On Tue, Jun 20, 2023 at 7:51 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > On Mon, 19 Jun 2023 02:43:58 +0200 > Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > > > Now you might argue that it _is_ a "hotpath" due to the BPF usage, but > > then even more so as any intermediate wrapper which converts from one > > data representation to another data representation is not going to > > increase performance, right? > > Just as a side note. BPF can not attach its return calling code to > functions that have more than 6 parameters (3 on 32 bit x86), because of > the way BPF return path trampoline works. It is a requirement that all > parameters live in registers, and none on the stack. It's actually 7 and that restriction is being lifted. The patch set to attach to <= 12 is being discussed.
