signal: re-add dead task accumulation stats.

We're going to split the process wide cpu accounting into two parts:

 - clocks; which can take all the time they want since they run
           from user context.

 - timers; which need constant time tracing but can affort the overhead
           because they're default off -- and rare.

The clock readout will go back to a full sum of the thread group, for this
we need to re-add the exit stats that were removed in the initial itimer
rework (f06febc9: timers: fix itimer/many thread hang).

Furthermore, since that full sum can be rather slow for large thread groups
and we have the complete dead task stats, revert the do_notify_parent time
computation.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 4 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index b6b36768b758..2a74fe87c0dd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1367,7 +1367,6 @@ int do_notify_parent(struct task_struct *tsk, int sig)
         struct siginfo info;
         unsigned long flags;
         struct sighand_struct *psig;
-        struct task_cputime cputime;
         int ret = sig;
 
         BUG_ON(sig == -1);
@@ -1397,9 +1396,10 @@ int do_notify_parent(struct task_struct *tsk, int sig)
         info.si_uid = __task_cred(tsk)->uid;
         rcu_read_unlock();
 
-        thread_group_cputime(tsk, &cputime);
-        info.si_utime = cputime_to_jiffies(cputime.utime);
-        info.si_stime = cputime_to_jiffies(cputime.stime);
+        info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
+                                tsk->signal->utime));
+        info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
+                                tsk->signal->stime));
 
         info.si_status = tsk->exit_code & 0x7f;
         if (tsk->exit_code & 0x80)