[PATCH 0/8] device-dax: sub-division support

From: Dan Williams
Date: Sun Dec 11 2016 - 01:33:01 EST

>From [PATCH 6/8] dax: sub-division support:

Device-DAX is a mechanism to establish mappings of performance / feature
differentiated memory with strict fault behavior guarantees. With
sub-division support a platform owner can provision sub-allocations of a
dax-region into separate devices. The provisioning mechanism follows the
same scheme as the libnvdimm sub-system in that a 'seed' device is
created at initialization time that can be resized from zero to become

Unlike the nvdimm sub-system there is no on media labelling scheme
associated with this partitioning. Provisioning decisions are ephemeral
/ not automatically restored after reboot. While the initial use case of
device-dax is persistent memory other uses case may be volatile, so the
device-dax core is unable to assume the underlying memory is pmem. The
task of recalling a partitioning scheme or permissions on the device(s)
is left to userspace.

For persistent allocations, naming, and permissions automatically
recalled by the kernel, use filesystem-DAX. For a userspace helper
library and utility for manipulating device-dax instances see libdaxctl
and the daxctl utility here: https://github.com/pmem/ndctl


Dan Williams (8):
dax: add region-available-size attribute
dax: add region 'id', 'size', and 'align' attributes
dax: register seed device
dax: use multi-order radix for resource lookup
dax: refactor locking out of size calculation routines
dax: sub-division support
dax: add / remove dax devices after provisioning
dax: add debug for region available_size

drivers/dax/Kconfig | 1
drivers/dax/dax.c | 747 ++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 698 insertions(+), 50 deletions(-)