+ mm-damon-ops-common-putback-folios-on-invalid-migrate-nid.patch added to mm-hotfixes-unstable branch

The patch titled
     Subject: mm/damon/ops-common: putback folios on invalid migrate nid
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-damon-ops-common-putback-folios-on-invalid-migrate-nid.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-ops-common-putback-folios-on-invalid-migrate-nid.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: liyouhong <[email protected]>
Subject: mm/damon/ops-common: putback folios on invalid migrate nid
Date: Sun, 26 Jul 2026 09:48:15 +0800

damon_pa_migrate() and damos_va_migrate() isolate folios into a local list
and then call damon_migrate_pages().  When target_nid is invalid
(including the scheme default NUMA_NO_NODE / -1), damon_migrate_pages()
returns early without putting the folios back to the LRU.

Callers then discard the list head while those folios remain isolated with
an extra reference taken by folio_isolate_lru().  The pages stay off the
LRU for as long as the mapping exists (anon active+inactive counts drop
while RSS does not), and the leftover references can pin the pages after
the mapping is gone.

Put the folios back on the invalid-nid path so ignored migration requests
still return them to the LRU.

Link: https://lore.kernel.org/[email protected]
Fixes: 7e6c3130690a ("mm/damon/ops-common: ignore migration request to invalid nodes")
Assisted-by: Cursor:grok-4.5
Reviewed-by: SJ Park <[email protected]>
Signed-off-by: liyouhong <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/damon/ops-common.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/mm/damon/ops-common.c~mm-damon-ops-common-putback-folios-on-invalid-migrate-nid
+++ a/mm/damon/ops-common.c
@@ -392,8 +392,15 @@ unsigned long damon_migrate_pages(struct
 		return nr_migrated;
 
 	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
-			!node_state(target_nid, N_MEMORY))
+			!node_state(target_nid, N_MEMORY)) {
+		while (!list_empty(folio_list)) {
+			struct folio *folio = lru_to_folio(folio_list);
+
+			list_del(&folio->lru);
+			folio_putback_lru(folio);
+		}
 		return nr_migrated;
+	}
 
 	noreclaim_flag = memalloc_noreclaim_save();
 
_

Patches currently in -mm which might be from [email protected] are

mm-damon-ops-common-putback-folios-on-invalid-migrate-nid.patch