@@ -171,9 +171,24 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node)
memcg = get_memcg(c);
old_memcg = set_active_memcg(memcg);
for (i = 0; i < cnt; i++) {
- obj = __alloc(c, node);
- if (!obj)
- break;
+ /*
+ * free_by_rcu is only manipulated by irq work refill_work().
+ * IRQ works on the same CPU are called sequentially, so it is
+ * safe to use __llist_del_first() here. If alloc_bulk() is
+ * invoked by the initial prefill, there will be no running
+ * refill_work(), so __llist_del_first() is fine as well.
+ *
+ * In most cases, objects on free_by_rcu are from the same CPU.
+ * If some objects come from other CPUs, it doesn't incur any
+ * harm because NUMA_NO_NODE means the preference for current
+ * numa node and it is not a guarantee.
+ */
+ obj = __llist_del_first(&c->free_by_rcu);
+ if (!obj) {
+ obj = __alloc(c, node);
+ if (!obj)
+ break;
+ }
if (IS_ENABLED(CONFIG_PREEMPT_RT))
/* In RT irq_work runs in per-cpu kthread, so disable
* interrupts to avoid preemption and interrupts and