On Wed, Feb 21, 2024 at 11:18 AM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Tue, Feb 20, 2024 at 7:06 PM 梦龙董 dongmenglong.8@bytedance.com wrote:
On Wed, Feb 21, 2024 at 11:02 AM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Tue, Feb 20, 2024 at 6:45 PM 梦龙董 dongmenglong.8@bytedance.com wrote:
On Wed, Feb 21, 2024 at 10:35 AM 梦龙董 dongmenglong.8@bytedance.com wrote:
Hello,
On Wed, Feb 21, 2024 at 9:24 AM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Mon, Feb 19, 2024 at 7:51 PM Menglong Dong dongmenglong.8@bytedance.com 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.
I suspect supporting multi link only is better, since the amount of kernel code to maintain will be less.
Okay!