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.comSigned-off-by: NPavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: NDavid 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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Showing
想要评论请 注册 或 登录