From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Magenheimer <dan.magenheimer@oracle.com>
Subject: atomic counters larger than 24 bits?
Date: Thu, 26 Mar 2009 19:38:13 +0000 (GMT)
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In tmem, I have some counters that I need to keep coherent,
preferably without a lock, so I'm using atomic_inc/dec etc.
However the comments in include/asm-x86/atomic.h say repeatedly
that the "useful range of an atomic_t is only 24 bits".

First, are the comments true in the xen implementation?
(I don't see any code that restricts them to anything less
than "int".)  If they ARE limited to 24 bits, what's the
recommended approach for larger atomic operations... or
do I just need to always use a lock?

Thanks,
Dan