Re: GCC 4.8 out of memory

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Tue, Jun 02, 2015 at 04:16:48PM +0200, Frank Wille wrote:
> On Mon, 1 Jun 2015 20:28:13 +0200
> Michael van Elst <mlelstv%serpens.de@localhost> wrote:
> 
> > > Ok, I used most of that, but 32 MB for the text segment seems too much.
> > > I chose 16 MB.
> > 
> > It is just a limit. The only constraint is that the text+data+stack
> > address space must be handled by pmap which is limited to 512MB.
> 
> Wasn't that 224MB for 040/060?

that was apparently fixed:

revision 1.41
date: 2010-12-28 19:31:05 +0100;  author: mhitch;  state: Exp;  lines: +2 -3;
branches:  1.41.2;  1.41.4;
Raise address of user stack to the highest safe (for 68040 mmu) address,
which increases available user address space by 256MB.  One file in
pkgsrc/lang/php53 was too large for the amiga.  Also remove an old
presumably outdated comment.


> > largest binary I've seen so far is cc1plus with about 7MB.
> 
> That's just the text segment of cc1 and cc1plus. But I wonder what happens
> with the dynamically linked text segments from all the shared objects? Do
> we have to add their sizes?

There is one place where MAXTSIZ is used, this is the check_exec()
function that validates among other things the size of the text
segment in an executable. Shared objects are mapped later by
the runtime linker, and there is no runtime limit for text size.



> > The bumped VM_KERNEL_PT_PAGES are necessary for up to 2GB RAM.
> 
> In my understanding the current 224MB pmap limit makes that useless.
> And from the comment in vmparam.h I though this is just the initial
> value, which will be dynamically extended?

It is the number of pages that is used for the initial MMU table
before the tables are expanded dynamically. After all, you need
some memory to allocate additional MMU pages from.

The size depends on the amount of physical RAM you have. 8 Pages
is probably good enough for any real world Amiga now, but it isn't
enough to handle 2GB. With netbsd-6 I needed 9 pages for 2GB,
but netbsd-7 allocates more in early stages, so it's now 10.
I have tried to use more than 2GB without success, probably
a signed/unsigned error somewhere.


Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."