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signal: re-add dead task accumulation stats.

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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>
This commit is contained in:
Peter Zijlstra 2009-02-05 12:24:15 +01:00 committed by Ingo Molnar
parent 83895147b7
commit 32bd671d6c
4 changed files with 18 additions and 6 deletions
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10
include/linux/sched.h
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@ -559,7 +559,7 @@ struct signal_struct {
* Live threads maintain their own counters and add to these * Live threads maintain their own counters and add to these
* in __exit_signal, except for the group leader. * in __exit_signal, except for the group leader.
*/ */
cputime_t cutime, cstime; cputime_t utime, stime, cutime, cstime;
cputime_t gtime; cputime_t gtime;
cputime_t cgtime; cputime_t cgtime;
unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw; unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
@ -567,6 +567,14 @@ struct signal_struct {
unsigned long inblock, oublock, cinblock, coublock; unsigned long inblock, oublock, cinblock, coublock;
struct task_io_accounting ioac; struct task_io_accounting ioac;
/*
* Cumulative ns of schedule CPU time fo dead threads in the
* group, not including a zombie group leader, (This only differs
* from jiffies_to_ns(utime + stime) if sched_clock uses something
* other than jiffies.)
*/
unsigned long long sum_sched_runtime;
/* /*
* We don't bother to synchronize most readers of this at all, * We don't bother to synchronize most readers of this at all,
* because there is no reader checking a limit that actually needs * because there is no reader checking a limit that actually needs

3
kernel/exit.c
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@ -118,6 +118,8 @@ static void __exit_signal(struct task_struct *tsk)
* We won't ever get here for the group leader, since it * We won't ever get here for the group leader, since it
* will have been the last reference on the signal_struct. * will have been the last reference on the signal_struct.
*/ */
sig->utime = cputime_add(sig->utime, task_utime(tsk));
sig->stime = cputime_add(sig->stime, task_stime(tsk));
sig->gtime = cputime_add(sig->gtime, task_gtime(tsk)); sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
sig->min_flt += tsk->min_flt; sig->min_flt += tsk->min_flt;
sig->maj_flt += tsk->maj_flt; sig->maj_flt += tsk->maj_flt;
@ -126,6 +128,7 @@ static void __exit_signal(struct task_struct *tsk)
sig->inblock += task_io_get_inblock(tsk); sig->inblock += task_io_get_inblock(tsk);
sig->oublock += task_io_get_oublock(tsk); sig->oublock += task_io_get_oublock(tsk);
task_io_accounting_add(&sig->ioac, &tsk->ioac); task_io_accounting_add(&sig->ioac, &tsk->ioac);
sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
sig = NULL; /* Marker for below. */ sig = NULL; /* Marker for below. */
} }

3
kernel/fork.c
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@ -851,13 +851,14 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->tty_old_pgrp = NULL; sig->tty_old_pgrp = NULL;
sig->tty = NULL; sig->tty = NULL;
sig->cutime = sig->cstime = cputime_zero; sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
sig->gtime = cputime_zero; sig->gtime = cputime_zero;
sig->cgtime = cputime_zero; sig->cgtime = cputime_zero;
sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0;
task_io_accounting_init(&sig->ioac); task_io_accounting_init(&sig->ioac);
sig->sum_sched_runtime = 0;
taskstats_tgid_init(sig); taskstats_tgid_init(sig);
task_lock(current->group_leader); task_lock(current->group_leader);

8
kernel/signal.c
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@ -1367,7 +1367,6 @@ int do_notify_parent(struct task_struct *tsk, int sig)
struct siginfo info; struct siginfo info;
unsigned long flags; unsigned long flags;
struct sighand_struct *psig; struct sighand_struct *psig;
struct task_cputime cputime;
int ret = sig; int ret = sig;
BUG_ON(sig == -1); 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; info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock(); rcu_read_unlock();
thread_group_cputime(tsk, &cputime); info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
info.si_utime = cputime_to_jiffies(cputime.utime); tsk->signal->utime));
info.si_stime = cputime_to_jiffies(cputime.stime); info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
tsk->signal->stime));
info.si_status = tsk->exit_code & 0x7f; info.si_status = tsk->exit_code & 0x7f;
if (tsk->exit_code & 0x80) if (tsk->exit_code & 0x80)