Where is trace_netif_rx_entry function defined in Linux kernel?

Question

in linux kernel source codes, net/core/dev.c, the function netif_rx() calls trace_netif_rx_entry():

int netif_rx(struct sk_buff *skb)
{
    trace_netif_rx_entry(skb);
    return netif_rx_internal(skb);
}

However, I searched via grep and could not find the definition of trace_netif_rx_entry in the source codes. Then I googled still no answer. Could anyone help ?

Answer 1

I know the reason: a trick named Linux trace point