linux/drivers/dax
Pavel Tatashin 9f960da72b device-dax: "Hotremove" persistent memory that is used like normal RAM
It is now allowed to use persistent memory like a regular RAM, but
currently there is no way to remove this memory until machine is
rebooted.

This work expands the functionality to also allows hotremoving
previously hotplugged persistent memory, and recover the device for use
for other purposes.

To hotremove persistent memory, the management software must first
offline all memory blocks of dax region, and than unbind it from
device-dax/kmem driver.  So, operations should look like this:

  echo offline > /sys/devices/system/memory/memoryN/state
  ...
  echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind

Note: if unbind is done without offlining memory beforehand, it won't be
possible to do dax0.0 hotremove, and dax's memory is going to be part of
System RAM until reboot.

Link: http://lkml.kernel.org/r/20190517215438.6487-4-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-16 19:23:24 -07:00
..
pmem memremap: move dev_pagemap callbacks into a separate structure 2019-07-02 14:32:44 -03:00
bus.c device-dax: Add a 'modalias' attribute to DAX 'bus' devices 2019-02-27 21:03:48 -08:00
bus.h acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node 2019-01-06 21:41:57 -08:00
dax-private.h device-dax: "Hotremove" persistent memory that is used like normal RAM 2019-07-16 19:23:24 -07:00
device.c device-dax: use the dev_pagemap internal refcount 2019-07-02 14:32:44 -03:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kmem.c device-dax: "Hotremove" persistent memory that is used like normal RAM 2019-07-16 19:23:24 -07:00
Makefile device-dax: "Hotplug" persistent memory for use like normal RAM 2019-02-28 10:41:23 -08:00
super.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00