added a debugging functionality in system/debugging.c (to check sanity of

run queues) and associated prototype in system.h

kernel/system.h

@@ -62,8 +62,7 @@ _PROTOTYPE( int do_trace, (message *m_ptr) );		/* process tracing */
 #endif
 
 #if ENABLE_K_DEBUGGING 					/* debugging */
-#error Kernel debugging routines are not implemented.
+_PROTOTYPE( void check_runqueues, (char *when) );
-#else
 #endif
 
 _PROTOTYPE( int do_vircopy, (message *m_ptr) );

kernel/system/debugging.c

@@ -6,9 +6,69 @@
 
 #include "../kernel.h"
 #include "../system.h"
+#include "../proc.h"
 
 #if ENABLE_K_DEBUGGING		/* only include code if enabled */
 
+#define PROCLIMIT 10000
+
+PUBLIC void
+check_runqueues(char *when)
+{
+  int q, l = 0;
+  register struct proc *xp;
+
+  for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
+	xp->p_found = 0;
+	if(l++ > PROCLIMIT) {  panic("check error", NO_NUM); }
+  }
+
+  for (q=0; q < NR_SCHED_QUEUES; q++) {
+    if(rdy_head[q] && !rdy_tail[q]) {
+	kprintf("head but no tail: %s", (karg_t) when);
+		 panic("scheduling error", NO_NUM);
+    }
+    if(!rdy_head[q] && rdy_tail[q]) {
+	kprintf("tail but no head: %s", (karg_t) when);
+		 panic("scheduling error", NO_NUM);
+    }
+    if(rdy_tail[q] && rdy_tail[q]->p_nextready != NIL_PROC) {
+	kprintf("tail and tail->next not null; %s", (karg_t) when);
+		 panic("scheduling error", NO_NUM);
+    }
+    for(xp = rdy_head[q]; xp != NIL_PROC; xp = xp->p_nextready) {
+        if (!xp->p_ready) {
+		kprintf("scheduling error: unready on runq: %s\n", (karg_t) when);
+		
+  		panic("found unready process on run queue", NO_NUM);
+        }
+        if(xp->p_priority != q) {
+		kprintf("scheduling error: wrong priority: %s\n", (karg_t) when);
+		
+		panic("wrong priority", NO_NUM);
+	}
+	if(xp->p_found) {
+		kprintf("scheduling error: double scheduling: %s\n", (karg_t) when);
+		panic("proc more than once on scheduling queue", NO_NUM);
+	}
+	xp->p_found = 1;
+	if(xp->p_nextready == NIL_PROC && rdy_tail[q] != xp) {
+		kprintf("scheduling error: last element not tail: %s\n", (karg_t) when);
+		panic("scheduling error", NO_NUM);
+	}
+	if(l++ > PROCLIMIT) panic("loop in schedule queue?", NO_NUM);
+    }
+  }	
+
+  for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
+	if(isalivep(xp) && xp->p_ready && !xp->p_found) {
+		kprintf("scheduling error: ready not on queue: %s\n", (karg_t) when);
+		panic("ready proc not on scheduling queue", NO_NUM);
+		if(l++ > PROCLIMIT) { panic("loop in proc.t?", NO_NUM); }
+	}
+  }
+}
+
 /*==========================================================================*
  *				do_debug 				    *
  *==========================================================================*/