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Subject[patch] detached-fix-2.5.34-A0, BK-curr

the attached patch fixes three resource accounting related bugs introduced
by detached threads:

- the 'child CPU usage' fields were updated in wait4 until now - this was
slightly buggy for a number of reasons, eg. if the exit_code writout
faults then it's possible to trigger this code multiple times.

- those threads that do not go through wait4 were not properly accounted.

- sched_exit() was incorrectly assuming that current == parent. In the
detached case p->parent is the real parent.

with this patch applied things like 'time' work again for new-style
threaded apps.

Ingo

--- linux/kernel/exit.c.orig Sun Sep 15 10:40:03 2002
+++ linux/kernel/exit.c Sun Sep 15 10:46:11 2002
@@ -71,19 +71,19 @@
write_lock_irq(&tasklist_lock);
__exit_sighand(p);
proc_dentry = __unhash_process(p);
+ p->parent->cutime += p->utime + p->cutime;
+ p->parent->cstime += p->stime + p->cstime;
+ p->parent->cmin_flt += p->min_flt + p->cmin_flt;
+ p->parent->cmaj_flt += p->maj_flt + p->cmaj_flt;
+ p->parent->cnswap += p->nswap + p->cnswap;
+ sched_exit(p);
write_unlock_irq(&tasklist_lock);
+
if (unlikely(proc_dentry != NULL)) {
shrink_dcache_parent(proc_dentry);
dput(proc_dentry);
}
-
release_thread(p);
- if (p != current) {
- current->cmin_flt += p->min_flt + p->cmin_flt;
- current->cmaj_flt += p->maj_flt + p->cmaj_flt;
- current->cnswap += p->nswap + p->cnswap;
- sched_exit(p);
- }
put_task_struct(p);
}

@@ -794,8 +794,6 @@
}
goto end_wait4;
case TASK_ZOMBIE:
- current->cutime += p->utime + p->cutime;
- current->cstime += p->stime + p->cstime;
read_unlock(&tasklist_lock);
retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
if (!retval && stat_addr) {
--- linux/kernel/sched.c.orig Sun Sep 15 10:45:24 2002
+++ linux/kernel/sched.c Sun Sep 15 10:45:59 2002
@@ -479,17 +479,17 @@
{
local_irq_disable();
if (p->first_time_slice) {
- current->time_slice += p->time_slice;
- if (unlikely(current->time_slice > MAX_TIMESLICE))
- current->time_slice = MAX_TIMESLICE;
+ p->parent->time_slice += p->time_slice;
+ if (unlikely(p->parent->time_slice > MAX_TIMESLICE))
+ p->parent->time_slice = MAX_TIMESLICE;
}
local_irq_enable();
/*
* If the child was a (relative-) CPU hog then decrease
* the sleep_avg of the parent as well.
*/
- if (p->sleep_avg < current->sleep_avg)
- current->sleep_avg = (current->sleep_avg * EXIT_WEIGHT +
+ if (p->sleep_avg < p->parent->sleep_avg)
+ p->parent->sleep_avg = (p->parent->sleep_avg * EXIT_WEIGHT +
p->sleep_avg) / (EXIT_WEIGHT + 1);
}

-
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