On Tue, Jan 14, 2025 at 2:21 AM David Hildenbrand [off-list ref] wrote:

On 13.01.25 14:19, David Hildenbrand wrote:

quoted

On 13.01.25 04:38, Barry Song wrote:

quoted

From: Barry Song <redacted>

The refcount may be temporarily or long-term increased, but this does
not change the fundamental nature of the folio already being lazy-
freed. Therefore, we only reset 'swapbacked' when we are certain the
folio is dirty and not droppable.

Suggested-by: David Hildenbrand <redacted>
Signed-off-by: Barry Song <redacted>
---

Acked-by: David Hildenbrand <redacted>

Thanks!

Ah, should this have a Fixes: ?

That makes sense to me.

Because of a speculative reference, we might not reclaim MADV_FREE
folios as we silently mark them as swapbacked again, which sounds fairly
wrong.

I assume the tag should be applied to Mauricio's commit 6c8e2a256915a2 ("mm:
fix race between MADV_FREE reclaim and blkdev direct IO read") and  also
Mauricio is CC'ed.

--
Cheers,

David / dhildenb

Thanks
Barry