Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!samsung!think!barmar
From: barmar@think.com (Barry Margolin)
Newsgroups: comp.object
Subject: Re: Garbage collection
Keywords: Garbage collection, object management
Message-ID: <34484@news.Think.COM>
Date: 6 Mar 90 07:01:03 GMT
References: <52045@microsoft.UUCP> <25f324e9.1488@polyslo.CalPoly.EDU>
Sender: news@Think.COM
Reply-To: barmar@nugodot.think.com.UUCP (Barry Margolin)
Distribution: usa
Organization: Thinking Machines Corporation, Cambridge MA, USA
Lines: 18

In article <25f324e9.1488@polyslo.CalPoly.EDU> ttwang@polyslo.CalPoly.EDU (Thomas Wang) writes:
>  If the language would access things through
>handles, then a portable GC can be written with good enough performance for
>it to be useful.

At the expense of doubling the number of memory references for every
pointer dereference.

The Macintosh system has a reasonable compromise.  They encourage use of
handles, but provide a LockHandle function.  You lock a handle around a
section of code that uses that pointer extensively (e.g. an inner loop),
and only dereference the handle once, right after the lock.  If a GC
happens during that section of code the locked object won't be moved.
--
Barry Margolin, Thinking Machines Corp.

barmar@think.com
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