Date: Wed, 27 Mar 2002 17:14:43 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Jake Burkholder <jake@locore.ca> Cc: arch@FreeBSD.ORG, Julian Elischer <julian@elischer.org> Subject: Re: SMP safe reference counting Message-ID: <XFMail.20020327171443.jhb@FreeBSD.org> In-Reply-To: <20020327171351.E31836@locore.ca>
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On 27-Mar-2002 Jake Burkholder wrote: > Apparently, On Wed, Mar 27, 2002 at 04:51:57PM -0500, > John Baldwin said words to the effect of; > >> >> On 27-Mar-2002 Julian Elischer wrote: >> > >> > [please remove -smp from your reply] >> > >> > Once again on the SMP list a lock is being used to make a reference count >> > safe. I'd like to re-raise the issue of a safe reference counting >> > fascility. >> > >> > what would be the semantics? >> >> I have refcount.patch :) What would be nice is to first implement >> atomic_fetchadd() (xadd on 486+, some hack on 386, fetchadd on ia64, similar >> to >> atomic_add on sparc64, alpha, and powerpc I believe, basically it would add >> a >> value to a memory location and return the result). You can then use taht >> for >> the reference_release (or whatever you call it). We could also use that to >> get >> rid of the really bloated debug version that uses a mutex and have a much >> smaller debug version that still uses atomic ops. > > We support 386 still? If you compile a custom kernel. :) -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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