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Re: A sick idea - mmapped file output

To: gcc at gcc dot gnu dot org
Subject: Re: A sick idea - mmapped file output
From: Russ Allbery <rra at stanford dot edu>
Date: 03 Nov 2000 18:31:10 -0800
Organization: The Eyrie
References: <20001102214053.G322@wolery.stanford.edu><200011040202.SAA04519@penguin.transmeta.com>

Linus Torvalds <torvalds@transmeta.com> writes:

>  - a number of (especially older) systems will not guarantee 100%
>    synchronization with mmap/read.  At the very least you should add a
>    msync() call, but I suspect you might still find systems where there
>    are separate caches for mmap and for "regular IO", and you might have
>    aliasing and resulting non-reproducible behaviour.

Our experience with INN was that even calling msync after writing to the
mmap'd pages didn't always cause everything to show up to a subsequent
read on platforms that didn't have a unified cache.

-- 
Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>

References:
- A sick idea - mmapped file output
  - From: Zack Weinberg
- Re: A sick idea - mmapped file output
  - From: Linus Torvalds

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