[RFC PATCH v2 00/20] Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64)

Christophe Leroy
2024-05-17T19:20:05Z

This is the continuation of the RFC v1 series "Reimplement huge pages
without hugepd on powerpc 8xx". It now get rid of hugepd completely
after handling also e500 and book3s/64

Unlike most architectures, powerpc 8xx HW requires a two-level
pagetable topology for all page sizes. So a leaf PMD-contig approach
is not feasible as such.

Possible sizes are 4k, 16k, 512k and 8M.

First level (PGD/PMD) covers 4M per entry. For 8M pages, two PMD entries
must point to a single entry level-2 page table. Until now that was
done using hugepd. This series changes it to use standard page tables
where the entry is replicated 1024 times on each of the two pagetables
refered by the two associated PMD entries for that 8M page.

At the moment it has to look into each helper to know if the
hugepage ptep is a PTE or a PMD in order to know it is a 8M page or
a lower size. I hope this can me handled by core-mm in the future.

For e500 and book3s/64 there are less constraints because it is not
tied to the HW assisted tablewalk like on 8xx, so it is easier to use
leaf PMDs (and PUDs).

On e500 the supported page sizes are 4M, 16M, 64M, 256M and 1G. All at
PMD level on e500/32 and mix of PMD and PUD for e500/64. We encode page
size with 4 available bits in PTE entries. On e300/32 PGD entries size
is increases to 64 bits in order to allow leaf-PMD entries because PTE
are 64 bits on e500.

On book3s/64 only the hash-4k mode is concerned. It supports 16M pages
as cont-PMD and 16G pages as cont-PUD. In other modes (radix-4k, radix-6k
and hash-64k) the sizes match with PMD and PUD sizes so that's just leaf
entries.

Christophe Leroy (20):
mm: Provide pagesize to pmd_populate()
mm: Provide page size to pte_alloc_huge()
mm: Provide pmd to pte_leaf_size()
mm: Provide mm_struct and address to huge_ptep_get()
powerpc/mm: Allow hugepages without hugepd
powerpc/8xx: Fix size given to set_huge_pte_at()
powerpc/8xx: Rework support for 8M pages using contiguous PTE entries
powerpc/8xx: Simplify struct mmu_psize_def
powerpc/mm: Remove _PAGE_PSIZE
powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries
powerpc/mm: Complement huge_pte_alloc() for all non HUGEPD setups
powerpc/64e: Remove unneeded #ifdef CONFIG_PPC_E500
powerpc/64e: Clean up impossible setups
powerpc/e500: Remove enc field from struct mmu_psize_def
powerpc/85xx: Switch to 64 bits PGD
powerpc/e500: Encode hugepage size in PTE bits
powerpc/e500: Use contiguous PMD instead of hugepd
powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD
powerpc/mm: Remove hugepd leftovers
mm: Remove CONFIG_ARCH_HAS_HUGEPD

arch/arm/include/asm/hugetlb-3level.h | 2 +-
arch/arm64/include/asm/hugetlb.h | 2 +-
arch/arm64/include/asm/pgtable.h | 2 +-
arch/arm64/mm/hugetlbpage.c | 4 +-
arch/parisc/mm/hugetlbpage.c | 2 +-
arch/powerpc/Kconfig | 1 -
arch/powerpc/include/asm/book3s/32/pgalloc.h | 2 -
arch/powerpc/include/asm/book3s/64/hash-4k.h | 15 -
arch/powerpc/include/asm/book3s/64/hash.h | 38 +-
arch/powerpc/include/asm/book3s/64/hugetlb.h | 38 --
.../include/asm/book3s/64/pgtable-4k.h | 34 --
.../include/asm/book3s/64/pgtable-64k.h | 20 -
arch/powerpc/include/asm/hugetlb.h | 26 +-
.../include/asm/nohash/32/hugetlb-8xx.h | 58 +--
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 9 +-
arch/powerpc/include/asm/nohash/32/pgalloc.h | 2 +
arch/powerpc/include/asm/nohash/32/pte-40x.h | 3 -
arch/powerpc/include/asm/nohash/32/pte-44x.h | 3 -
arch/powerpc/include/asm/nohash/32/pte-85xx.h | 3 -
arch/powerpc/include/asm/nohash/32/pte-8xx.h | 64 ++-
.../powerpc/include/asm/nohash/hugetlb-e500.h | 36 +-
arch/powerpc/include/asm/nohash/mmu-e500.h | 4 -
arch/powerpc/include/asm/nohash/pgalloc.h | 2 -
arch/powerpc/include/asm/nohash/pgtable.h | 45 +-
arch/powerpc/include/asm/nohash/pte-e500.h | 22 +-
arch/powerpc/include/asm/page.h | 32 --
arch/powerpc/include/asm/pgtable-be-types.h | 10 -
arch/powerpc/include/asm/pgtable-types.h | 13 +-
arch/powerpc/include/asm/pgtable.h | 3 +
arch/powerpc/kernel/head_85xx.S | 33 +-
arch/powerpc/kernel/head_8xx.S | 10 +-
arch/powerpc/mm/book3s64/hash_utils.c | 11 +-
arch/powerpc/mm/book3s64/pgtable.c | 12 -
arch/powerpc/mm/hugetlbpage.c | 450 ++----------------
arch/powerpc/mm/init-common.c | 8 +-
arch/powerpc/mm/kasan/8xx.c | 15 +-
arch/powerpc/mm/nohash/8xx.c | 46 +-
arch/powerpc/mm/nohash/book3e_pgtable.c | 4 +-
arch/powerpc/mm/nohash/tlb.c | 172 ++-----
arch/powerpc/mm/nohash/tlb_low_64e.S | 257 ++--------
arch/powerpc/mm/pgtable.c | 94 ++--
arch/powerpc/mm/pgtable_32.c | 2 +-
arch/riscv/include/asm/hugetlb.h | 2 +-
arch/riscv/include/asm/pgtable.h | 2 +-
arch/riscv/mm/hugetlbpage.c | 4 +-
arch/s390/include/asm/hugetlb.h | 2 +-
arch/s390/mm/hugetlbpage.c | 2 +-
arch/sh/mm/hugetlbpage.c | 2 +-
arch/sparc/include/asm/pgtable_64.h | 2 +-
arch/sparc/mm/hugetlbpage.c | 4 +-
fs/hugetlbfs/inode.c | 2 +-
fs/proc/task_mmu.c | 8 +-
fs/userfaultfd.c | 2 +-
include/asm-generic/hugetlb.h | 2 +-
include/linux/hugetlb.h | 10 +-
include/linux/mm.h | 12 +-
include/linux/pgtable.h | 2 +-
include/linux/swapops.h | 2 +-
kernel/events/core.c | 2 +-
mm/Kconfig | 10 -
mm/damon/vaddr.c | 6 +-
mm/filemap.c | 2 +-
mm/gup.c | 105 +---
mm/hmm.c | 2 +-
mm/hugetlb.c | 46 +-
mm/internal.h | 2 +-
mm/memory-failure.c | 2 +-
mm/memory.c | 19 +-
mm/mempolicy.c | 2 +-
mm/migrate.c | 4 +-
mm/mincore.c | 2 +-
mm/pagewalk.c | 57 +--
mm/pgalloc-track.h | 2 +-
mm/userfaultfd.c | 6 +-
74 files changed, 494 insertions(+), 1444 deletions(-)

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2.44.0