From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-05-19T01:28:16+09:00
Subject: Re: ruby garbage collection

On Sun, May 18, 2003 at 11:30:48PM +0900, Simon Strandgaard wrote:
> On Mon, 19 May 2003 00:15:33 +0900, Gaffer wrote:
> 
> > an interesting aside, is there any benefit to using ruby's ALLOC etc.
> > functions over new/delete? i notice you dont, cheers
>  
> I don't know the difference:  new/delete  versus  rubys ALLOC.
> Can anyone shed some light on this ?

If you go through Ruby's allocation (ALLOC is equivalent to xmalloc
which is normally ruby_xmalloc) the information on how much memory has
been allocated is updated. If more than malloc_limit (a changing
threshold) bytes have been allocated a GC run is performed.

This means Ruby will not GC if you use new or malloc directly, but it
might start GC()ing in the middle of ALLOC.

You should bypass Ruby's ALLOC if you're pretty confident that no memory
will be regained in the GC pass.

void *
ruby_xmalloc(size)
    long size;
{
    void *mem;

    if (size < 0) {
        rb_raise(rb_eNoMemError, "negative allocation size (or too big)");
    }
    if (size == 0) size = 1;
    malloc_increase += size;

    if (malloc_increase > malloc_limit) {
        rb_gc();
    }
    RUBY_CRITICAL(mem = malloc(size));
    if (!mem) {
        rb_gc();
        RUBY_CRITICAL(mem = malloc(size));
        if (!mem) {
            rb_memerror();
        }
    }

    return mem;
}


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