Date: Thu, 1 Oct 1998 10:40:22 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Alex Nash <nash@mcs.net> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, 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 Message-ID: <199810011440.KAA20723@khavrinen.lcs.mit.edu> In-Reply-To: <19981001092857.C7057@mcs.net> References: <19980930192221.S9697@pr.mcs.net> <368.907228926@critter.freebsd.dk> <19981001092857.C7057@mcs.net>
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<<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
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