On 2023/10/9 15:53, Eric Dumazet wrote:

On Mon, Oct 9, 2023 at 5:07 AM Yajun Deng [off-list ref] wrote:

quoted

'this_cpu_read + this_cpu_write' and 'pr_info + this_cpu_inc' will make
the trace work well.

They all have 'pop' instructions in them. This may be the key to making
the trace work well.

Hi all,

I need your help on percpu and ftrace.

I do not think you made sure netdev_core_stats_inc() was never inlined.

Adding more code in it is simply changing how the compiler decides to
inline or not.

Yes, you are right. It needs to add the 'noinline' prefix. The 
disassembly code will have 'pop'

instruction.

Thanks.