Cc Johannes, Zi and Vlastimil.
On 2024/6/4 17:14, yangge1116@xxxxxxx wrote:
From: yangge <yangge1116@xxxxxxx>
Since commit 5d0a661d808f ("mm/page_alloc: use only one PCP list for
THP-sized allocations") no longer differentiates the migration type
of pages in THP-sized PCP list, it's possible to get a CMA page from
the list, in some cases, it's not acceptable, for example, allocating
a non-CMA page with PF_MEMALLOC_PIN flag returns a CMA page.
The patch forbids allocating non-CMA THP-sized page from THP-sized
PCP list to avoid the issue above.
Fixes: 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations")
Signed-off-by: yangge <yangge1116@xxxxxxx>
---
mm/page_alloc.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e22ce5..0bdf471 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2987,10 +2987,20 @@ struct page *rmqueue(struct zone *preferred_zone,
WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
if (likely(pcp_allowed_order(order))) {
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
+ order != HPAGE_PMD_ORDER) {
Seems you will also miss the non-CMA THP from the PCP, so I wonder if we
can add a migratetype comparison in __rmqueue_pcplist(), and if it's not
suitable, then fallback to buddy?
+ page = rmqueue_pcplist(preferred_zone, zone, order,
+ migratetype, alloc_flags);
+ if (likely(page))
+ goto out;
+ }
+#else
page = rmqueue_pcplist(preferred_zone, zone, order,
migratetype, alloc_flags);
if (likely(page))
goto out;
+#endif
}
page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
