On Tue, 13 Aug 2002, Linus Torvalds wrote:
> > it - this is not really a clone() property but an exit-signalling
> > property.
>
> Right. I think that it makes more sense to do it that way. Clearly the
> parent doesn't care about the exit if the signal is zero.
the attached patch implements this (it's ontop of the SETTLS/SETTID patch
for sched.h conflict reasons), i've tested it with signal 0 threads and it
appears to work fine. (I have not tested kmod yet - that comes next.)
and looks pretty straightforward - !current->exit_signal is a good and
natural test.
Ingo
--- linux/kernel/exit.c.orig Tue Aug 13 21:01:50 2002
+++ linux/kernel/exit.c Tue Aug 13 21:49:35 2002
@@ -56,10 +56,13 @@
static void release_task(struct task_struct * p)
{
- if (p == current)
+ if (p == current && p->exit_signal)
+ BUG();
+ if (p->state != TASK_ZOMBIE)
BUG();
#ifdef CONFIG_SMP
- wait_task_inactive(p);
+ if (p != current)
+ wait_task_inactive(p);
#endif
atomic_dec(&p->user->processes);
security_ops->task_free_security(p);
@@ -67,10 +70,12 @@
unhash_process(p);
release_thread(p);
- 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);
+ 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);
}
@@ -479,14 +484,15 @@
write_lock_irq(&tasklist_lock);
current->state = TASK_ZOMBIE;
- do_notify_parent(current, current->exit_signal);
+ if (current->exit_signal)
+ do_notify_parent(current, current->exit_signal);
while ((p = eldest_child(current))) {
list_del_init(&p->sibling);
p->ptrace = 0;
p->parent = p->real_parent;
list_add_tail(&p->sibling,&p->parent->children);
- if (p->state == TASK_ZOMBIE)
+ if (p->state == TASK_ZOMBIE && p->exit_signal)
do_notify_parent(p, p->exit_signal);
/*
* process group orphan check
@@ -555,6 +561,9 @@
tsk->exit_code = code;
exit_notify();
+ preempt_disable();
+ if (!current->exit_signal)
+ release_task(current);
schedule();
BUG();
/*
--- linux/kernel/signal.c.orig Tue Aug 13 21:02:04 2002
+++ linux/kernel/signal.c Tue Aug 13 21:48:01 2002
@@ -768,12 +768,14 @@
/*
* Let a parent know about a status change of a child.
*/
-
void do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
int why, status;
+ if (!sig || !tsk->exit_signal)
+ BUG();
+
info.si_signo = sig;
info.si_errno = 0;
info.si_pid = tsk->pid;
@@ -823,9 +825,11 @@
void
notify_parent(struct task_struct *tsk, int sig)
{
- read_lock(&tasklist_lock);
- do_notify_parent(tsk, sig);
- read_unlock(&tasklist_lock);
+ if (sig != -1) {
+ read_lock(&tasklist_lock);
+ do_notify_parent(tsk, sig);
+ read_unlock(&tasklist_lock);
+ }
}
#ifndef HAVE_ARCH_GET_SIGNAL_TO_DELIVER
--- linux/kernel/fork.c.orig Tue Aug 13 21:02:04 2002
+++ linux/kernel/fork.c Tue Aug 13 21:45:14 2002
@@ -50,6 +50,31 @@
rwlock_t tasklist_lock __cacheline_aligned = RW_LOCK_UNLOCKED; /* outer */
+/*
+ * A per-CPU task cache - this relies on the fact that
+ * the very last portion of sys_exit() is executed with
+ * preemption turned off.
+ */
+static task_t *task_cache[NR_CPUS] __cacheline_aligned;
+
+void __put_task_struct(struct task_struct *tsk)
+{
+ if (tsk != current) {
+ free_thread_info(tsk->thread_info);
+ kmem_cache_free(task_struct_cachep,tsk);
+ } else {
+ int cpu = smp_processor_id();
+
+ tsk = task_cache[cpu];
+ if (tsk) {
+ free_thread_info(tsk->thread_info);
+ kmem_cache_free(task_struct_cachep,tsk);
+ }
+ task_cache[cpu] = current;
+ }
+}
+
+/* Protects next_safe and last_pid. */
void add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
{
unsigned long flags;
@@ -123,13 +148,6 @@
return tsk;
}
-void __put_task_struct(struct task_struct *tsk)
-{
- free_thread_info(tsk->thread_info);
- kmem_cache_free(task_struct_cachep,tsk);
-}
-
-/* Protects next_safe and last_pid. */
spinlock_t lastpid_lock = SPIN_LOCK_UNLOCKED;
static int get_pid(unsigned long flags)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:33 EST