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

From: Steven Rostedt
Date: Wed Dec 03 2008 - 21:29:25 EST

On Wed, 3 Dec 2008, Eric W. Biederman wrote:

> Steven Rostedt <rostedt@xxxxxxxxxxx> writes:
> 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.

The way patch 2 uses the pids is stupid, it was just the easiest way to
implement it correctly ;-) I work with, do it stupid but correct first,
then optimize.

> 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.

This is far from a fast path, and I can easily fix it. The hard work was
the rest of the patch not this part. I even did it stupid knowing that I
would be rewriting it to handle namespaces. I stated that this needed to
be fixed in the patch itself.

One thing I never got an answer for, using the namespace pid path, can I
still select the idle task to trace, i.e. pid == 0.

-- Steve

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