From: Kaz Kylheku <kaz@ashi.footprints.net> Subject: Re: [libc-alpha] Re: PATCH: Fix ll/sc for mips Date: Thu, 31 Jan 2002 20:02:25 -0800 (PST) > On Fri, 1 Feb 2002, Hiroyuki Machida wrote: > > Please note that "sc" may fail even if nobody write the > > variable. (See P.211 "8.4.2 Load-Linked/Sotre-Conditional" of "See > > MIPS RUN" for more detail.) > > So, after your patch applied, compare_and_swap() may fail, even if > > *p is equal to oldval. > > I can't think of anything that will break because of this, as long > as the compare_and_swap eventually succeeds on some subsequent trial. > If the atomic operation has to abort for some reason other than *p being > unequal to oldval, that should be cool. I mean that this patch breaks the spec of compare_and_swap(). In most case, this patch may works as Kaz said. If this patch have no side-effect to any application, it's ok to apply the patch. But we can't know how to use compare_and_swap() in all aplications in a whole world. So we have to follow the spec. --- Hiroyuki Machida Sony Corp.
