On Fri, May 20, 2022 at 12:24 AM Tejun Heo <tj@xxxxxxxxxx> wrote: > > On Fri, May 20, 2022 at 01:21:30AM +0000, Yosry Ahmed wrote: > > Add cgroup_rstat_updated() and cgroup_rstat_flush() kfuncs to bpf > > tracing programs. bpf programs that make use of rstat can use these > > functions to inform rstat when they update stats for a cgroup, and when > > they need to flush the stats. > > > > Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx> > > Do patch 1 and 2 need to be separate? Also, can you explain and comment why > it's __weak? I will squash them in the next version. As for the declaration, I took the __weak annotation from Alexei's reply to the previous version. I thought it had something to do with how fentry progs attach to functions with BTF and all. When I try the same code with a static noinline declaration instead, fentry attachment fails to find the BTF type ID of bpf_rstat_flush. When I try it with just noinline (without __weak), the fentry program attaches, but is never invoked. I tried looking at the attach code but I couldn't figure out why this happens. In retrospect, I should have given this more thought. It would be great if Alexei could shed some light on this. > > Thanks. > > -- > tejun