linux.git/mm/memory_hotplug.c, branch v6.14-rc2

mm: add build-time option for hotplug memory default online type

2025-01-26T04:22:21+00:00

Memory hotplug presently auto-onlines memory into a zone the kernel deems
appropriate if CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y.

The memhp_default_state boot param enables runtime config, but it's not
possible to do this at build-time.

Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with
CONFIG_MHP_DEFAULT_ONLINE_TYPE_* choices that sync with the boot param.

Selections:
  CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE
    => mhp_default_online_type = "offline"
       Memory will not be onlined automatically.

  CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO
    => mhp_default_online_type = "online"
       Memory will be onlined automatically in a zone deemed.
       appropriate by the kernel.

  CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL
    => mhp_default_online_type = "online_kernel"
       Memory will be onlined automatically.
       The zone may allow kernel data (e.g. ZONE_NORMAL).

  CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE
    => mhp_default_online_type = "online_movable"
       Memory will be onlined automatically.
       The zone will be ZONE_MOVABLE.

Default to CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE to match the existing
default CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n behavior.

Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y should use
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO.

[gourry@gourry.net: update KConfig comments]
  Link: https://lkml.kernel.org/r/20241226182918.648799-1-gourry@gourry.net
Link: https://lkml.kernel.org/r/20241220210709.300066-1-gourry@gourry.net
Signed-off-by: Gregory Price 
Acked-by: David Hildenbrand 
Cc: Greg Kroah-Hartman 
Cc: Huacai Chen 
Cc: Jonathan Corbet 
Cc: Oscar Salvador 
Cc: "Rafael J. Wysocki" 
Cc: WANG Xuerui 
Signed-off-by: Andrew Morton

mm/memory_hotplug: don't use __GFP_HARDWALL when migrating pages via memory offlining

2025-01-14T06:40:53+00:00

We'll migrate pages allocated by other context; respecting the cpuset of
the memory offlining context when allocating a migration target does not
make sense.

Drop the __GFP_HARDWALL by using GFP_KERNEL.

Note that in an ideal world, migration code could figure out the cpuset
of the original context and take that into consideration.

Link: https://lkml.kernel.org/r/20241205090508.2095225-3-david@redhat.com
Signed-off-by: David Hildenbrand 
Suggested-by: Vlastimil Babka 
Reviewed-by: Vlastimil Babka 
Acked-by: Oscar Salvador 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

mm/page_isolation: don't pass gfp flags to start_isolate_page_range()

2025-01-14T06:40:44+00:00

The parameter is unused, so let's stop passing it.

Link: https://lkml.kernel.org/r/20241203094732.200195-3-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Zi Yan 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Oscar Salvador 
Reviewed-by: Vishal Moola (Oracle) 
Cc: Christophe Leroy 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Naveen N Rao 
Cc: Nicholas Piggin 
Signed-off-by: Andrew Morton

mm/memory_hotplug: move debug_pagealloc_map_pages() into online_pages_range()

2025-01-14T06:40:44+00:00

In the near future, we want to have a single way to handover PageOffline
pages to the buddy, whereby they could have:

(a) Never been exposed to the buddy before: kept PageOffline when onlining
    the memory block.
(b) Been allocated from the buddy, for example using
    alloc_contig_range() to then be set PageOffline,

Let's start by making generic_online_page()->__free_pages_core() less
special compared to ordinary page freeing (e.g., free_contig_range()),
and perform the debug_pagealloc_map_pages() call unconditionally, even
when the online callback might decide to keep the pages offline.

All pages are already initialized with PageOffline, so nobody touches them
either way.

Link: https://lkml.kernel.org/r/20241203102050.223318-1-david@redhat.com
Signed-off-by: David Hildenbrand 
Acked-by: Oscar Salvador 
Signed-off-by: Andrew Morton

kaslr: rename physmem_end and PHYSMEM_END to direct_map_physmem_end

2024-11-07T04:11:11+00:00

For clarity.  It's increasingly hard to reason about the code, when KASLR
is moving around the boundaries.  In this case where KASLR is randomizing
the location of the kernel image within physical memory, the maximum
number of address bits for physical memory has not changed.

What has changed is the ending address of memory that is allowed to be
directly mapped by the kernel.

Let's name the variable, and the associated macro accordingly.

Also, enhance the comment above the direct_map_physmem_end definition,
to further clarify how this all works.

Link: https://lkml.kernel.org/r/20241009025024.89813-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard 
Reviewed-by: Pankaj Gupta 
Acked-by: David Hildenbrand 
Acked-by: Will Deacon 
Reviewed-by: Mike Rapoport (Microsoft) 
Cc: Thomas Gleixner 
Cc: Alistair Popple 
Cc: Jordan Niethe 
Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-09-21T14:29:05+00:00

Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:

- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.

- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.

- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.

- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.

- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.

- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as

$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0

which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".

- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".

- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.

- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.

- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.

- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.

- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.

- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.

- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().

- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.

- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,

- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.

- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.

- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.

- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.

- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.

- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.

- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.

- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.

- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.

- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.

- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().

- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!

- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.

- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.

- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.

- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.

- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.

- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.

- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.

- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.

- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.

- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.

- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.

- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.

- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.

- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.

- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.

- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.

- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.

- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.

- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.

- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...

mm: memory_hotplug: unify Huge/LRU/non-LRU movable folio isolation

2024-09-04T04:15:59+00:00

Use the isolate_folio_to_list() to unify hugetlb/LRU/non-LRU folio
isolation, which cleanup code a bit and save a few calls to
compound_head().

[wangkefeng.wang@huawei.com: various fixes]
  Link: https://lkml.kernel.org/r/20240829150500.2599549-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240827114728.3212578-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Miaohe Lin 
Cc: Dan Carpenter 
Cc: David Hildenbrand 
Cc: Jonathan Cameron 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Signed-off-by: Andrew Morton

mm: memory_hotplug: check hwpoisoned page firstly in do_migrate_range()

2024-09-04T04:15:59+00:00

Commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to
be offlined") don't handle the hugetlb pages, the endless loop still occur
if offline a hwpoison hugetlb page, luckly, after the commit e591ef7d96d6
("mm, hwpoison,hugetlb,memory_hotplug: hotremove memory section with
hwpoisoned hugepage"), the HPageMigratable of hugetlb page will be
cleared, and the hwpoison hugetlb page will be skipped in
scan_movable_pages(), so the endless loop issue is fixed.

However if the HPageMigratable() check passed(without reference and lock),
the hugetlb page may be hwpoisoned, it won't cause issue since the
hwpoisoned page will be handled correctly in the next movable pages scan
loop, and it will be isolated in do_migrate_range() but fails to migrate. 
In order to avoid the unnecessary isolation and unify all hwpoisoned page
handling, let's unconditionally check hwpoison firstly, and if it is a
hwpoisoned hugetlb page, try to unmap it as the catch all safety net like
normal page does.

Link: https://lkml.kernel.org/r/20240827114728.3212578-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Acked-by: David Hildenbrand 
Reviewed-by: Miaohe Lin 
Cc: Dan Carpenter 
Cc: Jonathan Cameron 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Signed-off-by: Andrew Morton

mm: memory_hotplug: remove head variable in do_migrate_range()

2024-09-04T04:15:58+00:00

Patch series "mm: memory_hotplug: improve do_migrate_range()", v3.

Unify hwpoisoned page handling and isolation of HugeTLB/LRU/non-LRU
movable page, also convert to use folios in do_migrate_range().


This patch (of 5):

Directly use a folio for HugeTLB and THP when calculate the next pfn, then
remove unused head variable.

Link: https://lkml.kernel.org/r/20240827114728.3212578-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240827114728.3212578-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Miaohe Lin 
Acked-by: David Hildenbrand 
Cc: Dan Carpenter 
Cc: Jonathan Cameron 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Signed-off-by: Andrew Morton

mm/memory_hotplug: get rid of __ref

2024-09-02T03:25:56+00:00

After commit 73db3abdca58 ("init/modpost: conditionally check section
mismatch to __meminit*"), we can get rid of __ref annotations.

Link: https://lkml.kernel.org/r/20240726010157.6177-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang 
Acked-by: David Hildenbrand 
Cc: Masahiro Yamada 
Cc: Oscar Salvador 
Signed-off-by: Andrew Morton