Re: [stable-6.6.y] mm: khugepaged refuses to freeze

From: David Hildenbrand (Arm)

Date: Tue Feb 10 2026 - 05:21:25 EST


On 2/10/26 11:07, Baolin Wang wrote:


On 2/10/26 11:21 AM, Sergey Senozhatsky wrote:
On (26/02/06 10:00), David Hildenbrand (Arm) wrote:

Right, mimicking what kswapd does sound reasonable!

I may be missing something, as I'm not seeing dev_pm_ops in vmscan code.
Would something like this work?

---

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index fa6a018b20a8..c5d89ec223d3 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -394,8 +394,12 @@ static inline int hpage_collapse_test_exit(struct mm_struct *mm)
  static inline int hpage_collapse_test_exit_or_disable(struct mm_struct *mm)
  {
+    bool was_frozen;
+    int ret = kthread_freezable_should_stop(&was_frozen);
+
      return hpage_collapse_test_exit(mm) ||
-        mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
+        mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) ||
+        was_frozen || ret;
  }

Since the hpage_collapse_test_exit_or_disable() can be called by madvise_callapse(), which is not a kernel thread.

Which raises the question whether we should forward that context (khugepaged vs. madvise) to hpage_collapse_test_exit_or_disable().

--
Cheers,

David