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... and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-avoid-overriding-min...

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------------------------------------------------------ From: Vijay Balakrishna vijayb@linux.microsoft.com 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@linux.mic... Signed-off-by: Vijay Balakrishna vijayb@linux.microsoft.com Reviewed-by: Pavel Tatashin pasha.tatashin@soleen.com Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Oleg Nesterov oleg@redhat.com Cc: Song Liu songliubraving@fb.com Cc: Andrea Arcangeli aarcange@redhat.com Cc: Michal Hocko mhocko@suse.com Cc: Allen Pais apais@microsoft.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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@linux.microsoft.com 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