ext4 and XFS file systems now support DAX

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ext4 and XFS file systems now support DAX
Starting with Red Hat Enterprise Linux 7.3, Direct Access (DAX) provides, as a Technology Preview, 
a means for an application to directly map persistent memory into its address space. 
To use DAX, a system must have some form of persistent memory available, 
usually in the form of one or more Non-Volatile Dual In-line Memory Modules (NVDIMMs), 
and a file system that supports DAX must be created on the NVDIMM(s). 
Also, the file system must be mounted with the dax mount option. 
Then, an mmap of a file on the dax-mounted file system results in a direct mapping of storage into the application's address space. (BZ#1274459)