History log of /openbmc/linux/drivers/dax/kmem.c (Results 151 – 175 of 175)
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Revision tags: v5.2.4, v5.2.3
# 27988c96 24-Jul-2019 Mark Brown <broonie@kernel.org>

Merge tag 'v5.3-rc1' into regulator-5.3

Linus 5.3-rc1


# e27a2421 22-Jul-2019 Jonathan Corbet <corbet@lwn.net>

Merge tag 'v5.3-rc1' into docs-next

Pull in all of the massive docs changes from elsewhere.


# 03b0f2ce 22-Jul-2019 Maxime Ripard <maxime.ripard@bootlin.com>

Merge v5.3-rc1 into drm-misc-next

Noralf needs some SPI patches in 5.3 to merge some work on tinydrm.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>


# 3f98538c 22-Jul-2019 Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Merge tag 'v5.3-rc1' into patchwork

Linus 5.3-rc1

* tag 'v5.3-rc1': (12816 commits)
Linus 5.3-rc1
iommu/amd: fix a crash in iova_magazine_free_pfns
hexagon: switch to generic version of pte a

Merge tag 'v5.3-rc1' into patchwork

Linus 5.3-rc1

* tag 'v5.3-rc1': (12816 commits)
Linus 5.3-rc1
iommu/amd: fix a crash in iova_magazine_free_pfns
hexagon: switch to generic version of pte allocation
typo fix: it's d_make_root, not d_make_inode...
dt-bindings: pinctrl: stm32: Fix missing 'clocks' property in examples
dt-bindings: iio: ad7124: Fix dtc warnings in example
dt-bindings: iio: avia-hx711: Fix avdd-supply typo in example
dt-bindings: pinctrl: aspeed: Fix AST2500 example errors
dt-bindings: pinctrl: aspeed: Fix 'compatible' schema errors
dt-bindings: riscv: Limit cpus schema to only check RiscV 'cpu' nodes
dt-bindings: Ensure child nodes are of type 'object'
x86/entry/64: Prevent clobbering of saved CR2 value
smp: Warn on function calls from softirq context
KVM: x86: Add fixed counters to PMU filter
KVM: nVMX: do not use dangling shadow VMCS after guest reset
KVM: VMX: dump VMCS on failed entry
KVM: x86/vPMU: refine kvm_pmu err msg when event creation failed
KVM: s390: Use kvm_vcpu_wake_up in kvm_s390_vcpu_wakeup
KVM: Boost vCPUs that are delivering interrupts
KVM: selftests: Remove superfluous define from vmx.c
...

show more ...


# 4df4888b 22-Jul-2019 Takashi Iwai <tiwai@suse.de>

Merge branch 'topic/hda-acomp-base' into for-next

Pull the support for AMD / Nvidia HD-audio compmonent notification

Signed-off-by: Takashi Iwai <tiwai@suse.de>


Revision tags: v5.2.2
# 57a8ec38 17-Jul-2019 Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
"VM:
- z3fold fixes and enhancements by Henry Burns and Vitaly Wool

- more accurate reclaimed slab caches cal

Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
"VM:
- z3fold fixes and enhancements by Henry Burns and Vitaly Wool

- more accurate reclaimed slab caches calculations by Yafang Shao

- fix MAP_UNINITIALIZED UAPI symbol to not depend on config, by
Christoph Hellwig

- !CONFIG_MMU fixes by Christoph Hellwig

- new novmcoredd parameter to omit device dumps from vmcore, by
Kairui Song

- new test_meminit module for testing heap and pagealloc
initialization, by Alexander Potapenko

- ioremap improvements for huge mappings, by Anshuman Khandual

- generalize kprobe page fault handling, by Anshuman Khandual

- device-dax hotplug fixes and improvements, by Pavel Tatashin

- enable synchronous DAX fault on powerpc, by Aneesh Kumar K.V

- add pte_devmap() support for arm64, by Robin Murphy

- unify locked_vm accounting with a helper, by Daniel Jordan

- several misc fixes

core/lib:
- new typeof_member() macro including some users, by Alexey Dobriyan

- make BIT() and GENMASK() available in asm, by Masahiro Yamada

- changed LIST_POISON2 on x86_64 to 0xdead000000000122 for better
code generation, by Alexey Dobriyan

- rbtree code size optimizations, by Michel Lespinasse

- convert struct pid count to refcount_t, by Joel Fernandes

get_maintainer.pl:
- add --no-moderated switch to skip moderated ML's, by Joe Perches

misc:
- ptrace PTRACE_GET_SYSCALL_INFO interface

- coda updates

- gdb scripts, various"

[ Using merge message suggestion from Vlastimil Babka, with some editing - Linus ]

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (100 commits)
fs/select.c: use struct_size() in kmalloc()
mm: add account_locked_vm utility function
arm64: mm: implement pte_devmap support
mm: introduce ARCH_HAS_PTE_DEVMAP
mm: clean up is_device_*_page() definitions
mm/mmap: move common defines to mman-common.h
mm: move MAP_SYNC to asm-generic/mman-common.h
device-dax: "Hotremove" persistent memory that is used like normal RAM
mm/hotplug: make remove_memory() interface usable
device-dax: fix memory and resource leak if hotplug fails
include/linux/lz4.h: fix spelling and copy-paste errors in documentation
ipc/mqueue.c: only perform resource calculation if user valid
include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures
scripts/gdb: add helpers to find and list devices
scripts/gdb: add lx-genpd-summary command
drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
kernel/pid.c: convert struct pid count to refcount_t
drivers/rapidio/devices/rio_mport_cdev.c: NUL terminate some strings
select: shift restore_saved_sigmask_unless() into poll_select_copy_remaining()
select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR
...

show more ...


# 9f960da7 16-Jul-2019 Pavel Tatashin <pasha.tatashin@soleen.com>

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 machin

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>

show more ...


# 31e4ca92 16-Jul-2019 Pavel Tatashin <pasha.tatashin@soleen.com>

device-dax: fix memory and resource leak if hotplug fails

Patch series ""Hotremove" persistent memory", v6.

Recently, adding a persistent memory to be used like a regular RAM was
added to Linux. T

device-dax: fix memory and resource leak if hotplug fails

Patch series ""Hotremove" persistent memory", v6.

Recently, adding a persistent memory to be used like a regular RAM was
added to Linux. This work extends this functionality to also allow hot
removing persistent memory.

We (Microsoft) have an important use case for this functionality.

The requirement is for physical machines with small amount of RAM (~8G)
to be able to reboot in a very short period of time (<1s). Yet, there
is a userland state that is expensive to recreate (~2G).

The solution is to boot machines with 2G preserved for persistent
memory.

Copy the state, and hotadd the persistent memory so machine still has
all 8G available for runtime. Before reboot, offline and hotremove
device-dax 2G, copy the memory that is needed to be preserved to pmem0
device, and reboot.

The series of operations look like this:

1. After boot restore /dev/pmem0 to ramdisk to be consumed by apps.
and free ramdisk.
2. Convert raw pmem0 to devdax
ndctl create-namespace --mode devdax --map mem -e namespace0.0 -f
3. Hotadd to System RAM
echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind
echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id
echo online_movable > /sys/devices/system/memoryXXX/state
4. Before reboot hotremove device-dax memory from System RAM
echo offline > /sys/devices/system/memoryXXX/state
echo dax0.0 > /sys/bus/dax/drivers/kmem/unbind
5. Create raw pmem0 device
ndctl create-namespace --mode raw -e namespace0.0 -f
6. Copy the state that was stored by apps to ramdisk to pmem device
7. Do kexec reboot or reboot through firmware if firmware does not
zero memory in pmem0 region (These machines have only regular
volatile memory). So to have pmem0 device either memmap kernel
parameter is used, or devices nodes in dtb are specified.

This patch (of 3):

When add_memory() fails, the resource and the memory should be freed.

Link: http://lkml.kernel.org/r/20190517215438.6487-2-pasha.tatashin@soleen.com
Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...


Revision tags: v5.2.1
# 59747372 11-Jul-2019 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge branch 'next' into for-linus

Prepare input updates for 5.3 merge window.


Revision tags: v5.2, v5.1.16, v5.1.15, v5.1.14, v5.1.13, v5.1.12, v5.1.11, v5.1.10, v5.1.9, v5.1.8, v5.1.7, v5.1.6, v5.1.5, v5.1.4, v5.1.3, v5.1.2, v5.1.1
# 2a267e7c 10-May-2019 Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge tag 'v5.1' into next

Sync up with mainline to bring in the latest APIs.


Revision tags: v5.0.14
# 63b6f0b8 06-May-2019 Jiri Kosina <jkosina@suse.cz>

Merge branches 'for-5.1/upstream-fixes', 'for-5.2/core', 'for-5.2/ish', 'for-5.2/logitech', 'for-5.2/macally', 'for-5.2/picolcd', 'for-5.2/sensor' and 'for-5.2/u2fzero' into for-linus


Revision tags: v5.1, v5.0.13, v5.0.12, v5.0.11, v5.0.10, v5.0.9, v5.0.8
# 95d002e0 16-Apr-2019 Zhenyu Wang <zhenyuw@linux.intel.com>

Merge tag 'drm-intel-next-2019-04-04' into gvt-next

Merge back drm-intel-next for engine name definition refinement
and 54939ea0bd85 ("drm/i915: Switch to use HWS indices rather than addresses")
tha

Merge tag 'drm-intel-next-2019-04-04' into gvt-next

Merge back drm-intel-next for engine name definition refinement
and 54939ea0bd85 ("drm/i915: Switch to use HWS indices rather than addresses")
that would need gvt fixes to depend on.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

show more ...


# 3bfaf1f7 10-Apr-2019 Sean Paul <seanpaul@chromium.org>

Merge drm/drm-next into drm-misc-next

Finally have a reason for a backmerge other than "it's been a while"!

Backmerging drm-next to -misc-next to facilitate Rob Herring's work on
Panfrost.

Signed-

Merge drm/drm-next into drm-misc-next

Finally have a reason for a backmerge other than "it's been a while"!

Backmerging drm-next to -misc-next to facilitate Rob Herring's work on
Panfrost.

Signed-off-by: Sean Paul <seanpaul@chromium.org>

show more ...


Revision tags: v5.0.7, v5.0.6
# df768610 01-Apr-2019 Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Merge tag 'v5.1-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.1-rc3

Sync with upstream (which now contains fbdev-v5.1 changes) to
prepare a base

Merge tag 'v5.1-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.1-rc3

Sync with upstream (which now contains fbdev-v5.1 changes) to
prepare a base for fbdev-v5.2 changes.

show more ...


# 0e2f54f8 27-Mar-2019 Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge drm/drm-next into drm-intel-next-queued

This is needed to get the fourcc code merged without conflicts.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>


Revision tags: v5.0.5
# 9d7b7bfb 26-Mar-2019 James Morris <james.morris@microsoft.com>

Merge tag 'v5.1-rc2' into next-general

Merge to Linux 5.1-rc2 for subsystems to work with.


Revision tags: v5.0.4
# 249acb5f 19-Mar-2019 Mark Brown <broonie@kernel.org>

Merge tag 'v5.1-rc1' into spi-5.2

Linux 5.1-rc1


# c9e48084 19-Mar-2019 Mark Brown <broonie@kernel.org>

Merge tag 'v5.1-rc1' into regulator-5.2

Linux 5.1-rc1


Revision tags: v5.0.3
# 12747059 18-Mar-2019 Mark Brown <broonie@kernel.org>

Merge tag 'v5.1-rc1' into asoc-5.2

Linux 5.1-rc1


# c3bdd5e6 22-Apr-2019 Saeed Mahameed <saeedm@mellanox.com>

Merge tag 'v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into mlx5-next

Linux 5.1-rc1

We forgot to reset the branch last merge window thus mlx5-next is outdated
and stil

Merge tag 'v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into mlx5-next

Linux 5.1-rc1

We forgot to reset the branch last merge window thus mlx5-next is outdated
and still based on 5.0-rc2. This merge commit is needed to sync mlx5-next
branch with 5.1-rc1.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

show more ...


# 9b0dcd0e 11-Apr-2019 Takashi Iwai <tiwai@suse.de>

Merge tag 'asoc-fix-v5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.1

A few core fixes along with the driver specific ones, mainly fixing

Merge tag 'asoc-fix-v5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.1

A few core fixes along with the driver specific ones, mainly fixing
small issues that only affect x86 platforms for various reasons (their
unusual machine enumeration mechanisms mainly, plus a fix for error
handling in topology).

There's some of the driver fixes that look larger than they are, like
the hdmi-codec changes which resulted in an indentation change, and most
of the other large changes are for new drivers like the STM32 changes.

show more ...


# 356d71e0 27-Mar-2019 David S. Miller <davem@davemloft.net>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net


# 22d91ed3 18-Mar-2019 Mark Brown <broonie@kernel.org>

Merge tag 'v5.1-rc1' into asoc-5.1

Linux 5.1-rc1


# f67e3fb4 16-Mar-2019 Linus Torvalds <torvalds@linux-foundation.org>

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 ot

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

show more ...


Revision tags: v4.19.29, v5.0.2, v4.19.28, v5.0.1, v4.19.27, v5.0, v4.19.26
# c221c0b0 25-Feb-2019 Dave Hansen <dave.hansen@linux.intel.com>

device-dax: "Hotplug" persistent memory for use like normal RAM

This is intended for use with NVDIMMs that are physically persistent
(physically like flash) so that they can be used as a cost-effect

device-dax: "Hotplug" persistent memory for use like normal RAM

This is intended for use with NVDIMMs that are physically persistent
(physically like flash) so that they can be used as a cost-effective
RAM replacement. Intel Optane DC persistent memory is one
implementation of this kind of NVDIMM.

Currently, a persistent memory region is "owned" by a device driver,
either the "Direct DAX" or "Filesystem DAX" drivers. These drivers
allow applications to explicitly use persistent memory, generally
by being modified to use special, new libraries. (DIMM-based
persistent memory hardware/software is described in great detail
here: Documentation/nvdimm/nvdimm.txt).

However, this limits persistent memory use to applications which
*have* been modified. To make it more broadly usable, this driver
"hotplugs" memory into the kernel, to be managed and used just like
normal RAM would be.

To make this work, management software must remove the device from
being controlled by the "Device DAX" infrastructure:

echo dax0.0 > /sys/bus/dax/drivers/device_dax/unbind

and then tell the new driver that it can bind to the device:

echo dax0.0 > /sys/bus/dax/drivers/kmem/new_id

After this, there will be a number of new memory sections visible
in sysfs that can be onlined, or that may get onlined by existing
udev-initiated memory hotplug rules.

This rebinding procedure is currently a one-way trip. Once memory
is bound to "kmem", it's there permanently and can not be
unbound and assigned back to device_dax.

The kmem driver will never bind to a dax device unless the device
is *explicitly* bound to the driver. There are two reasons for
this: One, since it is a one-way trip, it can not be undone if
bound incorrectly. Two, the kmem driver destroys data on the
device. Think of if you had good data on a pmem device. It
would be catastrophic if you compile-in "kmem", but leave out
the "device_dax" driver. kmem would take over the device and
write volatile data all over your good data.

This inherits any existing NUMA information for the newly-added
memory from the persistent memory device that came from the
firmware. On Intel platforms, the firmware has guarantees that
require each socket's persistent memory to be in a separate
memory-only NUMA node. That means that this patch is not expected
to create NUMA nodes, but will simply hotplug memory into existing
nodes.

Because NUMA nodes are created, the existing NUMA APIs and tools
are sufficient to create policies for applications or memory areas
to have affinity for or an aversion to using this memory.

There is currently some metadata at the beginning of pmem regions.
The section-size memory hotplug restrictions, plus this small
reserved area can cause the "loss" of a section or two of capacity.
This should be fixable in follow-on patches. But, as a first step,
losing 256MB of memory (worst case) out of hundreds of gigabytes
is a good tradeoff vs. the required code to fix this up precisely.
This calculation is also the reason we export
memory_block_size_bytes().

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-nvdimm@lists.01.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
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: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

show more ...


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