linux/Documentation
Linus Torvalds f67e3fb489 device-dax for 5.1
* Replace the /sys/class/dax device model with /sys/bus/dax, and include
   a compat driver so distributions can opt-in to the new ABI.
 
 * Allow for an alternative driver for the device-dax address-range
 
 * Introduce the 'kmem' driver to hotplug / assign a device-dax
   address-range to the core-mm.
 
 * Arrange for the device-dax target-node to be onlined so that the newly
   added memory range can be uniquely referenced by numa apis.
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Merge tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull device-dax updates from Dan Williams:
 "New device-dax infrastructure to allow persistent memory and other
  "reserved" / performance differentiated memories, to be assigned to
  the core-mm as "System RAM".

  Some users want to use persistent memory as additional volatile
  memory. They are willing to cope with potential performance
  differences, for example between DRAM and 3D Xpoint, and want to use
  typical Linux memory management apis rather than a userspace memory
  allocator layered over an mmap() of a dax file. The administration
  model is to decide how much Persistent Memory (pmem) to use as System
  RAM, create a device-dax-mode namespace of that size, and then assign
  it to the core-mm. The rationale for device-dax is that it is a
  generic memory-mapping driver that can be layered over any "special
  purpose" memory, not just pmem. On subsequent boots udev rules can be
  used to restore the memory assignment.

  One implication of using pmem as RAM is that mlock() no longer keeps
  data off persistent media. For this reason it is recommended to enable
  NVDIMM Security (previously merged for 5.0) to encrypt pmem contents
  at rest. We considered making this recommendation an actively enforced
  requirement, but in the end decided to leave it as a distribution /
  administrator policy to allow for emulation and test environments that
  lack security capable NVDIMMs.

  Summary:

   - Replace the /sys/class/dax device model with /sys/bus/dax, and
     include a compat driver so distributions can opt-in to the new ABI.

   - Allow for an alternative driver for the device-dax address-range

   - Introduce the 'kmem' driver to hotplug / assign a device-dax
     address-range to the core-mm.

   - Arrange for the device-dax target-node to be onlined so that the
     newly added memory range can be uniquely referenced by numa apis"

NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because
we currently have special - and very annoying rules in the kernel about
accessing PMEM only with the "MC safe" accessors, because machine checks
inside the regular repeat string copy functions can be fatal in some
(not described) circumstances.

And apparently the PMEM modules can cause that a lot more than regular
RAM.  The argument is that this happens because PMEM doesn't necessarily
get scrubbed at boot like RAM does, but that is planned to be added for
the user space tooling.

Quoting Dan from another email:
 "The exposure can be reduced in the volatile-RAM case by scanning for
  and clearing errors before it is onlined as RAM. The userspace tooling
  for that can be in place before v5.1-final. There's also runtime
  notifications of errors via acpi_nfit_uc_error_notify() from
  background scrubbers on the DIMM devices. With that mechanism the
  kernel could proactively clear newly discovered poison in the volatile
  case, but that would be additional development more suitable for v5.2.

  I understand the concern, and the need to highlight this issue by
  tapping the brakes on feature development, but I don't see PMEM as RAM
  making the situation worse when the exposure is also there via DAX in
  the PMEM case. Volatile-RAM is arguably a safer use case since it's
  possible to repair pages where the persistent case needs active
  application coordination"

* tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: "Hotplug" persistent memory for use like normal RAM
  mm/resource: Let walk_system_ram_range() search child resources
  mm/memory-hotplug: Allow memory resources to be children
  mm/resource: Move HMM pr_debug() deeper into resource code
  mm/resource: Return real error codes from walk failures
  device-dax: Add a 'modalias' attribute to DAX 'bus' devices
  device-dax: Add a 'target_node' attribute
  device-dax: Auto-bind device after successful new_id
  acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node
  device-dax: Add /sys/class/dax backwards compatibility
  device-dax: Add support for a dax override driver
  device-dax: Move resource pinning+mapping into the common driver
  device-dax: Introduce bus + driver model
  device-dax: Start defining a dax bus model
  device-dax: Remove multi-resource infrastructure
  device-dax: Kill dax_region base
  device-dax: Kill dax_region ida
2019-03-16 13:05:32 -07:00
..
ABI device-dax for 5.1 2019-03-16 13:05:32 -07:00
accelerators
accounting psi: cgroup support 2018-10-26 16:26:32 -07:00
acpi ACPI: Documentation: Fix path for acpidbg tool 2019-03-07 11:28:33 +01:00
admin-guide for-5.1/block-post-20190315 2019-03-16 12:36:39 -07:00
aoe
arm ARM: 8833/1: Ensure that NEON code always compiles with Clang 2019-02-12 15:20:09 +00:00
arm64 arm64 updates for 5.1: 2019-03-10 10:17:23 -07:00
auxdisplay
backlight
block block: document usage of bio iterator helpers 2019-02-15 08:40:12 -07:00
blockdev zram: idle writeback fixes and cleanup 2019-01-08 17:15:10 -08:00
bpf docs/bpf: minor casing/punctuation fixes 2019-03-02 00:40:04 +01:00
bus-devices
cdrom Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
cgroup-v1 A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
cma
connector
console
core-api Merge branch 'akpm' (patches from Andrew) 2019-03-12 10:39:53 -07:00
cpu-freq Documentation: cpu-freq: Frequencies aren't always sorted 2018-11-07 13:29:04 +01:00
crypto crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
dev-tools Documentation/dev-tools: Use gcc version number instead svn revision number 2019-01-14 17:25:41 -07:00
device-mapper dm cache: add support for discard passdown to the origin device 2019-03-05 14:53:52 -05:00
devicetree fbdev changes for v5.1: 2019-03-15 14:22:59 -07:00
doc-guide docs: kernel-doc: typo "if ... if" -> "if ... is" 2019-02-17 15:38:47 -07:00
driver-api dmaengine updates for v5.1-rc1 2019-03-14 09:11:54 -07:00
driver-model Merge branches 'clk-optional', 'clk-devm-clkdev-register', 'clk-allwinner', 'clk-meson' and 'clk-renesas' into clk-next 2019-03-08 10:27:21 -08:00
early-userspace Correct gen_init_cpio tool's documentation 2018-11-25 12:25:53 -07:00
EDID Docs/EDID: Calculate CRC while building the code 2018-11-06 07:36:22 -07:00
extcon
fault-injection doc: fault-injection: fix macro name in example 2019-01-07 15:36:11 -07:00
fb fbdev: fbmem: convert CONFIG_FB_LOGO_CENTER into a cmd line option 2019-01-16 17:42:35 +01:00
features Documentation/features: Add csky kernel features 2019-01-07 22:22:16 +08:00
filesystems various tracing and debugging improvements, crediting fixes, some cleanup, and important fallocate fix (fixes three xfstests) and lock fix 2019-03-15 18:52:12 -07:00
firmware_class
fmc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
fpga
gpio Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
gpu Merge drm/drm-next into drm-misc-next 2019-02-11 10:35:35 +01:00
hid HID: doc: fix wrong data structure reference for UHID_OUTPUT 2018-12-18 14:55:22 +01:00
hwmon A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
i2c i2c: gpio: fault-injector: add 'inject_panic' injector 2019-02-23 10:34:08 +01:00
ia64
ide Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
iio
infiniband Documentation/infiniband: update from locked to pinned_vm 2019-02-07 12:56:23 -07:00
input doc: Change LXR references to elixir.bootlin.com 2019-02-01 16:05:03 -07:00
interconnect interconnect: Add generic on-chip interconnect API 2019-01-22 13:37:25 +01:00
ioctl seccomp: add a return code to trap to userspace 2018-12-11 16:28:41 -08:00
isdn Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
kbuild kbuild: remove cc-version macro 2019-03-04 22:34:59 +09:00
kdump kdump: Document kernel data exported in the vmcoreinfo note 2019-01-15 11:05:28 +01:00
kernel-hacking
laptops Documentation: fix lg-laptop.rst warnings 2019-02-11 08:27:47 -07:00
leds Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
lightnvm
livepatch livepatch: Remove signal sysfs attribute 2019-01-16 22:09:33 +01:00
locking Documentation/locking/lockdep: Drop last two chars of sample states 2019-03-04 12:55:18 -07:00
m68k Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
maintainer
md
media media: Documentation: fix several typos 2019-03-01 09:54:06 -05:00
memory-devices
mic
mips Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
misc-devices Documentation: add ibmvmc to toctree(index) and fix warnings 2019-01-14 08:37:17 -07:00
mmc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
mtd Documentation: mtd: remove stale pxa3xx NAND controller documentation 2018-09-04 23:37:38 +02:00
namespaces
netlabel Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
networking A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
nfc
nios2
nvdimm libnvdimm/security: Add documentation for nvdimm security support 2018-12-21 12:44:41 -08:00
nvmem Documentation: nvmem: document cell tables and lookup entries 2018-09-28 15:14:54 +02:00
openrisc
parisc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
PCI pci-v4.20-changes 2018-10-25 06:50:48 -07:00
pcmcia
perf Documentation: perf: Add documentation for ThunderX2 PMU uncore driver 2018-12-06 12:29:47 +00:00
phy
platform
power PM/EM: Document the Energy Model framework 2019-01-27 12:29:37 +01:00
powerpc powerpc/fadump: Reservationless firmware assisted dump 2018-12-21 11:32:49 +11:00
pps
process A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
pti
ptp
rapidio
RCU A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
riscv
s390 Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
scheduler sched/doc: Document Energy Aware Scheduling 2019-01-27 12:29:37 +01:00
scsi scsi: ufs-bsg: Allow reading descriptors 2019-02-27 09:00:02 -05:00
security doc: security: Add kern-doc for lsm_hooks.h 2019-02-22 08:54:09 -07:00
serial Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
sh sh: remove board_time_init() callback 2018-12-18 16:13:04 +01:00
sound ASoC: More changes for v5.1 2019-02-28 13:30:55 +01:00
sparc
sphinx
sphinx-static docs: improve readability for people with poorer eyesight 2018-10-07 09:16:50 -06:00
spi pxa2xx: replace spi_master with spi_controller 2019-01-23 10:59:56 +00:00
sysctl A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
target scsi: target/core: Remove the write_pending_status() callback function 2019-02-04 21:23:59 -05:00
thermal Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
timers Docs: Correct /proc/stat path 2019-02-22 08:50:17 -07:00
trace doc: trace: Fix documentation for uprobe_profile 2019-02-21 10:28:55 -05:00
translations A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
usb usb: core: add option of only authorizing internal devices 2019-02-22 09:27:55 +01:00
userspace-api x86/speculation: Add PR_SPEC_DISABLE_NOEXEC 2019-01-29 22:11:49 +01:00
virtual ARM: some cleanups, direct physical timer assignment, cache sanitization 2019-03-15 15:00:28 -07:00
vm docs: Use underscore not hyphen in label 2019-02-01 16:04:01 -07:00
w1 Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
watchdog Documentation/watchdog: Add documentation mlx-wdt driver 2019-03-02 15:28:20 +01:00
wimax
x86 x86/resctrl: Avoid confusion over the new X86_RESCTRL config 2019-02-02 10:34:52 +01:00
xilinx Documentation: xilinx: Add documentation for eemi APIs 2018-10-09 13:26:05 +02:00
xtensa xtensa: document boot parameter passing 2019-02-03 18:06:19 -08:00
.gitignore
atomic_bitops.txt
atomic_t.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
Changes
clearing-warn-once.txt
CodingStyle
conf.py This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt Documentation/DMA-API-HOWTO: update dma_mask sections 2019-02-20 07:29:47 -07:00
DMA-API.txt virtio: fixes, cleanups 2019-03-10 12:47:57 -07:00
DMA-attributes.txt
DMA-ISA-LPC.txt Documentation/DMA-ISA-LPC: fix an incorrect reference 2019-02-11 08:23:07 -07:00
docutils.conf
dontdiff kernel/configs: use .incbin directive to embed config_data.gz 2019-03-07 18:32:02 -08:00
efi-stub.txt efi_stub: update documentation on dtb= parameter 2018-09-09 14:46:44 -06:00
eisa.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst Documentation: add ibmvmc to toctree(index) and fix warnings 2019-01-14 08:37:17 -07:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-per-CPU-kthreads.txt
kobject.txt kref/kobject: Improve documentation 2018-12-06 13:57:03 +01:00
kprobes.txt
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
mailbox.txt
Makefile kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
memory-barriers.txt Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pnp.txt
preempt-locking.txt Documentation: preempt-locking: Use better example 2018-10-12 11:35:47 -06:00
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
speculation.txt
static-keys.txt static_keys.txt: Fix trivial spelling mistake 2019-02-06 16:44:16 -07:00
SubmittingPatches
svga.txt
switchtec.txt NTB: switchtec_ntb: Update switchtec documentation with prerequisites for NTB 2018-10-11 11:28:53 -05:00
sync_file.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
vfio-mediated-device.txt
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt