Re: Add all thread stats for TASKSTATS_CMD_ATTR_TGID (v5)

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 18 Sep 2007 00:23:39 +0200 Guillaume Chazarain <guichaz@yahoo.fr> wrote:

> TASKSTATS_CMD_ATTR_TGID used to return only the delay accounting stats, not
> the basic and extended accounting.  With this patch,
> TASKSTATS_CMD_ATTR_TGID also aggregates the accounting info for all threads
> of a thread group.  This makes TASKSTATS_CMD_ATTR_TGID usable in a similar
> fashion to TASKSTATS_CMD_ATTR_PID, for commands like iotop -P
> (http://guichaz.free.fr/misc/iotop.py).

This patch conflicts somewhat with
add-scaled-time-to-taskstats-based-process-accounting.patch

I fixed it up like this:

void bacct_add_tsk(struct taskstats *stats, struct task_struct *task)
{
	if (task->flags & PF_SUPERPRIV)
		stats->ac_flag |= ASU;
	if (task->flags & PF_DUMPCORE)
		stats->ac_flag |= ACORE;
	if (task->flags & PF_SIGNALED)
		stats->ac_flag |= AXSIG;
	if (thread_group_leader(task) && (task->flags & PF_FORKNOEXEC))
		/*
		 * Threads are created by do_fork() and don't exec but not in
		 * the AFORK sense, as the latter involves fork(2).
		 */
		stats->ac_flag |= AFORK;

	stats->ac_utimescaled +=
		cputime_to_msecs(task->utimescaled) * USEC_PER_MSEC;
	stats->ac_stimescaled +=
		cputime_to_msecs(task->stimescaled) * USEC_PER_MSEC;
	stats->ac_utime	 += cputime_to_msecs(task->utime) * USEC_PER_MSEC;
	stats->ac_stime	 += cputime_to_msecs(task->stime) * USEC_PER_MSEC;
	stats->ac_minflt += task->min_flt;
	stats->ac_majflt += task->maj_flt;
}

(note the s/=/+=/ in there) but it all needs reviewing and checking and
testing please.