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authorDan Williams <dan.j.williams@intel.com>2016-05-18 09:15:08 -0700
committerDan Williams <dan.j.williams@intel.com>2016-05-20 22:02:53 -0700
commitab68f26221366f92611650e8470e6a926801c7d4 (patch)
treea43178bfd901b84c6b65a6b293f03bc4c9d04076 /drivers/dax/Kconfig
parent6cf9c5babd980ec1959e0dd45e3036474c6a294f (diff)
/dev/dax, pmem: direct access to persistent memory
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 <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: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax/Kconfig')
-rw-r--r--drivers/dax/Kconfig25
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
new file mode 100644
index 000000000000..86ffbaa891ad
--- /dev/null
+++ b/drivers/dax/Kconfig
@@ -0,0 +1,25 @@
+menuconfig DEV_DAX
+ tristate "DAX: direct access to differentiated memory"
+ default m if NVDIMM_DAX
+ help
+ Support raw access to differentiated (persistence, bandwidth,
+ latency...) memory via an mmap(2) capable character
+ device. Platform firmware or a device driver may identify a
+ platform memory resource that is differentiated from the
+ baseline memory pool. Mappings of a /dev/daxX.Y device impose
+ restrictions that make the mapping behavior deterministic.
+
+if DEV_DAX
+
+config DEV_DAX_PMEM
+ tristate "PMEM DAX: direct access to persistent memory"
+ depends on NVDIMM_DAX
+ default DEV_DAX
+ help
+ Support raw access to persistent memory. Note that this
+ driver consumes memory ranges allocated and exported by the
+ libnvdimm sub-system.
+
+ Say Y if unsure
+
+endif