The MM subsystem is trying to shrink struct page. This patchset introduces a memory descriptor for page table tracking - struct ptdesc.
This patchset introduces ptdesc, splits ptdesc from struct page, and converts many callers of page table constructor/destructors to use ptdescs. Ptdesc is a foundation to further standardize page tables, and eventually allow for dynamic allocation of page tables independent of struct page. However, the use of pages for page table tracking is quite deeply ingrained and varied across archictectures, so there is still a lot of work to be done before that can happen. This is rebased on next-20230531. v3: Got an Acked-by Fixed the arm64 compilation issue Rename some ptdesc utility functions to be pagetable_* instead Add some comments to functions describing their uses Vishal Moola (Oracle) (34): mm: Add PAGE_TYPE_OP folio functions s390: Use _pt_s390_gaddr for gmap address tracking s390: Use pt_frag_refcount for pagetables pgtable: Create struct ptdesc mm: add utility functions for ptdesc mm: Convert pmd_pgtable_page() to pmd_ptdesc() mm: Convert ptlock_alloc() to use ptdescs mm: Convert ptlock_ptr() to use ptdescs mm: Convert pmd_ptlock_init() to use ptdescs mm: Convert ptlock_init() to use ptdescs mm: Convert pmd_ptlock_free() to use ptdescs mm: Convert ptlock_free() to use ptdescs mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor} powerpc: Convert various functions to use ptdescs x86: Convert various functions to use ptdescs s390: Convert various gmap functions to use ptdescs s390: Convert various pgalloc functions to use ptdescs mm: Remove page table members from struct page pgalloc: Convert various functions to use ptdescs arm: Convert various functions to use ptdescs arm64: Convert various functions to use ptdescs csky: Convert __pte_free_tlb() to use ptdescs hexagon: Convert __pte_free_tlb() to use ptdescs loongarch: Convert various functions to use ptdescs m68k: Convert various functions to use ptdescs mips: Convert various functions to use ptdescs nios2: Convert __pte_free_tlb() to use ptdescs openrisc: Convert __pte_free_tlb() to use ptdescs riscv: Convert alloc_{pmd, pte}_late() to use ptdescs sh: Convert pte_free_tlb() to use ptdescs sparc64: Convert various functions to use ptdescs sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents um: Convert {pmd, pte}_free_tlb() to use ptdescs mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers Documentation/mm/split_page_table_lock.rst | 12 +- .../zh_CN/mm/split_page_table_lock.rst | 14 +- arch/arm/include/asm/tlb.h | 12 +- arch/arm/mm/mmu.c | 6 +- arch/arm64/include/asm/tlb.h | 14 +- arch/arm64/mm/mmu.c | 7 +- arch/csky/include/asm/pgalloc.h | 4 +- arch/hexagon/include/asm/pgalloc.h | 8 +- arch/loongarch/include/asm/pgalloc.h | 27 ++- arch/loongarch/mm/pgtable.c | 7 +- arch/m68k/include/asm/mcf_pgalloc.h | 41 ++-- arch/m68k/include/asm/sun3_pgalloc.h | 8 +- arch/m68k/mm/motorola.c | 4 +- arch/mips/include/asm/pgalloc.h | 31 +-- arch/mips/mm/pgtable.c | 7 +- arch/nios2/include/asm/pgalloc.h | 8 +- arch/openrisc/include/asm/pgalloc.h | 8 +- arch/powerpc/mm/book3s64/mmu_context.c | 10 +- arch/powerpc/mm/book3s64/pgtable.c | 32 +-- arch/powerpc/mm/pgtable-frag.c | 46 ++-- arch/riscv/include/asm/pgalloc.h | 8 +- arch/riscv/mm/init.c | 16 +- arch/s390/include/asm/pgalloc.h | 4 +- arch/s390/include/asm/tlb.h | 4 +- arch/s390/mm/gmap.c | 222 +++++++++++------- arch/s390/mm/pgalloc.c | 126 +++++----- arch/sh/include/asm/pgalloc.h | 9 +- arch/sparc/mm/init_64.c | 17 +- arch/sparc/mm/srmmu.c | 5 +- arch/um/include/asm/pgalloc.h | 18 +- arch/x86/mm/pgtable.c | 46 ++-- arch/x86/xen/mmu_pv.c | 2 +- include/asm-generic/pgalloc.h | 62 +++-- include/asm-generic/tlb.h | 11 + include/linux/mm.h | 155 ++++++++---- include/linux/mm_types.h | 14 -- include/linux/page-flags.h | 20 +- include/linux/pgtable.h | 61 +++++ mm/memory.c | 8 +- 39 files changed, 665 insertions(+), 449 deletions(-) -- 2.40.1