Date: Mon, 24 May 2004 10:38:19 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-arch@FreeBSD.org Cc: Julian Elischer <julian@elischer.org> Subject: Re: atomic reference counting primatives. Message-ID: <200405241038.19589.jhb@FreeBSD.org> In-Reply-To: <p06020404bcd44faaef2f@[128.113.24.47]> References: <Pine.BSF.4.21.0405201340590.72391-100000@InterJet.elischer.org> <p06020404bcd44faaef2f@[128.113.24.47]>
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On Friday 21 May 2004 08:44 pm, Garance A Drosihn wrote: > At 1:56 PM -0700 5/20/04, Julian Elischer wrote: > >This has been raised before but I have come across uses for > >it again and again so I'm raising it again. JHB once posted > >some atomic reference counting primitives. (Do you still have > >them John?) Alfred once said he had some somewhere too, and > >others have commented on this before, but we still don't seem > >to have any. > > Btw, does this thread have anything to do with the present > buuldworld-breakage for sparc64? I notice the compile-time > errors are something like: No. > /usr/src/lib/libthr/thread/thr_cancel.c: In function `testcancel': > /usr/src/lib/libthr/thread/thr_cancel.c:123: warning: passing > arg 1 of `atomic_cmpset_int' from incompatible pointer type > > My guess is that this is related to Mike's change to "Make libthr > async-signal-safe without costly signal masking. [...etc...]". > > This breakage underlines one reason that it would be mighty > convenient to have some "official" set of primitives. It is > one thing if a developer has to roll-their-own solution for > i386, but somewhat more challenging if that solution has to > work across a half-dozen different hardware platforms. atomic_cmpset() is an "official" primitive. The problem is that Mike is using an enum and assuming that all enum's are ints which is not necessarily true. The code should perhaps use an int with #define's instead to guarantee that the variable is an int and not a short, char, or long. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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