Re: [PATCH v2 00/13] mm: remove __ARCH_HAS_5LEVEL_HACK
On Sun, Feb 16, 2020 at 08:22:30AM +, Russell King - ARM Linux admin wrote: > On Sun, Feb 16, 2020 at 10:18:30AM +0200, Mike Rapoport wrote: > > From: Mike Rapoport > > > > Hi, > > > > These patches convert several architectures to use page table folding and > > remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h. > > > > The changes are mostly about mechanical replacement of pgd accessors with > > p4d > > ones and the addition of higher levels to page table traversals. > > > > All the patches were sent separately to the respective arch lists and > > maintainers hence the "v2" prefix. > > You fail to explain why this change which adds 488 additional lines of > code is desirable. Right, I should have been more explicit about it. As Christophe mentioned in his reply, removing 'HACK' and 'fixup' is an improvement. Another thing is that when all architectures behave the same it opens opportunities for cleaning up repeating definitions of page table manipulation primitives. > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > According to speedtest.net: 11.9Mbps down 500kbps up -- Sincerely yours, Mike.
Re: [PATCH v2 00/13] mm: remove __ARCH_HAS_5LEVEL_HACK
Le 16/02/2020 à 09:22, Russell King - ARM Linux admin a écrit : On Sun, Feb 16, 2020 at 10:18:30AM +0200, Mike Rapoport wrote: From: Mike Rapoport Hi, These patches convert several architectures to use page table folding and remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h. The changes are mostly about mechanical replacement of pgd accessors with p4d ones and the addition of higher levels to page table traversals. All the patches were sent separately to the respective arch lists and maintainers hence the "v2" prefix. You fail to explain why this change which adds 488 additional lines of code is desirable. The purpose of the series, ie droping a HACK, is worth it. However looking at the powerpc patch I have the feeling that this series goes behind its purpose. The number additional lines could be deeply reduced I think if we limit the patches to the strict minimum, ie just do things like below instead of adding lots of handling of useless levels. Instead of doing things like: - pud = NULL; + p4d = NULL; if (pgd_present(*pgd)) - pud = pud_offset(pgd, gpa); + p4d = p4d_offset(pgd, gpa); + else + new_p4d = p4d_alloc_one(kvm->mm, gpa); + + pud = NULL; + if (p4d_present(*p4d)) + pud = pud_offset(p4d, gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); It could be limited to: if (pgd_present(*pgd)) - pud = pud_offset(pgd, gpa); + pud = pud_offset(p4d_offset(pgd, gpa), gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); Christophe
Re: [PATCH v2 00/13] mm: remove __ARCH_HAS_5LEVEL_HACK
On Sun, Feb 16, 2020 at 10:18:30AM +0200, Mike Rapoport wrote: > From: Mike Rapoport > > Hi, > > These patches convert several architectures to use page table folding and > remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h. > > The changes are mostly about mechanical replacement of pgd accessors with p4d > ones and the addition of higher levels to page table traversals. > > All the patches were sent separately to the respective arch lists and > maintainers hence the "v2" prefix. You fail to explain why this change which adds 488 additional lines of code is desirable. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
[PATCH v2 00/13] mm: remove __ARCH_HAS_5LEVEL_HACK
From: Mike Rapoport Hi, These patches convert several architectures to use page table folding and remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h. The changes are mostly about mechanical replacement of pgd accessors with p4d ones and the addition of higher levels to page table traversals. All the patches were sent separately to the respective arch lists and maintainers hence the "v2" prefix. Geert Uytterhoeven (1): sh: fault: Modernize printing of kernel messages Mike Rapoport (12): arm/arm64: add support for folded p4d page tables h8300: remove usage of __ARCH_USE_5LEVEL_HACK hexagon: remove __ARCH_USE_5LEVEL_HACK ia64: add support for folded p4d page tables nios2: add support for folded p4d page tables openrisc: add support for folded p4d page tables powerpc: add support for folded p4d page tables sh: drop __pXd_offset() macros that duplicate pXd_index() ones sh: add support for folded p4d page tables unicore32: remove __ARCH_USE_5LEVEL_HACK asm-generic: remove pgtable-nop4d-hack.h mm: remove __ARCH_HAS_5LEVEL_HACK and include/asm-generic/5level-fixup.h arch/arm/include/asm/kvm_mmu.h| 5 +- arch/arm/include/asm/pgtable.h| 1 - arch/arm/include/asm/stage2_pgtable.h | 15 +- arch/arm/lib/uaccess_with_memcpy.c| 9 +- arch/arm/mach-sa1100/assabet.c| 2 +- arch/arm/mm/dump.c| 29 ++- arch/arm/mm/fault-armv.c | 7 +- arch/arm/mm/fault.c | 28 ++- arch/arm/mm/idmap.c | 3 +- arch/arm/mm/init.c| 2 +- arch/arm/mm/ioremap.c | 12 +- arch/arm/mm/mm.h | 2 +- arch/arm/mm/mmu.c | 35 ++- arch/arm/mm/pgd.c | 40 +++- arch/arm64/include/asm/kvm_mmu.h | 10 +- arch/arm64/include/asm/pgalloc.h | 10 +- arch/arm64/include/asm/pgtable-types.h| 5 +- arch/arm64/include/asm/pgtable.h | 37 ++-- arch/arm64/include/asm/stage2_pgtable.h | 48 +++- arch/arm64/kernel/hibernate.c | 44 +++- arch/arm64/mm/fault.c | 9 +- arch/arm64/mm/hugetlbpage.c | 15 +- arch/arm64/mm/kasan_init.c| 26 ++- arch/arm64/mm/mmu.c | 52 +++-- arch/arm64/mm/pageattr.c | 7 +- arch/h8300/include/asm/pgtable.h | 1 - arch/hexagon/include/asm/fixmap.h | 4 +- arch/hexagon/include/asm/pgtable.h| 1 - arch/ia64/include/asm/pgalloc.h | 4 +- arch/ia64/include/asm/pgtable.h | 17 +- arch/ia64/mm/fault.c | 7 +- arch/ia64/mm/hugetlbpage.c| 18 +- arch/ia64/mm/init.c | 28 ++- arch/nios2/include/asm/pgtable.h | 3 +- arch/nios2/mm/fault.c | 9 +- arch/nios2/mm/ioremap.c | 6 +- arch/openrisc/include/asm/pgtable.h | 1 - arch/openrisc/mm/fault.c | 10 +- arch/openrisc/mm/init.c | 4 +- arch/powerpc/include/asm/book3s/32/pgtable.h | 1 - arch/powerpc/include/asm/book3s/64/hash.h | 4 +- arch/powerpc/include/asm/book3s/64/pgalloc.h | 4 +- arch/powerpc/include/asm/book3s/64/pgtable.h | 58 +++-- arch/powerpc/include/asm/book3s/64/radix.h| 6 +- arch/powerpc/include/asm/nohash/32/pgtable.h | 1 - arch/powerpc/include/asm/nohash/64/pgalloc.h | 2 +- .../include/asm/nohash/64/pgtable-4k.h| 32 +-- arch/powerpc/include/asm/nohash/64/pgtable.h | 6 +- arch/powerpc/include/asm/pgtable.h| 8 + arch/powerpc/kvm/book3s_64_mmu_radix.c| 59 - arch/powerpc/lib/code-patching.c | 7 +- arch/powerpc/mm/book3s32/mmu.c| 2 +- arch/powerpc/mm/book3s32/tlb.c| 4 +- arch/powerpc/mm/book3s64/hash_pgtable.c | 4 +- arch/powerpc/mm/book3s64/radix_pgtable.c | 19 +- arch/powerpc/mm/book3s64/subpage_prot.c | 6 +- arch/powerpc/mm/hugetlbpage.c | 28 ++- arch/powerpc/mm/kasan/kasan_init_32.c | 8 +- arch/powerpc/mm/mem.c | 4 +- arch/powerpc/mm/nohash/40x.c | 4 +- arch/powerpc/mm/nohash/book3e_pgtable.c | 15 +- arch/powerpc/mm/pgtable.c | 25 ++- arch/powerpc/mm/pgtable_32.c | 28 ++- arch/powerpc/mm/pgtable_64.c | 10 +- arch/powerpc/mm/ptdump/hashpagetable.c| 20 +- arch/powerpc/mm/ptdump/ptdump.c | 22 +- arch/powerpc/xmon/xmon.c | 17 +- arch/sh/include/asm/pgtable-2level.h | 1 - arch/sh/include/asm/pgtable-3level.h
