Restore the old way of dispatching dead procs through idle proc.

The new way needs more thought.

5 files changed, 34 insertions, 27 deletions

diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 570aa737f2f..4c6f30cbdf8 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exit.c,v 1.179 2019/11/02 05:31:20 visa Exp $	*/
+/*	$OpenBSD: kern_exit.c,v 1.180 2019/11/04 18:06:02 visa Exp $	*/
 /*	$NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $	*/
 
 /*
@@ -367,27 +367,21 @@ struct mutex deadproc_mutex =
 struct proclist deadproc = LIST_HEAD_INITIALIZER(deadproc);
 
 /*
- * Move dead procs from the CPU's local list to the reaper list and
- * wake up the reaper.
+ * We are called from cpu_exit() once it is safe to schedule the
+ * dead process's resources to be freed.
  *
- * This is called once it is safe to free the resources of dead processes.
+ * NOTE: One must be careful with locking in this routine.  It's
+ * called from a critical section in machine-dependent code, so
+ * we should refrain from changing any interrupt state.
+ *
+ * We lock the deadproc list, place the proc on that list (using
+ * the p_hash member), and wake up the reaper.
  */
 void
-dispatch_deadproc(void)
+exit2(struct proc *p)
 {
-	struct proc *dead;
-	struct schedstate_percpu *spc = &curcpu()->ci_schedstate;
-
-	if (LIST_EMPTY(&spc->spc_deadproc))
-		return;
-
-	KERNEL_ASSERT_UNLOCKED();
-
 	mtx_enter(&deadproc_mutex);
-	while ((dead = LIST_FIRST(&spc->spc_deadproc)) != NULL) {
-		LIST_REMOVE(dead, p_hash);
-		LIST_INSERT_HEAD(&deadproc, dead, p_hash);
-	}
+	LIST_INSERT_HEAD(&deadproc, p, p_hash);
 	mtx_leave(&deadproc_mutex);
 
 	wakeup(&deadproc);
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c
index 94ebd833ab1..46de8fa7800 100644
--- a/sys/kern/kern_sched.c
+++ b/sys/kern/kern_sched.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sched.c,v 1.61 2019/11/02 05:31:20 visa Exp $	*/
+/*	$OpenBSD: kern_sched.c,v 1.62 2019/11/04 18:06:03 visa Exp $	*/
 /*
  * Copyright (c) 2007, 2008 Artur Grabowski <art@openbsd.org>
  *
@@ -159,10 +159,17 @@ sched_idle(void *v)
 
 	while (1) {
 		while (!cpu_is_idle(curcpu())) {
+			struct proc *dead;
+
 			SCHED_LOCK(s);
 			p->p_stat = SSLEEP;
 			mi_switch();
 			SCHED_UNLOCK(s);
+
+			while ((dead = LIST_FIRST(&spc->spc_deadproc))) {
+				LIST_REMOVE(dead, p_hash);
+				exit2(dead);
+			}
 		}
 
 		splassert(IPL_NONE);
@@ -197,7 +204,7 @@ sched_idle(void *v)
  * and waking up the reaper without risking having our address space and
  * stack torn from under us before we manage to switch to another proc.
  * Therefore we have a per-cpu list of dead processes where we put this
- * proc. We move the list to the reaper list after context switch.
+ * proc and have idle clean up that list and move it to the reaper list.
  * All this will be unnecessary once we can bind the reaper this cpu
  * and not risk having it switch to another in case it sleeps.
  */
@@ -205,8 +212,14 @@ void
 sched_exit(struct proc *p)
 {
 	struct schedstate_percpu *spc = &curcpu()->ci_schedstate;
+	struct timespec ts;
+	struct proc *idle;
 	int s;
 
+	nanouptime(&ts);
+	timespecsub(&ts, &spc->spc_runtime, &ts);
+	timespecadd(&p->p_rtime, &ts, &p->p_rtime);
+
 	LIST_INSERT_HEAD(&spc->spc_deadproc, p, p_hash);
 
 #ifdef MULTIPROCESSOR
@@ -216,8 +229,10 @@ sched_exit(struct proc *p)
 #endif
 
 	SCHED_LOCK(s);
-	mi_switch();
-	panic("mi_switch returned");
+	idle = spc->spc_idleproc;
+	idle->p_stat = SRUN;
+	cpu_switchto(NULL, idle);
+	panic("cpu_switchto returned");
 }
 
 /*
diff --git a/sys/kern/sched_bsd.c b/sys/kern/sched_bsd.c
index 8f988ae7c57..5219a9121b6 100644
--- a/sys/kern/sched_bsd.c
+++ b/sys/kern/sched_bsd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sched_bsd.c,v 1.58 2019/11/02 05:31:20 visa Exp $	*/
+/*	$OpenBSD: sched_bsd.c,v 1.59 2019/11/04 18:06:03 visa Exp $	*/
 /*	$NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $	*/
 
 /*-
@@ -413,7 +413,6 @@ mi_switch(void)
 
 	SCHED_ASSERT_UNLOCKED();
 
-	dispatch_deadproc();
 	smr_idle();
 
 	/*
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 066a0f98c11..5830b02e13f 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.277 2019/11/02 05:31:20 visa Exp $	*/
+/*	$OpenBSD: proc.h,v 1.278 2019/11/04 18:06:03 visa Exp $	*/
 /*	$NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $	*/
 
 /*-
@@ -567,8 +567,8 @@ void	setrunnable(struct proc *);
 void	endtsleep(void *);
 void	unsleep(struct proc *);
 void	reaper(void *);
-void	dispatch_deadproc(void);
 void	exit1(struct proc *, int, int);
+void	exit2(struct proc *);
 int	dowait4(struct proc *, pid_t, int *, int, struct rusage *,
 	    register_t *);
 void	cpu_fork(struct proc *_curp, struct proc *_child, void *_stack,
diff --git a/sys/sys/syscall_mi.h b/sys/sys/syscall_mi.h
index 571447f790e..1e071933349 100644
--- a/sys/sys/syscall_mi.h
+++ b/sys/sys/syscall_mi.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syscall_mi.h,v 1.22 2019/11/02 05:31:20 visa Exp $	*/
+/*	$OpenBSD: syscall_mi.h,v 1.23 2019/11/04 18:06:03 visa Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -138,7 +138,6 @@ mi_child_return(struct proc *p)
 	KERNEL_UNLOCK();
 #endif
 
-	dispatch_deadproc();
 	userret(p);
 
 #ifdef KTRACE