linux/mm
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.
 -----BEGIN PGP SIGNATURE-----
 
 iQIcBAABAgAGBQJchWpGAAoJEB7SkWpmfYgCJk8P/0Q1DINszUDO/vKjJ09cDs9P
 Jw3it6GBIL50rDOu9QdcprSpwYDD0h1mLAV/m6oa3bVO+p4uWGvnxaxRx2HN2c/v
 vhZFtUDpHlqR63vzWMNVKRprYixCRJDUr6xQhhCcE3ak/ELN6w7LWfikKVWv15UL
 MfR96IQU38f+xRda/zSXnL9606Dvkvu/inEHj84lRcHIwj3sQAUalrE8bR3O32gZ
 bDg/l5kzT49o8ZXUo/TegvRSSSZpJmOl2DD0RW+ax5q3NI2bOXFrVDUKBKxf/hcQ
 E/V9i57TrqQx0GqRhnU7rN/v53cFZGGs31TEEIB/xs3bzCnADxwXcjL5b5K005J6
 vJjBA2ODBewHFK3uVx46Hy1iV4eCtZWj4QrMnrjdSrjXOfbF5GTbWOhPFgoq7TWf
 S7VqFEf3I2gDPaMq4o8Ej1kLH4HMYeor2NSOZjyvGn87rSZ3ZIQguwbaNIVl+itz
 gdDt0ZOU0BgOBkV+rZIeZDaGdloWCHcDPL15CkZaOZyzdWhfEZ7dod6ad+9udilU
 EUPH62RgzXZtfm5zpebYyjNVLbb9pLZ0nT+UypyGR6zqWx1SqU3mXi63NFXPco+x
 XA9j//edPeI6NHg2CXLEh8DLuCg3dG1zWRJANkiF+niBwyCR8CHtGWAoY6soXbKe
 2UrXGcIfXxyJ8V9v8v4q
 =hfa3
 -----END PGP SIGNATURE-----

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
..
kasan treewide: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
Kconfig ksm: replace jhash2 with xxhash 2018-12-28 12:11:46 -08:00
Kconfig.debug mm/page_owner: move config option to mm/Kconfig.debug 2019-03-05 21:07:18 -08:00
Makefile mm: remove nobootmem 2018-10-31 08:54:16 -07:00
backing-dev.c writeback: synchronize sync(2) against cgroup writeback membership switches 2019-01-22 14:39:38 -07:00
balloon_compaction.c
cleancache.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
cma.c memblock: emphasize that memblock_alloc_range() returns a physical address 2019-03-12 10:04:01 -07:00
cma.h
cma_debug.c mm/cma_debug.c: remove static scoped cma_debugfs_root 2019-03-05 21:07:20 -08:00
compaction.c mm/compaction: pass pgdat to too_many_isolated() instead of zone 2019-03-05 21:07:21 -08:00
debug.c 5.1 Merge Window Pull Request 2019-03-09 15:53:03 -08:00
debug_page_ref.c
dmapool.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
early_ioremap.c
fadvise.c vfs: implement readahead(2) using POSIX_FADV_WILLNEED 2018-08-30 20:01:32 +02:00
failslab.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
filemap.c filemap: add a comment about FAULT_FLAG_RETRY_NOWAIT behavior 2019-03-15 11:26:07 -07:00
frame_vector.c
frontswap.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
gup.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-07 17:43:58 -08:00
gup_benchmark.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
highmem.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
hmm.c mm/hmm: convert to use vm_fault_t 2019-03-12 10:04:00 -07:00
huge_memory.c mm/huge_memory.c: fix "orig_pud" set but not used 2019-03-05 21:07:21 -08:00
hugetlb.c mm: update get_user_pages_longterm to migrate pages allocated from CMA region 2019-03-05 21:07:19 -08:00
hugetlb_cgroup.c mm: rename page_counter's count/limit into usage/max 2018-06-07 17:34:35 -07:00
hwpoison-inject.c
init-mm.c mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids 2018-07-17 09:35:30 +02:00
internal.h mm, compaction: capture a page under direct compaction 2019-03-05 21:07:17 -08:00
interval_tree.c
khugepaged.c mm: memcontrol: expose THP events on a per-memcg basis 2019-03-05 21:07:19 -08:00
kmemleak-test.c
kmemleak.c kmemleak: account for tagged pointers when calculating pointer range 2019-02-21 09:01:00 -08:00
ksm.c mm: ksm: do not block on page lock when searching stable tree 2019-03-05 21:07:19 -08:00
list_lru.c numa: make "nr_node_ids" unsigned int 2019-03-05 21:07:19 -08:00
maccess.c Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" 2019-02-25 09:10:51 -08:00
madvise.c mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
memblock.c mm: memblock: update comments and kernel-doc 2019-03-12 10:04:02 -07:00
memcontrol.c mm/memcontrol.c: fix bad line in comment 2019-03-05 21:07:21 -08:00
memfd.c mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd 2019-03-05 21:07:19 -08:00
memory-failure.c mm: hwpoison: fix thp split handing in soft_offline_in_use_page() 2019-03-05 21:07:13 -08:00
memory.c mm/memory.c: do_fault: avoid usage of stale vm_area_struct 2019-03-05 21:07:21 -08:00
memory_hotplug.c device-dax for 5.1 2019-03-16 13:05:32 -07:00
mempolicy.c mm, mempolicy: fix uninit memory access 2019-03-05 21:07:18 -08:00
mempool.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
memtest.c
migrate.c mm/migrate.c: cleanup expected_page_refs() 2019-03-05 21:07:20 -08:00
mincore.c Revert "Change mincore() to count "mapped" pages rather than "cached" pages" 2019-01-24 09:04:37 +13:00
mlock.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
mm_init.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
mmap.c mm: fix some typos in mm directory 2019-03-05 21:07:18 -08:00
mmu_context.c
mmu_gather.c mm: Replace call_rcu_sched() with call_rcu() 2018-11-27 09:21:46 -08:00
mmu_notifier.c mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
mmzone.c
mprotect.c mm: update ptep_modify_prot_commit to take old pte value as arg 2019-03-05 21:07:18 -08:00
mremap.c mm,mremap: bail out earlier in mremap_to under map pressure 2019-03-05 21:07:21 -08:00
msync.c
nommu.c mm/gup: cache dev_pagemap while pinning pages 2018-10-26 16:38:15 -07:00
oom_kill.c mm,oom: don't kill global init via memory.oom.group 2019-03-05 21:07:19 -08:00
page-writeback.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
page_alloc.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
page_counter.c memcg: introduce memory.min 2018-06-07 17:34:36 -07:00
page_ext.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
page_idle.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
page_io.c mm/page_io.c: fix polled swap page in 2019-01-04 13:13:48 -08:00
page_isolation.c mm: only report isolation failures when offlining memory 2018-12-28 12:11:46 -08:00
page_owner.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
page_poison.c page_poison: play nicely with KASAN 2019-03-05 21:07:13 -08:00
page_vma_mapped.c mm/rmap: map_pte() was not handling private ZONE_DEVICE page properly 2018-10-31 08:54:11 -07:00
pagewalk.c
percpu-internal.h
percpu-km.c percpu: km: no need to consider pcpu_group_offsets[0] 2019-02-26 13:47:58 -08:00
percpu-stats.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
percpu-vm.c
percpu.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
pgtable-generic.c x86/mm: Page size aware flush_tlb_mm_range() 2018-10-09 16:51:11 +02:00
process_vm_access.c
quicklist.c
readahead.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
rmap.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
rodata_test.c
shmem.c mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd 2019-03-05 21:07:19 -08:00
slab.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
slab.h memcg: localize memcg_kmem_enabled() check 2019-03-05 21:07:15 -08:00
slab_common.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
slob.c slab: __GFP_ZERO is incompatible with a constructor 2018-06-07 17:34:34 -07:00
slub.c numa: make "nr_node_ids" unsigned int 2019-03-05 21:07:19 -08:00
sparse-vmemmap.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
sparse.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
swap.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
swap_cgroup.c
swap_slots.c mm, swap, get_swap_pages: use entry_size instead of cluster in parameter 2018-08-22 10:52:44 -07:00
swap_state.c mm: swap: add comment for swap_vma_readahead 2019-03-05 21:07:16 -08:00
swapfile.c mm/swapfile.c: use struct_size() in kvzalloc() 2019-03-05 21:07:21 -08:00
truncate.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
usercopy.c mm/usercopy.c: no check page span for stack objects 2019-01-08 17:15:11 -08:00
userfaultfd.c hugetlbfs: revert "use i_mmap_rwsem for more pmd sharing synchronization" 2019-01-08 17:15:11 -08:00
util.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
vmacache.c mm: get rid of vmacache_flush_all() entirely 2018-09-13 15:18:04 -10:00
vmalloc.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
vmpressure.c mm/vmpressure.c: convert to use match_string() helper 2018-06-07 17:34:36 -07:00
vmscan.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
vmstat.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
workingset.c mm/workingset: remove unused @mapping argument in workingset_eviction() 2019-03-05 21:07:21 -08:00
z3fold.c z3fold: fix possible reclaim races 2018-11-18 10:15:09 -08:00
zbud.c
zpool.c
zsmalloc.c mm/zsmalloc.c: fix fall-through annotation 2018-10-26 16:26:35 -07:00
zswap.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00