git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 4aab2be0983031a05cb4a19696c9da5749523426 Mon Sep 17 00:00:00 2001
   2 From: Vijay Balakrishna <vijayb@linux.microsoft.com>
   3 Date: Sat, 10 Oct 2020 23:16:40 -0700
   4 Subject: mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged
   5
   6 From: Vijay Balakrishna <vijayb@linux.microsoft.com>
   7
   8 commit 4aab2be0983031a05cb4a19696c9da5749523426 upstream.
   9
  10 When memory is hotplug added or removed the min_free_kbytes should be
  11 recalculated based on what is expected by khugepaged.  Currently after
  12 hotplug, min_free_kbytes will be set to a lower default and higher
  13 default set when THP enabled is lost.
  14
  15 This change restores min_free_kbytes as expected for THP consumers.
  16
  17 [vijayb@linux.microsoft.com: v5]
  18   Link: https://lkml.kernel.org/r/1601398153-5517-1-git-send-email-vijayb@linux.microsoft.com
  19
  20 Fixes: f000565adb77 ("thp: set recommended min free kbytes")
  21 Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
  22 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  23 Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
  24 Acked-by: Michal Hocko <mhocko@suse.com>
  25 Cc: Allen Pais <apais@microsoft.com>
  26 Cc: Andrea Arcangeli <aarcange@redhat.com>
  27 Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
  28 Cc: Oleg Nesterov <oleg@redhat.com>
  29 Cc: Song Liu <songliubraving@fb.com>
  30 Cc: <stable@vger.kernel.org>
  31 Link: https://lkml.kernel.org/r/1600305709-2319-2-git-send-email-vijayb@linux.microsoft.com
  32 Link: https://lkml.kernel.org/r/1600204258-13683-1-git-send-email-vijayb@linux.microsoft.com
  33 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  34 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  35
  36 ---
  37  include/linux/khugepaged.h |    5 +++++
  38  mm/khugepaged.c            |   13 +++++++++++--
  39  mm/page_alloc.c            |    3 +++
  40  3 files changed, 19 insertions(+), 2 deletions(-)
  41
  42 --- a/include/linux/khugepaged.h
  43 +++ b/include/linux/khugepaged.h
  44 @@ -13,6 +13,7 @@ extern int __khugepaged_enter(struct mm_
  45  extern void __khugepaged_exit(struct mm_struct *mm);
  46  extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
  47                                       unsigned long vm_flags);
  48 +extern void khugepaged_min_free_kbytes_update(void);
  49
  50  #define khugepaged_enabled()                                          \
  51         (transparent_hugepage_flags &                                  \
  52 @@ -70,6 +71,10 @@ static inline int khugepaged_enter_vma_m
  53  {
  54         return 0;
  55  }
  56 +
  57 +static inline void khugepaged_min_free_kbytes_update(void)
  58 +{
  59 +}
  60  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  61
  62  #endif /* _LINUX_KHUGEPAGED_H */
  63 --- a/mm/khugepaged.c
  64 +++ b/mm/khugepaged.c
  65 @@ -50,6 +50,9 @@ enum scan_result {
  66  #define CREATE_TRACE_POINTS
  67  #include <trace/events/huge_memory.h>
  68
  69 +static struct task_struct *khugepaged_thread __read_mostly;
  70 +static DEFINE_MUTEX(khugepaged_mutex);
  71 +
  72  /* default scan 8*512 pte (or vmas) every 30 second */
  73  static unsigned int khugepaged_pages_to_scan __read_mostly;
  74  static unsigned int khugepaged_pages_collapsed;
  75 @@ -1948,8 +1951,6 @@ static void set_recommended_min_free_kby
  76
  77  int start_stop_khugepaged(void)
  78  {
  79 -       static struct task_struct *khugepaged_thread __read_mostly;
  80 -       static DEFINE_MUTEX(khugepaged_mutex);
  81         int err = 0;
  82
  83         mutex_lock(&khugepaged_mutex);
  84 @@ -1976,3 +1977,11 @@ fail:
  85         mutex_unlock(&khugepaged_mutex);
  86         return err;
  87  }
  88 +
  89 +void khugepaged_min_free_kbytes_update(void)
  90 +{
  91 +       mutex_lock(&khugepaged_mutex);
  92 +       if (khugepaged_enabled() && khugepaged_thread)
  93 +               set_recommended_min_free_kbytes();
  94 +       mutex_unlock(&khugepaged_mutex);
  95 +}
  96 --- a/mm/page_alloc.c
  97 +++ b/mm/page_alloc.c
  98 @@ -64,6 +64,7 @@
  99  #include <linux/page_owner.h>
 100  #include <linux/kthread.h>
 101  #include <linux/memcontrol.h>
 102 +#include <linux/khugepaged.h>
 103
 104  #include <asm/sections.h>
 105  #include <asm/tlbflush.h>
 106 @@ -6785,6 +6786,8 @@ int __meminit init_per_zone_wmark_min(vo
 107         setup_min_slab_ratio();
 108  #endif
 109
 110 +       khugepaged_min_free_kbytes_update();
 111 +
 112         return 0;
 113  }
 114  postcore_initcall(init_per_zone_wmark_min)