0e4b01df8659 had a bunch of fixups to use the right division method.
However, it seems that after all that it still wasn't right -- div_u64
takes a 32-bit divisor.
The headroom is still large (2^32 pages), so on mundane systems you
won't hit this, but this should definitely be fixed.
Fixes: 0e4b01df8659 ("mm, memcg: throttle allocators when failing reclaim over memory.high")
Reported-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Chris Down <chris@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: kernel-team@xxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 5.4.x
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 63bb6a2aab81..a70206e516fe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2339,7 +2339,7 @@ void mem_cgroup_handle_over_high(void)
*/
clamped_high = max(high, 1UL);
- overage = div_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT,
+ overage = div64_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT,
clamped_high);
penalty_jiffies = ((u64)overage * overage * HZ)
--
2.25.1
