On Fri, 19 Jan 2024 23:43:56 +0900 Masami Hiramatsu (Google) <[email protected]> wrote:
> Thanks for your proposal! > > Generically, I think this type of hack is not good for the tracing > because there are already some ways to do that. e.g. > - Use perf probe to specify dentry->name:string or file->name:string > - Use BTF to specify in the same way (but only for function entry) > And those are more obvious what it does. > > However, if this is implemented in more generic syntax, it will be > acceptable. > For example, type specifying with "arg1:printfmt(%pD)" will be > more generic because it is apparently one of the printfmt and output > string. Or, maybe we can just allow to use ":%pD" as a fetch type > (start with '%' means the printfmt) Yes, I like this idea a lot. Please add the '%' keyword/token to change how to display this in the print format. We may need to add more than one token though. Is that supported? $arg1:u32:%08x or that could also be: $arg1:%08x:u32 That is, the order should not be important. Thoughts? -- Steve > > Also, could you update readme_msg[] in kernel/trace/trace.c if > you add a type, and add a testcase of selftests/ftrace, for this > feature? Documentation should also be updated with more syntax > information.
