From: Tomas Hruby <tom@minix3.org>
Date: Sat, 10 Apr 2010 15:19:25 +0000 (+0000)
Subject: A simpler test whether to use kernel's default scheduling
X-Git-Tag: v3.1.7~160
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch01.html?a=commitdiff_plain;h=9fdb773cdbdc08b6a53a3feef803f8ef9cf036d5;p=minix.git

A simpler test whether to use kernel's default scheduling

- this is a small addition to the userspace scheduling.
  proc_kernel_scheduler() tests whether to use the default scheduling
  policy in kernel. It is true if the process' scheduler is NULL _or_
  self. Currently none of the tests was complete.
---

diff --git a/kernel/proc.c b/kernel/proc.c
index 7c828d46c..0053e2774 100644
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -129,7 +129,7 @@ not_runnable_pick_new:
 	 * If this process is scheduled by the kernel, we renew it's quantum
 	 * and remove it's RTS_NO_QUANTUM flag.
 	 */
-	if (proc_no_quantum(proc_ptr) && (proc_ptr->p_scheduler == NULL)) {
+	if (proc_no_quantum(proc_ptr) && proc_kernel_scheduler(proc_ptr)) {
 		/* give new quantum */
 		proc_ptr->p_ticks_left = proc_ptr->p_quantum_size;
 		RTS_UNSET(proc_ptr, RTS_NO_QUANTUM);
@@ -1355,14 +1355,14 @@ PRIVATE void notify_scheduler(struct proc *p)
 	 * quantum. This is done by sending a message to the scheduler
 	 * on the process's behalf
 	 */
-	if (p->p_scheduler == p) {
+	if (proc_kernel_scheduler(p)) {
 		/*
-		 * If a scheduler is scheduling itself, and runs out of
-		 * quantum, we don't send a message. The RTS_NO_QUANTUM
-		 * flag will be removed by schedcheck in proc.c.
+		 * If a scheduler is scheduling itself or has no scheduler, and
+		 * runs out of quantum, we don't send a message. The
+		 * RTS_NO_QUANTUM flag will be removed by schedcheck in proc.c.
 		 */
 	}
-	else if (p->p_scheduler != NULL) {
+	else {
 		message m_no_quantum;
 		int err;
 
diff --git a/kernel/proc.h b/kernel/proc.h
index a059ecf70..99e3ec3b7 100644
--- a/kernel/proc.h
+++ b/kernel/proc.h
@@ -148,6 +148,10 @@ struct proc {
 #define proc_no_quantum(p)	((p)->p_rts_flags & RTS_NO_QUANTUM)
 #define proc_ptr_ok(p)		((p)->p_magic == PMAGIC)
 
+/* test whether the process is scheduled by the kernel's default policy  */
+#define proc_kernel_scheduler(p)	((p)->p_scheduler == NULL || \
+					(p)->p_scheduler == (p))
+
 /* Macro to return: on which process is a certain process blocked?
  * return endpoint number (can be ANY) or NONE. It's important to
  * check RTS_SENDING first, and then RTS_RECEIVING, as they could