Re: where is my memory?

[Johnny Billquist <bqt%softjar.se@localhost>]

der Mouse wrote:
> > > > total memory = 2047 MB
> > > > avail memory = 1999 MB
> > > total memory = 256 MB
> > > avail memory = 239 MB
> > Some graphics chips, especially on lower-end machines, use main
> > memory, thus making it unavailable to the CPU.
>
> It's not that simple.  I've seen this for a very long time, including
> on machines with no graphics chips at all, such as 4.3 on a VAX 750.
> Here's a live example; this is quoted from /var/run/dmesg.boot on a
> SPARCstation LX that's my desktop at one of my workplaces:
>
> total memory = 48688 KB
> avail memory = 41676 KB
>
> That's with a cg6 with its own private framebuffer RAM.

Well, for VAXen, the difference between total memory, and available
memory is:


***snip***

        format_bytes(pbuf, sizeof(pbuf), avail_end);
        printf("total memory = %s\n", pbuf);
        panicstr = NULL;
        mtpr(AST_NO, PR_ASTLVL);
        spl0();

#if VAX46 || VAX48 || VAX49 || VAX53 || VAXANY
        minaddr = 0;

        /*
         * Allocate a submap for physio.  This map effectively limits the
         * number of processes doing physio at any one time.
         */
        phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
                                   VM_PHYS_SIZE, 0, false, NULL);
#endif

        format_bytes(pbuf, sizeof(pbuf), ptoa(uvmexp.free));
        printf("avail memory = %s\n", pbuf);

***snip***

So, obviously a malloc for physio... :-)

Don't know about any other ports, but the code is there for the
inspection...

        Johnny