On 22.04.25 04:52, Kairui Song wrote:
On Sun, Apr 20, 2025 at 12:35 AM Kairui Song <ryncsn@xxxxxxxxx> wrote:
On Sun, Apr 20, 2025 at 12:32 AM David Hildenbrand <david@xxxxxxxxxx> wrote:
On 19.04.25 18:25, David Hildenbrand wrote:
Oh, re-reading the condition 3 times, I realize that the sanity check is wrong ...
diff --git a/mm/memory.c b/mm/memory.c
index 037b6ce211f1f..a17eeef3f1f89 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3789,7 +3789,7 @@ static bool __wp_can_reuse_large_anon_folio(struct folio *folio,
/* Stabilize the mapcount vs. refcount and recheck. */
folio_lock_large_mapcount(folio);
- VM_WARN_ON_ONCE(folio_large_mapcount(folio) < folio_ref_count(folio));
+ VM_WARN_ON_ONCE(folio_large_mapcount(folio) > folio_ref_count(folio));
Ah, now it makes sense to me now :)
Thanks for the quick response.
if (folio_test_large_maybe_mapped_shared(folio))
goto unlock;
Our refcount must be at least the mapcount, that's what we want to assert.
Can you test and send a fix patch if that makes it fly for you?
Sure I'll keep the testing, I think it will just fix it, I have a few
WARN_ON_FOLIO reports all reporting mapcount is smaller than refcount.
Hi David,
I'm no longer seeing any warning after this, it fixed the problem well.
Cool, can you send a fix?
--
Cheers,
David / dhildenb
