On 6/28/2023 9:56 AM, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> Let free_all() helper return the number of freed elements.
> It's not used in this patch, but helps in debug/development of bpf_mem_alloc.
>
> For example this diff for __free_rcu():
> - free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size);
> + printk("cpu %d freed %d objs after tasks trace\n", raw_smp_processor_id(),
> + free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size));
>
> would show how busy RCU tasks trace is.
> In artificial benchmark where one cpu is allocating and different cpu is freeing
> the RCU tasks trace won't be able to keep up and the list of objects
> would keep growing from thousands to millions and eventually OOMing.
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Acked-by: Hou Tao <houtao1@xxxxxxxxxx>
