On Mon, 26 Feb 2024 08:51:58 +0900 Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote: > On Thu, 8 Feb 2024 21:18:14 +0800 > Huang Yiwei <quic_hyiwei@xxxxxxxxxxx> wrote: > > > Currently ftrace only dumps the global trace buffer on an OOPs. For > > debugging a production usecase, instance trace will be helpful to > > check specific problems since global trace buffer may be used for > > other purposes. > > > > This patch extend the ftrace_dump_on_oops parameter to dump a specific > > or multiple trace instances: > > > > - ftrace_dump_on_oops=0: as before -- don't dump > > - ftrace_dump_on_oops[=1]: as before -- dump the global trace buffer > > on all CPUs > > - ftrace_dump_on_oops=2 or =orig_cpu: as before -- dump the global > > trace buffer on CPU that triggered the oops > > - ftrace_dump_on_oops=<instance_name>: new behavior -- dump the > > tracing instance matching <instance_name> > > - ftrace_dump_on_oops[=2/orig_cpu],<instance1_name>[=2/orig_cpu], > > Would you mean "ftrace_dump_on_oops,<instance1_name>" ? ?? > As far as I can see, it doesn't work. Command line parser requires "=" > for parameter value. Not sure what you mean, but it does work with: ftrace_dump_on_oops=1,foo=2 As well as ftrace_dump_on_oops=foo If you want to dump with an instance, yes you need a '=' sign. > Also, is there any reason to limit the parameter > to 2 or orig_cpu? There's 3 options: 0 = off, 1 = all (default), 2 = orig_cpu I don't see it limited. You don't need the equal sign if you just want the top buffer. > > What about this syntax? > > ftrace_dump_on_oops=<0|1|2|orig_cpu>[,<instance_name>[=<1|2|orig_cpu>][,...] That should work now. But why add the requirement of an '=' as that isn't needed now? That is, the syntax is: ftrace_dump_on_oops[=[<0|1|2|orig_cpu>,][<instance_name>[=<1|2|orig_cpu>][,...]] > > or > > ftrace_dump_on_oops=instance_name[=<1|2|orig_cpu>][,...] This works. > > or > > ftrace_dump_on_oops This works. > > e.g. > "ftrace_dump_on_oops=0,foo=orig_cpu" is equal to "ftrace_dump_on_oops=foo=orig_cpu" > And that does. I think this patch does what you are asking for. -- Steve
