On Wed, Feb 21, 2024 at 11:02 AM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > On Tue, Feb 20, 2024 at 6:45 PM 梦龙董 <dongmenglong.8@xxxxxxxxxxxxx> wrote: > > > > On Wed, Feb 21, 2024 at 10:35 AM 梦龙董 <dongmenglong.8@xxxxxxxxxxxxx> wrote: > > > > > > Hello, > > > > > > On Wed, Feb 21, 2024 at 9:24 AM Alexei Starovoitov > > > <alexei.starovoitov@xxxxxxxxx> wrote: > > > > > > > > On Mon, Feb 19, 2024 at 7:51 PM Menglong Dong > > > > <dongmenglong.8@xxxxxxxxxxxxx> wrote: > > > > > > > > > > For now, the BPF program of type BPF_PROG_TYPE_TRACING is not allowed to > > > > > be attached to multiple hooks, and we have to create a BPF program for > > > > > each kernel function, for which we want to trace, even through all the > > > > > program have the same (or similar) logic. This can consume extra memory, > > > > > and make the program loading slow if we have plenty of kernel function to > > > > > trace. > > > > > > > > Should this be combined with multi link ? > > > > (As was recently done for kprobe_multi and uprobe_multi). > > > > Loading fentry prog once and attaching it through many bpf_links > > > > to multiple places is a nice addition, > > > > but we should probably add a multi link right away too. > > > > > > I was planning to implement the multi link for tracing after this > > > series in another series. I can do it together with this series > > > if you prefer. > > > > > > > Should I introduce the multi link for tracing first, then this series? > > (Furthermore, this series seems not necessary.) > > What do you mean "not necessary" ? > Don't you want to still check that bpf prog access only N args > and BTF for these args matches across all attach points ? No, I means that if we should keep the "Loading fentry prog once and attaching it through many bpf_links to multiple places" and only keep the multi link. Both methods need to check the accessed args of the target.
