• Dan Williams's avatar
    /dev/dax, pmem: direct access to persistent memory · ab68f262
    Dan Williams authored
    Device DAX is the device-centric analogue of Filesystem DAX
    (CONFIG_FS_DAX).  It allows memory ranges to be allocated and mapped
    without need of an intervening file system.  Device DAX is strict,
    precise and predictable.  Specifically this interface:
    1/ Guarantees fault granularity with respect to a given page size (pte,
    pmd, or pud) set at configuration time.
    2/ Enforces deterministic behavior by being strict about what fault
    scenarios are supported.
    For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE
    support device-dax guarantees that a mapping always behaves/performs the
    same once established.  It is the "what you see is what you get" access
    mechanism to differentiated memory vs filesystem DAX which has
    filesystem specific implementation semantics.
    Persistent memory is the first target, but the mechanism is also
    targeted for exclusive allocations of performance differentiated memory
    This commit is limited to the base device driver infrastructure to
    associate a dax device with pmem range.
    Cc: Jeff Moyer <jmoyer@redhat.com>
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
    Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Makefile 4.92 KB