lwn.git/arch/x86/mm/pat, branch docs-fixes

x86/mm: Revert INVLPGB optimization for set_memory code

2026-04-24T13:42:48+00:00

tl;dr: Revert an INVLPGB optimization that did not properly handle discontiguous virtual addresses. Full story: I got a report from some graphics (i915) folks that bisected a regression in their test suite to 86e6815b316e ("x86/mm: Change cpa_flush() to call flush_kernel_range() directly"). There was a bit of flip-flopping on the exact bisect, but the code here does seem wrong to me. The i915 folks were calling set_pages_array_wc(), so using the CPA_PAGES_ARRAY mode. Basically, the 'struct cpa_data' can wrap up all kinds of page table changes. Some of these are virtually contiguous, but some are very much not which is one reason why there are ->vaddr and ->pages arrays. 86e6815b316e made the mistake of assuming that the virtual addresses in the cpa_data are always contiguous. It got things right when neither CPA_ARRAY/CPA_PAGES_ARRAY is used, but theoretically wrong when either of those is used. In the i915 case, it probably failed to flush some WB TLB entries and install WC ones, leaving some data in the caches and not flushing it out to where the device could see it. That eventually caused graphics problems. Revert the INVLPGB optimization. It can be reintroduced later, but it will need to be a bit careful about the array modes. Fixes: 86e6815b316ec ("x86/mm: Change cpa_flush() to call flush_kernel_range()") Reported-by: Cui, Ling Signed-off-by: Dave Hansen Signed-off-by: Ingo Molnar Reviewed-by: Rick Edgecombe Reviewed-by: Thomas Hellström Link: https://patch.msgid.link/20260421151909.6B3281C6@davehans-spike.ostc.intel.com

x86/mm/pat: Convert split_large_page() to use ptdescs

2026-03-04T18:08:54+00:00

Use the ptdesc APIs for all page table allocation and free sites to allow their separate allocation from struct page in the future. Update split_large_page() to allocate a ptdesc instead of allocating a page for use as a page table. Signed-off-by: Vishal Moola (Oracle) Signed-off-by: Dave Hansen Acked-by: Mike Rapoport (Microsoft) Link: https://patch.msgid.link/20260303194828.1406905-5-vishal.moola@gmail.com

x86/mm/pat: Convert populate_pgd() to use page table apis

2026-03-04T18:08:54+00:00

Use the ptdesc APIs for all page table allocation and free sites to allow their separate allocation from struct page in the future. Convert the remaining get_zeroed_page() calls to the generic page table APIs, as they already use ptdescs. Pass through init_mm since these are kernel page tables, as both functions require it to identify kernel page tables. Because the generic implementations do not use the second argument, pass a placeholder to avoid reimplementing them or risking breakage on other architectures. It is not obvious whether these pages are freed. Regardless, convert the remaining free paths as needed, noting that the only other possible free paths have already been converted and that a frozen page table test kernel has not reported any issues. Signed-off-by: Vishal Moola (Oracle) Signed-off-by: Dave Hansen Acked-by: Mike Rapoport (Microsoft) Link: https://patch.msgid.link/20260303194828.1406905-4-vishal.moola@gmail.com

x86/mm/pat: Convert pmd code to use page table apis

2026-03-04T18:08:54+00:00

Use the ptdesc APIs for all page table allocation and free sites to allow their separate allocation from struct page in the future. Convert the PMD allocation and free sites to use the generic page table APIs, as they already use ptdescs. Pass through init_mm since these are kernel page tables, as pmd_alloc_one() requires it to identify kernel page tables. Because the generic implementation does not use the second argument, pass a placeholder to avoid reimplementing it or risking breakage on other architectures. Signed-off-by: Vishal Moola (Oracle) Signed-off-by: Dave Hansen Acked-by: Mike Rapoport (Microsoft) Link: https://patch.msgid.link/20260303194828.1406905-3-vishal.moola@gmail.com

x86/mm/pat: Convert pte code to use page table apis

2026-03-04T18:08:54+00:00

Use the ptdesc APIs for all page table allocation and free sites to allow their separate allocation from struct page in the future. Convert the PTE allocation and free sites to use the generic page table APIs, as they already use ptdescs. Pass through init_mm since these are kernel page tables; otherwise, pte_alloc_one_kernel() becomes a no-op. Signed-off-by: Vishal Moola (Oracle) Signed-off-by: Dave Hansen Acked-by: Mike Rapoport (Microsoft) Link: https://patch.msgid.link/20260303194828.1406905-2-vishal.moola@gmail.com

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

x86/crash: Use set_memory_p() instead of __set_memory_prot()

2026-01-13T14:28:59+00:00

set_memory_p() is available to use outside of its compilation unit since: 030ad7af9437 ("x86/mm: Regularize set_memory_p() parameters and make non-static"). There is no use for __set_memory_prot() anymore so drop it too. [ bp: Massage commit message. ] Signed-off-by: Coiby Xu Signed-off-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20260106095100.656292-1-coxu@redhat.com

Merge tag 'soc-drivers-6.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

2025-12-06T01:47:59+00:00

Pull more SoC driver updates from Arnd Bergmann: "These updates came a little late, or were based on a later 6.18-rc tag than the others: - A new driver for cache management on cxl devices with memory shared in a coherent cluster. This is part of the drivers/cache/ tree, but unlike the other drivers that back the dma-mapping interfaces, this one is needed only during CPU hotplug. - A shared branch for reset controllers using swnode infrastructure - Added support for new SoC variants in the Amlogic soc_device identification - Minor updates in Freescale, Microchip, Samsung, and Apple SoC drivers" * tag 'soc-drivers-6.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (24 commits) soc: samsung: exynos-pmu: fix device leak on regmap lookup soc: samsung: exynos-pmu: Fix structure initialization soc: fsl: qbman: use kmalloc_array() instead of kmalloc() soc: fsl: qbman: add WQ_PERCPU to alloc_workqueue users MAINTAINERS: Update email address for Christophe Leroy MAINTAINERS: refer to intended file in STANDALONE CACHE CONTROLLER DRIVERS cache: Support cache maintenance for HiSilicon SoC Hydra Home Agent cache: Make top level Kconfig menu a boolean dependent on RISCV MAINTAINERS: Add Jonathan Cameron to drivers/cache and add lib/cache_maint.c + header arm64: Select GENERIC_CPU_CACHE_MAINTENANCE lib: Support ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION soc: amlogic: meson-gx-socinfo: add new SoCs id dt-bindings: arm: amlogic: meson-gx-ao-secure: support more SoCs memregion: Support fine grained invalidate by cpu_cache_invalidate_memregion() memregion: Drop unused IORES_DESC_* parameter from cpu_cache_invalidate_memregion() dt-bindings: cache: sifive,ccache0: add a pic64gx compatible MAINTAINERS: rename Microchip RISC-V entry MAINTAINERS: add new soc drivers to Microchip RISC-V entry soc: microchip: add mfd drivers for two syscon regions on PolarFire SoC dt-bindings: soc: microchip: document the simple-mfd syscon on PolarFire SoC ...

Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-05T21:52:43+00:00

Pull MM updates from Andrew Morton: "__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki) Rework the vmalloc() code to support non-blocking allocations (GFP_ATOIC, GFP_NOWAIT) "ksm: fix exec/fork inheritance" (xu xin) Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not inherited across fork/exec "mm/zswap: misc cleanup of code and documentations" (SeongJae Park) Some light maintenance work on the zswap code "mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira) Enhance the /sys/kernel/debug/page_owner debug feature by adding unique identifiers to differentiate the various stack traces so that userspace monitoring tools can better match stack traces over time "mm/page_alloc: pcp->batch cleanups" (Joshua Hahn) Minor alterations to the page allocator's per-cpu-pages feature "Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra) Address a scalability issue in userfaultfd's UFFDIO_MOVE operation "kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov) "drivers/base/node: fold node register and unregister functions" (Donet Tom) Clean up the NUMA node handling code a little "mm: some optimizations for prot numa" (Kefeng Wang) Cleanups and small optimizations to the NUMA allocation hinting code "mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn) Address long lock hold times at boot on large machines. These were causing (harmless) softlockup warnings "optimize the logic for handling dirty file folios during reclaim" (Baolin Wang) Remove some now-unnecessary work from page reclaim "mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park) Enhance the DAMOS auto-tuning feature "mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan) Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace configuration "expand mmap_prepare functionality, port more users" (Lorenzo Stoakes) Enhance the new(ish) file_operations.mmap_prepare() method and port additional callsites from the old ->mmap() over to ->mmap_prepare() "Fix stale IOTLB entries for kernel address space" (Lu Baolu) Fix a bug (and possible security issue on non-x86) in the IOMMU code. In some situations the IOMMU could be left hanging onto a stale kernel pagetable entry "mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang) Clean up and optimize the folio splitting code "mm, swap: misc cleanup and bugfix" (Kairui Song) Some cleanups and a minor fix in the swap discard code "mm/damon: misc documentation fixups" (SeongJae Park) "mm/damon: support pin-point targets removal" (SeongJae Park) Permit userspace to remove a specific monitoring target in the middle of the current targets list "mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo) A couple of cleanups related to mm header file inclusion "mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He) improve the selection of swap devices for NUMA machines "mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista) Change the memory block labels from macros to enums so they will appear in kernel debug info "ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes) Address an inefficiency when KSM unmerges an address range "mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park) Fix leaks and unhandled malloc() failures in DAMON userspace unit tests "some cleanups for pageout()" (Baolin Wang) Clean up a couple of minor things in the page scanner's writeback-for-eviction code "mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu) Move hugetlb's sysfs/sysctl handling code into a new file "introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes) Make the VMA guard regions available in /proc/pid/smaps and improves the mergeability of guarded VMAs "mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes) Reduce mmap lock contention for callers performing VMA guard region operations "vma_start_write_killable" (Matthew Wilcox) Start work on permitting applications to be killed when they are waiting on a read_lock on the VMA lock "mm/damon/tests: add more tests for online parameters commit" (SeongJae Park) Add additional userspace testing of DAMON's "commit" feature "mm/damon: misc cleanups" (SeongJae Park) "make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes) Address the possible loss of a VMA's VM_SOFTDIRTY flag when that VMA is merged with another "mm: support device-private THP" (Balbir Singh) Introduce support for Transparent Huge Page (THP) migration in zone device-private memory "Optimize folio split in memory failure" (Zi Yan) "mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang) Some more cleanups in the folio splitting code "mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes) Clean up our handling of pagetable leaf entries by introducing the concept of 'software leaf entries', of type softleaf_t "reparent the THP split queue" (Muchun Song) Reparent the THP split queue to its parent memcg. This is in preparation for addressing the long-standing "dying memcg" problem, wherein dead memcg's linger for too long, consuming memory resources "unify PMD scan results and remove redundant cleanup" (Wei Yang) A little cleanup in the hugepage collapse code "zram: introduce writeback bio batching" (Sergey Senozhatsky) Improve zram writeback efficiency by introducing batched bio writeback support "memcg: cleanup the memcg stats interfaces" (Shakeel Butt) Clean up our handling of the interrupt safety of some memcg stats "make vmalloc gfp flags usage more apparent" (Vishal Moola) Clean up vmalloc's handling of incoming GFP flags "mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang) Teach soft dirty and userfaultfd write protect tracking to use RISC-V's Svrsw60t59b extension "mm: swap: small fixes and comment cleanups" (Youngjun Park) Fix a small bug and clean up some of the swap code "initial work on making VMA flags a bitmap" (Lorenzo Stoakes) Start work on converting the vma struct's flags to a bitmap, so we stop running out of them, especially on 32-bit "mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park) Address a possible bug in the swap discard code and clean things up a little [ This merge also reverts commit ebb9aeb980e5 ("vfio/nvgrace-gpu: register device memory for poison handling") because it looks broken to me, I've asked for clarification - Linus ] * tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm: fix vma_start_write_killable() signal handling mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate mm/swapfile: fix list iteration when next node is removed during discard fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling mm/kfence: add reboot notifier to disable KFENCE on shutdown memcg: remove inc/dec_lruvec_kmem_state helpers selftests/mm/uffd: initialize char variable to Null mm: fix DEBUG_RODATA_TEST indentation in Kconfig mm: introduce VMA flags bitmap type tools/testing/vma: eliminate dependency on vma->__vm_flags mm: simplify and rename mm flags function for clarity mm: declare VMA flags by bit zram: fix a spelling mistake mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity mm/vmscan: skip increasing kswapd_failures when reclaim was boosted pagemap: update BUDDY flag documentation mm: swap: remove scan_swap_map_slots() references from comments mm: swap: change swap_alloc_slow() to void mm, swap: remove redundant comment for read_swap_cache_async mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational ...