On 09/20, Balbir Singh wrote:
>
> Andrew Morton wrote:
> > On Tue, 18 Sep 2007 00:23:39 +0200 Guillaume Chazarain <[email protected]> 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.
>
> Andrew,
>
> Thanks for reviewing the patchset, this patch is on my review and test
> queue (which has gotten rather long of late). I'll test it further and
> get back.
I still think this version is very wrong. It makes the ->signal->stats
absolutely meaningless. Quoting myself:
On 09/18, Guillaume Chazarain wrote:
>
> @@ -508,7 +543,7 @@ void taskstats_exit(struct task_struct *
> if (!stats)
> goto err;
>
> - memcpy(stats, tsk->signal->stats, sizeof(*stats));
> + fill_tgid(tsk->pid, tsk, stats);
No, no, this is wrong.
tsk->signal->stats contains the accumulated info about the already exited
threads, we shouldn't throw it out.
Also, fill_tgid() doesn't make sense here, current is the last live sub-thread.
Oleg.
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