Currently, At worst, the pcp->free_count can be
(batch - 1 + (1 << MAX_ORDER)), which may exceed the expected max value of
(batch << CONFIG_PCP_BATCH_SCALE_MAX).
This issue was identified through code review, and no real problems have
been observed.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
---
mm/page_alloc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e22ce5675ca..8e2f4e1ab4f2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2534,7 +2534,8 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp,
pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER;
}
if (pcp->free_count < (batch << CONFIG_PCP_BATCH_SCALE_MAX))
- pcp->free_count += (1 << order);
+ pcp->free_count = min(pcp->free_count + (1 << order),
+ batch << CONFIG_PCP_BATCH_SCALE_MAX);
high = nr_pcp_high(pcp, zone, batch, free_high);
if (pcp->count >= high) {
free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high),
--
2.43.5
