target/linux/generic/backport-5.15/020-v6.1-02-mm-x86-add-CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG.patch

   1 From 493de1c4b0f2cd909169401da8c445f6c8a7e29d Mon Sep 17 00:00:00 2001
   2 From: Yu Zhao <yuzhao@google.com>
   3 Date: Sun, 18 Sep 2022 01:59:59 -0600
   4 Subject: [PATCH 02/29] mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Some architectures support the accessed bit in non-leaf PMD entries, e.g.,
  10 x86 sets the accessed bit in a non-leaf PMD entry when using it as part of
  11 linear address translation [1].  Page table walkers that clear the
  12 accessed bit may use this capability to reduce their search space.
  13
  14 Note that:
  15 1. Although an inline function is preferable, this capability is added
  16    as a configuration option for consistency with the existing macros.
  17 2. Due to the little interest in other varieties, this capability was
  18    only tested on Intel and AMD CPUs.
  19
  20 Thanks to the following developers for their efforts [2][3].
  21   Randy Dunlap <rdunlap@infradead.org>
  22   Stephen Rothwell <sfr@canb.auug.org.au>
  23
  24 [1]: Intel 64 and IA-32 Architectures Software Developer's Manual
  25      Volume 3 (June 2021), section 4.8
  26 [2] https://lore.kernel.org/r/bfdcc7c8-922f-61a9-aa15-7e7250f04af7@infradead.org/
  27 [3] https://lore.kernel.org/r/20220413151513.5a0d7a7e@canb.auug.org.au/
  28
  29 Link: https://lkml.kernel.org/r/20220918080010.2920238-3-yuzhao@google.com
  30 Signed-off-by: Yu Zhao <yuzhao@google.com>
  31 Reviewed-by: Barry Song <baohua@kernel.org>
  32 Acked-by: Brian Geffon <bgeffon@google.com>
  33 Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
  34 Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
  35 Acked-by: Steven Barrett <steven@liquorix.net>
  36 Acked-by: Suleiman Souhlal <suleiman@google.com>
  37 Tested-by: Daniel Byrne <djbyrne@mtu.edu>
  38 Tested-by: Donald Carr <d@chaos-reins.com>
  39 Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
  40 Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
  41 Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
  42 Tested-by: Sofia Trinh <sofia.trinh@edi.works>
  43 Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
  44 Cc: Andi Kleen <ak@linux.intel.com>
  45 Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
  46 Cc: Catalin Marinas <catalin.marinas@arm.com>
  47 Cc: Dave Hansen <dave.hansen@linux.intel.com>
  48 Cc: Hillf Danton <hdanton@sina.com>
  49 Cc: Jens Axboe <axboe@kernel.dk>
  50 Cc: Johannes Weiner <hannes@cmpxchg.org>
  51 Cc: Jonathan Corbet <corbet@lwn.net>
  52 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  53 Cc: Matthew Wilcox <willy@infradead.org>
  54 Cc: Mel Gorman <mgorman@suse.de>
  55 Cc: Miaohe Lin <linmiaohe@huawei.com>
  56 Cc: Michael Larabel <Michael@MichaelLarabel.com>
  57 Cc: Michal Hocko <mhocko@kernel.org>
  58 Cc: Mike Rapoport <rppt@kernel.org>
  59 Cc: Mike Rapoport <rppt@linux.ibm.com>
  60 Cc: Peter Zijlstra <peterz@infradead.org>
  61 Cc: Qi Zheng <zhengqi.arch@bytedance.com>
  62 Cc: Tejun Heo <tj@kernel.org>
  63 Cc: Vlastimil Babka <vbabka@suse.cz>
  64 Cc: Will Deacon <will@kernel.org>
  65 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  66 ---
  67  arch/Kconfig                   | 8 ++++++++
  68  arch/x86/Kconfig               | 1 +
  69  arch/x86/include/asm/pgtable.h | 3 ++-
  70  arch/x86/mm/pgtable.c          | 5 ++++-
  71  include/linux/pgtable.h        | 4 ++--
  72  5 files changed, 17 insertions(+), 4 deletions(-)
  73
  74 --- a/arch/Kconfig
  75 +++ b/arch/Kconfig
  76 @@ -1298,6 +1298,14 @@ config ARCH_HAS_ELFCORE_COMPAT
  77  config ARCH_HAS_PARANOID_L1D_FLUSH
  78         bool
  79
  80 +config ARCH_HAS_NONLEAF_PMD_YOUNG
  81 +       bool
  82 +       help
  83 +         Architectures that select this option are capable of setting the
  84 +         accessed bit in non-leaf PMD entries when using them as part of linear
  85 +         address translations. Page table walkers that clear the accessed bit
  86 +         may use this capability to reduce their search space.
  87 +
  88  source "kernel/gcov/Kconfig"
  89
  90  source "scripts/gcc-plugins/Kconfig"
  91 --- a/arch/x86/Kconfig
  92 +++ b/arch/x86/Kconfig
  93 @@ -85,6 +85,7 @@ config X86
  94         select ARCH_HAS_PMEM_API                if X86_64
  95         select ARCH_HAS_PTE_DEVMAP              if X86_64
  96         select ARCH_HAS_PTE_SPECIAL
  97 +       select ARCH_HAS_NONLEAF_PMD_YOUNG       if PGTABLE_LEVELS > 2
  98         select ARCH_HAS_UACCESS_FLUSHCACHE      if X86_64
  99         select ARCH_HAS_COPY_MC                 if X86_64
 100         select ARCH_HAS_SET_MEMORY
 101 --- a/arch/x86/include/asm/pgtable.h
 102 +++ b/arch/x86/include/asm/pgtable.h
 103 @@ -817,7 +817,8 @@ static inline unsigned long pmd_page_vad
 104
 105  static inline int pmd_bad(pmd_t pmd)
 106  {
 107 -       return (pmd_flags(pmd) & ~_PAGE_USER) != _KERNPG_TABLE;
 108 +       return (pmd_flags(pmd) & ~(_PAGE_USER | _PAGE_ACCESSED)) !=
 109 +              (_KERNPG_TABLE & ~_PAGE_ACCESSED);
 110  }
 111
 112  static inline unsigned long pages_to_mb(unsigned long npg)
 113 --- a/arch/x86/mm/pgtable.c
 114 +++ b/arch/x86/mm/pgtable.c
 115 @@ -550,7 +550,7 @@ int ptep_test_and_clear_young(struct vm_
 116         return ret;
 117  }
 118
 119 -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 120 +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
 121  int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 122                               unsigned long addr, pmd_t *pmdp)
 123  {
 124 @@ -562,6 +562,9 @@ int pmdp_test_and_clear_young(struct vm_
 125
 126         return ret;
 127  }
 128 +#endif
 129 +
 130 +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 131  int pudp_test_and_clear_young(struct vm_area_struct *vma,
 132                               unsigned long addr, pud_t *pudp)
 133  {
 134 --- a/include/linux/pgtable.h
 135 +++ b/include/linux/pgtable.h
 136 @@ -212,7 +212,7 @@ static inline int ptep_test_and_clear_yo
 137  #endif
 138
 139  #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
 140 -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 141 +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
 142  static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 143                                             unsigned long address,
 144                                             pmd_t *pmdp)
 145 @@ -233,7 +233,7 @@ static inline int pmdp_test_and_clear_yo
 146         BUILD_BUG();
 147         return 0;
 148  }
 149 -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 150 +#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */
 151  #endif
 152
 153  #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH