Re: [PATCH 3/3] ftrace: add ability to only trace swapper tasks

From: Steven Rostedt
Date: Thu Dec 04 2008 - 16:56:54 EST

On Thu, 4 Dec 2008, Eric W. Biederman wrote:
> Right. I simply meant most of the
> if (likely(p->pid)) conditional except for the counts is pretty much a don't
> care. Keeping the idle tasks off of the process list and out of the counts
> is useful.
> For this particular case what problem did you see with calling attach_pid
> with PIDTYPE_PID on init_struct_pid?

On boot up, the CPU 0 idle task is attached to init_struct_pid, and not
the others. If you do a "attach_pid" on the next idle task that is created,
it will become the attched process, bumping off CPU 0's idle task from the

When doing the code you suggested, I end up with only marking the last
idle task to be created.

-- Steve

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