From owner-cvs-all  Thu Oct  1 13:06:40 1998
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	Thu, 1 Oct 1998 16:41:49 +0200 (CEST)
To: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
cc: Alex Nash <nash@mcs.net>, John Birrell <jb@FreeBSD.ORG>,
        cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject: Re: cvs commit: src/lib/libc_r/uthread uthread_gc.c Makefile.inc uthread_init.c uthread_find_thread.c uthread_kern.c uthread_create.c uthread_exit.c 
In-reply-to: Your message of "Thu, 01 Oct 1998 10:40:22 EDT."
             <199810011440.KAA20723@khavrinen.lcs.mit.edu> 
Date: Thu, 01 Oct 1998 16:41:49 +0200
Message-ID: <2346.907252909@critter.freebsd.dk>
From: Poul-Henning Kamp <phk@critter.freebsd.dk>
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You guys are overlooking what the variable is there for.

In message <199810011440.KAA20723@khavrinen.lcs.mit.edu>, Garrett Wollman write
s:
><<On Thu, 1 Oct 1998 09:28:57 -0500, Alex Nash <nash@mcs.net> said:
>
>> On Thu, Oct 01, 1998 at 10:02:06AM +0200, Poul-Henning Kamp wrote:
>>> Alex, can we constrain ourselves to >actual< problems rather than
>>> theoretically-possible-on-really-stupid-machines-problems ?
>
>> The atomicity of malloc_active++ is compiler dependent, not
>> really-stupid-machine dependent.
>
>And, in particular, it may not be atomic on a three-operand RISC
>machine.  Imagine the following code sequence on an imaginary
>processor:
>
>addil	$malloc_active, %r0, %r1
>addl	(%r1), %r0, %r2
>addil	$1, %r2, %r3
>addl	%r3, %r0, (%r1)
>
>-GAWollman
>
>--
>Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
>wollman@lcs.mit.edu  | O Siem / The fires of freedom 
>Opinions not those of| Dance in the burning flame
>MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick
>

--
Poul-Henning Kamp             FreeBSD coreteam member
phk@FreeBSD.ORG               "Real hackers run -current on their laptop."
"ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal