Re: [PATCH 3/3] ftrace: trace single pid for function graph tracer

From: Eric W. Biederman
Date: Wed Dec 03 2008 - 18:46:40 EST

Steven Rostedt <rostedt@xxxxxxxxxxx> writes:

>> > # echo $$ > /debugfs/tracing/set_ftrace_pid
>> > # echo function_graph > /debugfs/tracing/current_tracer
>> >
>> > Will cause only the current task to be traced. Note, the trace flags are
>> > also inherited by child processes, so the children of the shell
>> > will also be traced.
>> Where did we end up on the pids-arent-unique issue? Gave up?
> Nah, patch 2 opens the door for a solution. I'm just pawning the work off
> to the container folks ;-)

The way patch 2 uses pids is just stupid. It has nothing to do with
pids aren't unique. You do a full walk of the process list instead
of using the hash table.

It makes me think that task->pid really should go away because with it
there people don't bother to look and see how things normally work.

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