On Fri, 10 Nov 2023 10:51:54 +0900 Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote: > So this patch registers ftrace_ops for each fgraph_ops to ftrace. > This means that the ftrace_graph_func() will be called twice or more > on the same function. > Thus should I call ftrace_startup() once when the first fgraph_ops > is registered? > No, it's not enough. Actually each fgraph_ops can have different filters. > We need to define a shared filter and combine new filters to one and > use it. We also need to do it when a fgraph is unregistered. > > Is there any function which makes a new filter from two (or more) filters? So I'm guessing that we need to have a fgraph_set_filter*() operations? When one gets added, it needs to update the ftrace_ops to include the added functions. Or we need to have a way to create a new hash from all the registered fgraph_ops, and have that for the ftrace_ops. Then when it gets called, if it has more than one registered function, it needs to iterate over the list? -- Steve > > Or, maybe we can make the common callback to find the previous ret entry on > the ret_stack and reuse it. (In this case we don't need loop on each > fgraph_array entry)
