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Date: Fri, 8 Jun 2001 18:16:12 +0400
From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Cc: Tom Vier <tmv5@home.com>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
        linux-kernel@vger.kernel.org
Subject: Re: [patch] Re: Linux 2.4.5-ac6
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In-Reply-To: <Pine.GSO.3.96.1010607193120.16852B-100000@delta.ds2.pg.gda.pl>; from macro@ds2.pg.gda.pl on Thu, Jun 07, 2001 at 08:28:04PM +0200
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On Thu, Jun 07, 2001 at 08:28:04PM +0200, Maciej W. Rozycki wrote:
>  DU seems to map as low as possible, it would seem.

Yes, I've just checked, starting at 64K...

>  Maybe we could just
> do the same for OSF/1 binaries by setting TASK_UNMAPPED_BASE
> appropriately? 

No. I've changed in load_aout_binary() set_personality(PER_LINUX) to
set_personality(PER_LINUX_32BIT), and now I have another error.
You will laugh, but...

$ netscape
665:/usr/lib/netscape/netscape-communicator: : Fatal Error: mmap available address is not larger than requested

This happens after
mmap(0x7fdc8000, 40960, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000

And note, this is the message from loader, not from netscape itself.
So I think my second patch is an easiest solution for now.
Look, compared with the code in Linus' tree:
- it doesn't add any overhead in general case (addr == 0);
- if the specified address is too high and we can't find a free
  area above it, we just continue search from TASK_UNMAPPED_BASE
  as usual; 
- if address is too low, extra cost is only compare and taken branch.
I think it's clean enough.

Ivan.