[RFC PATCH v12 18/26] mm/page_alloc: retry 3 times to take pcp pages on luf check failure

Byungchul Park
2025-02-20T05:36:06Z

mm/page_alloc.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3032fedd8392b..0b6e7f235c4a1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3339,6 +3339,12 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
{
struct page *page;

+ /*
+ * give up taking page from pcp if it fails to take pcp page
+ * 3 times due to the tlb shootdownable issue.
+ */
+ int try_luf_pages = 3;
+
do {
if (list_empty(list)) {
int batch = nr_pcp_alloc(pcp, zone, order);
@@ -3353,11 +3359,21 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
return NULL;
}

- page = list_first_entry(list, struct page, pcp_list);
- if (!luf_takeoff_check_and_fold(page))
+ list_for_each_entry(page, list, pcp_list) {
+ if (luf_takeoff_check_and_fold(page)) {
+ list_del(&page->pcp_list);
+ pcp->count -= 1 << order;
+ break;
+ }
+ if (!--try_luf_pages)
+ return NULL;
+ }
+
+ /*
+ * If all the pages in the list fails...
+ */
+ if (list_entry_is_head(page, list, pcp_list))
return NULL;
- list_del(&page->pcp_list);
- pcp->count -= 1 << order;
} while (check_new_pages(page, order));

return page;
--
2.17.1