| Thomas Gleixner | ec8f24b | 2019-05-19 13:07:45 +0100 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0-only |
| Dan Williams | 7b6be84 | 2017-04-11 09:49:49 -0700 | [diff] [blame] | 2 | menuconfig DAX |
| Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame] | 3 | tristate "DAX: direct access to differentiated memory" |
| Dan Williams | 956a4cd | 2017-04-07 16:42:08 -0700 | [diff] [blame] | 4 | select SRCU |
| Dan Williams | 7b6be84 | 2017-04-11 09:49:49 -0700 | [diff] [blame] | 5 | default m if NVDIMM_DAX |
| 6 | |
| 7 | if DAX |
| 8 | |
| 9 | config DEV_DAX |
| 10 | tristate "Device DAX: direct access mapping device" |
| 11 | depends on TRANSPARENT_HUGEPAGE |
| Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame] | 12 | help |
| 13 | Support raw access to differentiated (persistence, bandwidth, |
| 14 | latency...) memory via an mmap(2) capable character |
| 15 | device. Platform firmware or a device driver may identify a |
| 16 | platform memory resource that is differentiated from the |
| 17 | baseline memory pool. Mappings of a /dev/daxX.Y device impose |
| 18 | restrictions that make the mapping behavior deterministic. |
| 19 | |
| Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame] | 20 | config DEV_DAX_PMEM |
| 21 | tristate "PMEM DAX: direct access to persistent memory" |
| Mike Galbraith | 74d71a0 | 2017-05-06 06:14:43 +0200 | [diff] [blame] | 22 | depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX |
| Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame] | 23 | default DEV_DAX |
| 24 | help |
| 25 | Support raw access to persistent memory. Note that this |
| 26 | driver consumes memory ranges allocated and exported by the |
| 27 | libnvdimm sub-system. |
| 28 | |
| Dan Williams | 730926c | 2017-07-16 13:51:53 -0700 | [diff] [blame] | 29 | Say M if unsure |
| 30 | |
| Dan Williams | a6c7f4c | 2019-11-06 17:43:43 -0800 | [diff] [blame] | 31 | config DEV_DAX_HMEM |
| 32 | tristate "HMEM DAX: direct access to 'specific purpose' memory" |
| 33 | depends on EFI_SOFT_RESERVE |
| Dan Williams | 5ccac54 | 2020-10-13 16:49:28 -0700 | [diff] [blame] | 34 | select NUMA_KEEP_MEMINFO if (NUMA && X86) |
| Dan Williams | a6c7f4c | 2019-11-06 17:43:43 -0800 | [diff] [blame] | 35 | default DEV_DAX |
| 36 | help |
| 37 | EFI 2.8 platforms, and others, may advertise 'specific purpose' |
| 38 | memory. For example, a high bandwidth memory pool. The |
| 39 | indication from platform firmware is meant to reserve the |
| 40 | memory from typical usage by default. This driver creates |
| 41 | device-dax instances for these memory ranges, and that also |
| 42 | enables the possibility to assign them to the DEV_DAX_KMEM |
| 43 | driver to override the reservation and add them to kernel |
| 44 | "System RAM" pool. |
| 45 | |
| 46 | Say M if unsure. |
| 47 | |
| Dan Williams | c01044c | 2020-10-13 16:49:13 -0700 | [diff] [blame] | 48 | config DEV_DAX_HMEM_DEVICES |
| 49 | depends on DEV_DAX_HMEM && DAX=y |
| 50 | def_bool y |
| 51 | |
| Dave Hansen | c221c0b | 2019-02-25 10:57:40 -0800 | [diff] [blame] | 52 | config DEV_DAX_KMEM |
| 53 | tristate "KMEM DAX: volatile-use of persistent memory" |
| 54 | default DEV_DAX |
| 55 | depends on DEV_DAX |
| 56 | depends on MEMORY_HOTPLUG # for add_memory() and friends |
| 57 | help |
| Dan Williams | a6c7f4c | 2019-11-06 17:43:43 -0800 | [diff] [blame] | 58 | Support access to persistent, or other performance |
| 59 | differentiated memory as if it were System RAM. This allows |
| 60 | easier use of persistent memory by unmodified applications, or |
| 61 | adds core kernel memory services to heterogeneous memory types |
| 62 | (HMEM) marked "reserved" by platform firmware. |
| Dave Hansen | c221c0b | 2019-02-25 10:57:40 -0800 | [diff] [blame] | 63 | |
| 64 | To use this feature, a DAX device must be unbound from the |
| Dan Williams | a6c7f4c | 2019-11-06 17:43:43 -0800 | [diff] [blame] | 65 | device_dax driver and bound to this kmem driver on each boot. |
| Dave Hansen | c221c0b | 2019-02-25 10:57:40 -0800 | [diff] [blame] | 66 | |
| 67 | Say N if unsure. |
| 68 | |
| Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame] | 69 | endif |