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From: Christoph Lameter <cl@linux.com>
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To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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        Mark Hairgrove <mhairgrove@nvidia.com>,
        Geoffrey Gerfin <ggerfin@nvidia.com>,
        John McKenna <jmckenna@nvidia.com>, akpm@linux-foundation.org
Subject: Re: Interacting with coherent memory on external devices
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On Thu, 23 Apr 2015, Paul E. McKenney wrote:

>
> DAX
>
> 	DAX is a mechanism for providing direct-memory access to
> 	high-speed non-volatile (AKA "persistent") memory.  Good
> 	introductions to DAX may be found in the following LWN
> 	articles:

DAX is a mechanism to access memory not managed by the kernel and is the
successor to XIP. It just happens to be needed for persistent memory.
Fundamentally any driver can provide an MMAPPed interface to allow access
to a devices memory.