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Date:      Sat, 21 Aug 1999 11:10:14 -0700
From:      Jason Thorpe <thorpej@nas.nasa.gov>
To:        Wes Peters <wes@softweyr.com>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: mmap mapped segment length 
Message-ID:  <199908211810.LAA13809@lestat.nas.nasa.gov>

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On Sat, 21 Aug 1999 02:10:47 -0600 
 Wes Peters <wes@softweyr.com> wrote:

 > I discovered to my dismay today that the length field in the mmap call is
 > a size_t, not an off_t.  I was attempting to process a large (~50 MByte) file
 > and found I was only processing the first 4 MBytes of it.

...first of all, I assume you mean GByte, not MByte.

The type of the "len" argument is specified by multiple standards.  You could
change size_t to a 64-bit quantity, but then you have:

	(1) A serious ABI incompatibility issue with the rest of the x86
	    world.

	(2) You'd have to go to 64-bit arithmetic everywhere in the VM code
	    which could seriously impact performance.

 > Is this intentional, or just an artifact of the implementation?  Is there any
 > reason NOT to change this to an off_t?

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>



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