The patch titled
Subject: mm: khugepaged: avoid overriding min_free_kbytes set by user
has been added to the -mm tree. Its filename is
mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user.patch
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------------------------------------------------------
From: Vijay Balakrishna <vijayb@xxxxxxxxxxxxxxxxxxx>
Subject: mm: khugepaged: avoid overriding min_free_kbytes set by user
set_recommended_min_free_kbytes need to honor min_free_kbytes set by the
user. Post start-of-day THP enable or memory hotplug operations can lose
user specified min_free_kbytes, in particular when it is higher than
calculated recommended value. Also modifying "recommended_min" variable
type to "int" from "unsigned long" to avoid undesired result noticed
during testing. It is due to comparing "unsigned long" with "int" type.
Link: https://lkml.kernel.org/r/1600204258-13683-2-git-send-email-vijayb@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Vijay Balakrishna <vijayb@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Allen Pais <apais@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/khugepaged.c~mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user
+++ a/mm/khugepaged.c
@@ -2253,7 +2253,7 @@ static void set_recommended_min_free_kby
{
struct zone *zone;
int nr_zones = 0;
- unsigned long recommended_min;
+ int recommended_min;
for_each_populated_zone(zone) {
/*
@@ -2280,12 +2280,12 @@ static void set_recommended_min_free_kby
/* don't ever allow to reserve more than 5% of the lowmem */
recommended_min = min(recommended_min,
- (unsigned long) nr_free_buffer_pages() / 20);
+ (int) nr_free_buffer_pages() / 20);
recommended_min <<= (PAGE_SHIFT-10);
- if (recommended_min > min_free_kbytes) {
+ if (recommended_min > user_min_free_kbytes) {
if (user_min_free_kbytes >= 0)
- pr_info("raising min_free_kbytes from %d to %lu to help transparent hugepage allocations\n",
+ pr_info("raising min_free_kbytes from %d to %d to help transparent hugepage allocations\n",
min_free_kbytes, recommended_min);
min_free_kbytes = recommended_min;
_
Patches currently in -mm which might be from vijayb@xxxxxxxxxxxxxxxxxxx are
mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged.patch
mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user.patch
