Re: [patch 1/4] taskstats: Introduce "struct cdata"

[Oleg Nesterov <oleg@redhat.com>]

On 11/19, Michael Holzheu wrote:
>
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> This patch introduces a new structure "struct cdata" that is used to
> store cumulative resource counters for dead child processes and threads.
>
> Note that there is one asymmetry:
> For "struct task_io_accounting" (ioc) there is no extra accounting field for
> dead threads. One field is used for both, dead processes and threads.
>
> This patch introduces no functional change.
>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> ---
>  fs/binfmt_elf.c           |    4 +-
>  fs/exec.c                 |    2 -
>  fs/proc/array.c           |   16 ++++----
>  include/linux/sched.h     |   22 +++++++----
>  kernel/exit.c             |   86 ++++++++++++++++++++++++----------------------
>  kernel/posix-cpu-timers.c |   12 +++---
>  kernel/sys.c              |   44 ++++++++++++-----------
>  7 files changed, 100 insertions(+), 86 deletions(-)

Looks good. In fact, to me it looks like a cleanup.

But. You seem to forgot to change kernel/signal.c, no?

And cosmetic nit,

>  void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
>  {
> -	struct signal_struct *sig = tsk->signal;
> +	struct cdata *tcd = &tsk->signal->cdata_threads;
>  	struct task_struct *t;
>
> -	times->utime = sig->utime;
> -	times->stime = sig->stime;
> -	times->sum_exec_runtime = sig->sum_sched_runtime;
> +	times->utime = tcd->utime;
> +	times->stime = tcd->stime;
> +	times->sum_exec_runtime = tsk->signal->sum_sched_runtime;

Feel free to ignore, but I don't understand why you removed "sig".
Afaics,

	-     times->utime = sig->utime;
	-     times->stime = sig->stime;
	+     times->utime = sig->cdata_threads->utime;
	+     times->stime = sig->cdata_threads->stime;

looks a bit better.

Oleg.