On Sun, 14 May 2023 23:12:11 +0900 "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote: > From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> > > Add the '$args' meta fetch argument for function-entry probe events. This > will be expanded to the all arguments of the function and the tracepoint > using BTF function argument information. > > e.g. > # echo 'p vfs_read $args' >> dynamic_events > # echo 'f vfs_write $args' >> dynamic_events > # echo 't sched_overutilized_tp $args' >> dynamic_events > # cat dynamic_events > p:kprobes/p_vfs_read_0 vfs_read file=file buf=buf count=count pos=pos > f:fprobes/vfs_write__entry vfs_write file=file buf=buf count=count pos=pos > t:tracepoints/sched_overutilized_tp sched_overutilized_tp rd=rd overutilized=overutilized > > NOTE: This is not like other $-vars, you can not use this $args as a > part of fetch args, e.g. specifying name "foo=$args" and using it in > dereferences "+0($args)" will lead a parse error. > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> > --- > Changes in v10: > - Change $$args to $args so that user can use $$ for current task's pid. I hate coming up with new apis, because you never know if what you pick is correct ;-) And then you are stuck with whatever you decided on. :-/ I know I suggested $args, but since it is special, should we call it "$arg*" ? That way it follows bash wildcard semantics? # echo 'p vfs_read $arg*' >> dynamic_events I think that is more along the lines of what people would expect. What do you think? -- Steve > Changes in v6: > - update patch description. > --- > kernel/trace/trace_fprobe.c | 21 ++++++++- > kernel/trace/trace_kprobe.c | 23 ++++++++-- > kernel/trace/trace_probe.c | 98 +++++++++++++++++++++++++++++++++++++++++++ > kernel/trace/trace_probe.h | 10 ++++ > 4 files changed, 144 insertions(+), 8 deletions(-) > >
