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SubjectRe: [PATCH v4 1/2] bpf: avoid grabbing spin_locks of all cpus when no free elems
On Wed, Jun 1, 2022 at 10:42 AM Feng zhou <zhoufeng.zf@bytedance.com> wrote:
>
> static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
> @@ -130,14 +134,19 @@ static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s)
> orig_cpu = cpu = raw_smp_processor_id();
> while (1) {
> head = per_cpu_ptr(s->freelist, cpu);
> + if (READ_ONCE(head->is_empty))
> + goto next_cpu;
> raw_spin_lock(&head->lock);
> node = head->first;
> if (node) {

extra bool is unnecessary.
just READ_ONCE(head->first)

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