From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
If a folio has an increased reference count, folio_try_get() will acquire
it, perform necessary operations, and then release it. In the case of a
poisoned folio without an elevated reference count (which is unlikely for
memory-failure), folio_try_get() will simply bypass it.
Therefore, relocate the folio_try_get() function, responsible for checking
and acquiring this reference count at first.
Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx>
---
mm/memory_hotplug.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3de661e57e92..3669b3e2d962 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1795,12 +1795,12 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (folio_test_large(folio))
pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
- /*
- * HWPoison pages have elevated reference counts so the migration would
- * fail on them. It also doesn't make any sense to migrate them in the
- * first place. Still try to unmap such a page in case it is still mapped
- * (keep the unmap as the catch all safety net).
- */
+ if (!folio_try_get(folio))
+ continue;
+
+ if (unlikely(page_folio(page) != folio))
+ goto put_folio;
+
if (folio_test_hwpoison(folio) ||
(folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) {
if (WARN_ON(folio_test_lru(folio)))
@@ -1808,14 +1808,8 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (folio_mapped(folio))
unmap_poisoned_folio(folio, pfn, false);
- continue;
- }
-
- if (!folio_try_get(folio))
- continue;
-
- if (unlikely(page_folio(page) != folio))
goto put_folio;
+ }
if (!isolate_folio_to_list(folio, &source)) {
if (__ratelimit(&migrate_rs)) {
--
2.43.0
