From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id AAA25765; Fri, 20 Apr 2001 00:32:44 +0200 (MET DST)
X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f
Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id AAA25824 for <caml-list@pauillac.inria.fr>; Fri, 20 Apr 2001 00:32:43 +0200 (MET DST)
Received: from ext-ch1gw-3.online-age.net (ext-ch1gw-3.online-age.net [216.34.191.37])
	by concorde.inria.fr (8.11.1/8.10.0) with ESMTP id f3JMWfr25343
	for <caml-list@inria.fr>; Fri, 20 Apr 2001 00:32:41 +0200 (MET DST)
Received: from int-ch1gw-2.online-age.net (int-ch1gw-2 [3.159.232.66])
	by ext-ch1gw-3.online-age.net (8.9.3+Sun/8.9.1/990426-RLH) with ESMTP id SAA12752;
	Thu, 19 Apr 2001 18:32:36 -0400 (EDT)
Received: from uswaumsxb4medge.med.ge.com (localhost [127.0.0.1])
	by int-ch1gw-2.online-age.net (8.9.3+Sun/8.9.1/990426-RLH) with ESMTP id SAA12547;
	Thu, 19 Apr 2001 18:32:31 -0400 (EDT)
Received: by USWAUMSXB4MEDGE with Internet Mail Service (5.5.2653.19)
	id <20VN6D1W>; Thu, 19 Apr 2001 17:33:08 -0500
Received: from mrs.mrs.med.ge.com (MRS [3.57.196.1]) by uswaumsxbhmedge.med.ge.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13)
	id 20WCT0C1; Thu, 19 Apr 2001 17:33:00 -0500
Received: (from gurr@localhost)
	by mrs.mrs.med.ge.com (8.9.3+Sun/8.9.3) id PAA21666;
	Thu, 19 Apr 2001 15:31:41 -0700 (PDT)
From: David Gurr <gurr@mrs.med.ge.com>
To: frisch@clipper.ens.fr
Cc: caml-list@inria.fr, gurr@mrs.mrs.med.ge.com
Date: Thu, 19 Apr 2001 15:31:41 -0700 (PDT)
Message-Id: <200104192231.PAA21666@mrs.mrs.med.ge.com>
Subject: GC of custom blocks Re: [Caml-list] User-defined equality on types?
X-Sun-Charset: US-ASCII
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk


Alain Frisch:

> I support this suggestion. The standard equality/ordering/hashing
> functions are often adequate for most of the data structures, and it would
> be useful to use them and just place a hook on specific types to provide
> specialized implementation. It could almost be done with
> the "custom" block tag; the problem is that such blocks are not garbage
> collected.  What about "custom Caml blocks" ?
 
The memory manager Cmm (not to be confused with the IL in ocamlopt)
gives a generic garbage collection interface that allows custom garbage
collectors and custom heaps in such a way that one can use multiple
collectors with multiple heaps including collection of cross heap
pointers.  It is designed to do garbage collection of C++ so it is
complicated by C++ details.  But the basic design is good.  To use the
Cmm design with custom blocks would require 

-- defining a heap interface type

struct heap_operations {
	value (*alloc)(heap h, unsigned long size, mlsize_t mem, mlsize_t max);
	value (*alloc_block)(heap h, tag_t tag, mlsize_t size, mlsize_t mem, mlsize_t max);
	void (*register_root)(heap h, value r);
	void (*unregister_root)(heap h, value r);
	void (*scavenge)(heap h, value v);  /* ie mark, copy, etc */
	void (*collect)(heap h);
	void (*collect_slice)(heap h); /* may need more parameters */
	void (*compact)(heap h);
}; 

-- an addtional operation pointer: 

struct custom_operations {
	...
	void (*traverse)(value v); /* walks v calling scavenge on its pointers */
};

-- using the existing minor and major heaps to implement heap interfaces

value alloc_shr_prime(heap h, tag_t tag, mlsize_t size, mlsize_t mem, mlsize_t max){
	return alloc_shr(tag,size);
}

...

struct heap_operations major_heap = { 
	0, /* you can only alloc standard blocks in the major heap */
	&alloc_shr_prime, 
	&register_global_root_prime,
	... };
	
	
See

	ftp://ftp.di.unipi.it/pub/project/posso/cmm/ 
	
for Cmm papers and source.  Kaffe (an open source Java implementation)
also has custom allocators and collectors but I have forgotten the details.
-------------------
To unsubscribe, mail caml-list-request@inria.fr.  Archives: http://caml.inria.fr