linux/init
Kiryl Shutsemau (Meta) c6f11553c0 mm: decouple protnone helpers from CONFIG_NUMA_BALANCING
Patch series "userfaultfd: working set tracking for VM guest memory", v10.

This series adds userfaultfd support for tracking the working set of VM
guest memory, so a VMM can identify hot pages and reclaim cold ones to
tiered or remote storage.


This patch (of 15):

pte_protnone() and pmd_protnone() detect present-but-inaccessible page
table entries.  This capability is useful beyond NUMA balancing -- for
example, userfaultfd working set tracking uses protnone PTEs to track page
access without unmapping pages.

Introduce CONFIG_ARCH_HAS_PTE_PROTNONE to decouple the protnone PTE
infrastructure from CONFIG_NUMA_BALANCING.  The six architectures that
support protnone PTEs (x86_64, arm64, powerpc, s390, riscv, loongarch) now
select this option, and CONFIG_NUMA_BALANCING depends on it.

No functional change -- the same set of architectures continues to have
working protnone support, but the infrastructure is now available
independently of NUMA balancing.

Link: https://lore.kernel.org/20260708111417.173443-1-kirill@shutemov.name
Link: https://lore.kernel.org/20260708111417.173443-2-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: James Houghton <jthoughton@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-04 19:18:36 -07:00
..
.gitignore kbuild: build init/built-in.a just once 2022-09-29 04:40:15 +09:00
.kunitconfig initramfs_test: kunit tests for initramfs unpacking 2025-03-08 12:13:04 +01:00
calibrate.c calibrate: update header inclusion 2025-11-27 14:24:45 -08:00
do_mounts_initrd.c init: remove /proc/sys/kernel/real-root-dev 2026-01-12 17:22:27 +01:00
do_mounts_rd.c initrd: remove deprecated code path (linuxrc) 2026-01-12 17:22:22 +01:00
do_mounts.c init: do_mounts: use kmalloc() for allocations of temporary buffers 2026-05-22 12:12:20 +02:00
do_mounts.h fs: use nullfs unconditionally as the real rootfs 2026-01-14 11:23:39 +01:00
init_task.c Scheduler updates for v7.2: 2026-06-15 14:50:18 +05:30
initramfs_internal.h init: add initramfs_internal.h 2025-03-04 09:52:36 +01:00
initramfs_test.c init/initramfs_test: wait_for_initramfs() before running 2026-05-27 15:11:02 +02:00
initramfs.c initramfs: Refactor to use hex2bin() instead of custom approach 2026-05-21 09:32:46 +02:00
Kconfig mm: decouple protnone helpers from CONFIG_NUMA_BALANCING 2026-08-04 19:18:36 -07:00
main.c bootconfig: move xbc_snprint_cmdline() to lib/bootconfig.c 2026-05-12 09:44:31 +09:00
Makefile initramfs_test: kunit tests for initramfs unpacking 2025-03-08 12:13:04 +01:00
noinitramfs.c
version-timestamp.c ns: drop custom reference count initialization for initial namespaces 2025-11-11 10:01:32 +01:00
version.c init/version.c: Replace strlcpy with strscpy 2023-09-22 09:50:56 -07:00