On Wed, May 18, 2016 at 01:56:16PM -0700, Dan Williams wrote: > 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 > ranges. > > This commit is limited to the base device driver infrastructure to > associate a dax device with pmem range. > > Cc: Jeff Moyer <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Dave Hansen <[email protected]> > Cc: Ross Zwisler <[email protected]> > Signed-off-by: Dan Williams <[email protected]>
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