[PATCH RFC v3 04/35] mm: page_alloc: Partially revert "mm: page_alloc: remove stale CMA guard code"

Alexandru Elisei
2024-01-25T16:43:45Z

The patch f945116e4e19 ("mm: page_alloc: remove stale CMA guard code")
removed the CMA filter when allocating from the MIGRATE_MOVABLE pcp list
because CMA is always allowed when __GFP_MOVABLE is set.

With the introduction of the arch_alloc_cma() function, the above is not
true anymore, so bring back the filter.

This is a partially revert because the stale comment remains removed.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
mm/page_alloc.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a96d47a6393e..0fa34bcfb1af 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2897,10 +2897,17 @@ struct page *rmqueue(struct zone *preferred_zone,
WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));

if (likely(pcp_allowed_order(order))) {
- page = rmqueue_pcplist(preferred_zone, zone, order,
- migratetype, alloc_flags);
- if (likely(page))
- goto out;
+ /*
+ * MIGRATE_MOVABLE pcplist could have the pages on CMA area and
+ * we need to skip it when CMA area isn't allowed.
+ */
+ if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
+ migratetype != MIGRATE_MOVABLE) {
+ page = rmqueue_pcplist(preferred_zone, zone, order,
+ migratetype, alloc_flags);
+ if (likely(page))
+ goto out;
+ }
}

page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
--
2.43.0