Re: [Xen-devel] atomic counters larger than 24 bits?

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Dan Magenheimer, le Thu 26 Mar 2009 19:38:13 +0000, a écrit :
> 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".

IIRC the historical reason for this is that some Linux architectures
weren't providing more.  The x86 implementation does support signed 32
bits. I believe the ia64 implementation does too.

Samuel

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