From: "Mike Rapoport (Microsoft)" <r...@kernel.org> Hi,
It's not uncommon that libnvdimm/dax/ndctl are used with normal volatile memory for a whole bunch of $reasons. Probably the most common usecase is to back VMs memory with fsdax/devdax, but there are others as well when there's a requirement to manage memory separately from the kernel. The existing mechanisms to expose normal ram as "persistent", such as memmap=x!y on x86 or dummy pmem-region device tree nodes on DT systems lack flexibility to dynamically partition a single region without rebooting the system. Also, to create several DAX devices with different properties it's necessary to repeat the memmap= command line option or add several pmem-region nodes to the DT. I propose a new driver that will create a DIMM device on E820_TYPE_PRAM/pmem-region and that will allow partitioning that device dynamically. The label area is kept in the end of that region and managed by the driver. Mike Rapoport (Microsoft) (1): nvdimm: allow exposing RAM carveouts as NVDIMM DIMM devices drivers/nvdimm/Kconfig | 15 +++ drivers/nvdimm/Makefile | 1 + drivers/nvdimm/ramdax.c | 279 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 295 insertions(+) create mode 100644 drivers/nvdimm/ramdax.c base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 -- 2.47.2
