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| author | Dan Williams <dan.j.williams@intel.com> | 2019-11-06 17:43:43 -0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-11-07 15:45:00 +0100 |
| commit | a6c7f4c6aea5f4ca6056b06cec7ebd79f8c23e33 (patch) | |
| tree | c942e9a1b25e2cf4b47a233ef22e4badebcd86c7 /drivers/dax/Kconfig | |
| parent | 460370ab20b6cc174256e46e192adf01e730faf6 (diff) | |
| download | lwn-a6c7f4c6aea5f4ca6056b06cec7ebd79f8c23e33.tar.gz lwn-a6c7f4c6aea5f4ca6056b06cec7ebd79f8c23e33.zip | |
device-dax: Add a driver for "hmem" devices
Platform firmware like EFI/ACPI may publish "hmem" platform devices.
Such a device is a performance differentiated memory range likely
reserved for an application specific use case. The driver gives access
to 100% of the capacity via a device-dax mmap instance by default.
However, if over-subscription and other kernel memory management is
desired the resulting dax device can be assigned to the core-mm via the
kmem driver.
This consumes "hmem" devices the producer of "hmem" devices is saved for
a follow-on patch so that it can reference the new CONFIG_DEV_DAX_HMEM
symbol to gate performing the enumeration work.
Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/dax/Kconfig')
| -rw-r--r-- | drivers/dax/Kconfig | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig index f33c73e4af41..3b6c06f07326 100644 --- a/drivers/dax/Kconfig +++ b/drivers/dax/Kconfig @@ -32,19 +32,36 @@ config DEV_DAX_PMEM Say M if unsure +config DEV_DAX_HMEM + tristate "HMEM DAX: direct access to 'specific purpose' memory" + depends on EFI_SOFT_RESERVE + default DEV_DAX + help + EFI 2.8 platforms, and others, may advertise 'specific purpose' + memory. For example, a high bandwidth memory pool. The + indication from platform firmware is meant to reserve the + memory from typical usage by default. This driver creates + device-dax instances for these memory ranges, and that also + enables the possibility to assign them to the DEV_DAX_KMEM + driver to override the reservation and add them to kernel + "System RAM" pool. + + Say M if unsure. + config DEV_DAX_KMEM tristate "KMEM DAX: volatile-use of persistent memory" default DEV_DAX depends on DEV_DAX depends on MEMORY_HOTPLUG # for add_memory() and friends help - Support access to persistent memory as if it were RAM. This - allows easier use of persistent memory by unmodified - applications. + Support access to persistent, or other performance + differentiated memory as if it were System RAM. This allows + easier use of persistent memory by unmodified applications, or + adds core kernel memory services to heterogeneous memory types + (HMEM) marked "reserved" by platform firmware. To use this feature, a DAX device must be unbound from the - device_dax driver (PMEM DAX) and bound to this kmem driver - on each boot. + device_dax driver and bound to this kmem driver on each boot. Say N if unsure. |