2001 15:53:58 PST." <XFMail.010110155358.jhb@FreeBSD.org> 

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>No, shared variables are just variables.  Here is the problem.  There is=
 no
>'curproc' variable.  There is a gd_curproc member of a struct globaldata=
, and
>each CPU has a struct globaldata tied to it.  We can obtain it via
>PCPU_GET(curproc), or set it via PCPU_SET(curproc, myproc).  Having a 'c=
urproc
>'
>"magic" variable that doesn't exist that we assume we can read and write=
 to
>like any other variable is a lot more hokie than admitting that we are
>accessing a special variable in a special way.

Anyone touching these variables had better understand what they are for
and how they operate.  I think our developers are smart enough to underst=
and
this without ugly upper-case macros.  Heck "errno" is not spelled
PTHREAD_GET(errno), or PTHREAD_SET(errno, error) and still people seem
to be able to write useful threaded apps. 8-)

The only thing that worries me about curproc and others like it is
that the macros can polute the kernel name space.  Just try using "curren=
t"
as a local variable or structure field in linux x86 to see what I mean.
8-)

--
Justin



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