On Tue, Jul 15, 2025 at 9:54 AM David Hildenbrand [off-list ref] wrote:

On 14.07.25 02:31, Nico Pache wrote:

quoted

The khugepaged daemon and madvise_collapse have two different
implementations that do almost the same thing.

Create collapse_single_pmd to increase code reuse and create an entry
point to these two users.

Refactor madvise_collapse and collapse_scan_mm_slot to use the new
collapse_single_pmd function. This introduces a minor behavioral change
that is most likely an undiscovered bug. The current implementation of
khugepaged tests collapse_test_exit_or_disable before calling
collapse_pte_mapped_thp, but we weren't doing it in the madvise_collapse
case. By unifying these two callers madvise_collapse now also performs
this check.

Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Nico Pache <npache@redhat.com>
---
  mm/khugepaged.c | 95 +++++++++++++++++++++++++------------------------
  1 file changed, 49 insertions(+), 46 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index eb0babb51868..47a80638af97 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c

@@ -2362,6 +2362,50 @@ static int collapse_scan_file(struct mm_struct *mm, unsigned long addr,
      return result;
  }

+/*
+ * Try to collapse a single PMD starting at a PMD aligned addr, and return
+ * the results.
+ */
+static int collapse_single_pmd(unsigned long addr,
+                                struct vm_area_struct *vma, bool *mmap_locked,
+                                struct collapse_control *cc)

Nit: we tend to use two-tabs indent here.

Thanks I cleaned up these indentations!

Nice cleanup!

Acked-by: David Hildenbrand <redacted>

Much appreciated :)

--
Cheers,

David / dhildenb