On Mon, 1 Apr 2024 10:28:17 +0800 梦龙董 <dongmenglong.8@xxxxxxxxxxxxx> wrote: > On Sun, Mar 31, 2024 at 3:34 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > > > On Sat, 30 Mar 2024 11:18:29 +0800 > > 梦龙董 <dongmenglong.8@xxxxxxxxxxxxx> wrote: > > > > > > If you really want to have thousands of functions, why not just register it > > > > with ftrace itself. It will give you the arguments via the ftrace_regs > > > > structure. Can't you just register a program as the callback? > > > > > > > > > > Ennn...I don't understand. The main purpose for > > > me to use TRACING is: > > > > > > 1. we can directly access the memory, which is more > > > efficient. > > > > I'm not sure what you mean by the above. Access what memory? > > > > We need to use the helper of bpf_probe_read_kernel > when we read "skb->sk" in kprobe, and the "skb" is the > 1st arg in ip_rcv(). And we can directly read "skb->sk" > in tracing, which is more efficient. Isn't it? If you add a ftrace_ops function handler that calls a BPF program, I don't see why you can't just give it the parameters it needs instead of using bpf helpers. It's no different than using a trampoline to do the same thing. -- Steve
