Remove the concept of thread priorities from empthread.h. Only LWP

supports priorities.  Update synchronization used to rely on them,
which naturally worked only with LWP (#1504036).  With that fixed, no
uses of priorities remained, but a minor bug did: players could starve
out threads with priorities below PP_PLAYER, i.e. delete_lostitems()
and player_kill_idle().  Closes #1458175:
(empth_create): Remove parameter prio.  Callers changed.  Also gets
rid of misleading comments in pthread.c and ntthread.c.
(PP_MAIN, PP_UPDATE, PP_SHUTDOWN, PP_SCHED, PP_TIMESTAMP, PP_PLAYER)
(PP_ACCEPT, PP_KILLIDLE): Remove.
(empth_init, empth_create) [EMPTH_LWP]: Pass priority 1.

include/empthread.h

@@ -51,18 +51,6 @@
 
 #include <time.h>
 
-/* thread priorities */
-enum {
-    PP_MAIN	 = 7,
-    PP_UPDATE	 = 6,
-    PP_SHUTDOWN	 = 5,
-    PP_SCHED	 = 4,
-    PP_TIMESTAMP = 2,
-    PP_PLAYER	 = 3,
-    PP_ACCEPT	 = 3,
-    PP_KILLIDLE	 = 2
-};
-
 #ifdef EMPTH_LWP
 #include "lwp.h"
 
@@ -123,7 +111,6 @@ int empth_init(void **ctx, int flags);
 
 /*
  * Create a new thread.
- * PRIO is the scheduling priority.
  * ENTRY is the entry point.  It will be called with argument UD.
  * Thread stack is at least SIZE bytes.
  * FLAGS should be the same as were passed to empth_init(), or zero.
@@ -134,7 +121,7 @@ int empth_init(void **ctx, int flags);
  * Yield the processor.
  * Return the thread, or NULL on error.
  */
-empth_t *empth_create(int prio, void (*entry)(void *),
+empth_t *empth_create(void (*entry)(void *),
 		      int size, int flags, char *name, void *ud);
 
 /*

src/lib/empthread/lwp.c

@@ -54,18 +54,18 @@ empth_init(void **ctx, int flags)
     sigaddset(&set, SIGHUP);
     sigaddset(&set, SIGINT);
     sigaddset(&set, SIGTERM);
-    lwpInitSystem(PP_MAIN, ctx, flags, &set);
+    lwpInitSystem(1, ctx, flags, &set);
     return 0;
 }
 
 
 empth_t *
-empth_create(int prio, void (*entry)(void *), int size, int flags,
+empth_create(void (*entry)(void *), int size, int flags,
 	     char *name, void *ud)
 {
     if (!flags)
 	flags = empth_flags;
-    return lwpCreate(prio, entry, size, flags, name, 0, 0, ud);
+    return lwpCreate(1, entry, size, flags, name, 0, 0, ud);
 }
 
 empth_t *

src/lib/empthread/ntthread.c

@@ -418,7 +418,6 @@ empth_init(void **ctx_ptr, int flags)
  *
  * Create a new thread.
  *
- * prio  - priority, not particularly useful in our context.
  * entry - entry point function for thread.
  * size  - stack size.
  * flags - debug control.
@@ -429,7 +428,7 @@ empth_init(void **ctx_ptr, int flags)
  *         It is also passed to the entry function...
  */
 empth_t *
-empth_create(int prio, void (*entry)(void *), int size, int flags,
+empth_create(void (*entry)(void *), int size, int flags,
 	     char *name, void *ud)
 {
     empth_t *pThread = NULL;

src/lib/empthread/pthread.c

@@ -180,14 +180,8 @@ empth_init(void **ctx_ptr, int flags)
 }
 
 
-/*
- * prio can be used for setting scheeduling policy but...
- * it seems to be optional in POSIX threads and Solaris
- * for example just ignores it.
- * More then that priority is not needed even in lwp threads.
- */
 empth_t *
-empth_create(int prio, void (*entry)(void *), int size, int flags,
+empth_create(void (*entry)(void *), int size, int flags,
 	     char *name, void *ud)
 {
     pthread_t t;

src/lib/player/accept.c

@@ -224,7 +224,6 @@ player_accept(void *unused)
 /* budget */  + MAX(WORLD_X * WORLD_Y / 2 * sizeof(int) * 7,
 /* power */ MAXNOC * sizeof(struct powstr));
 	sprintf(buf, "Player (fd #%d)", ns);
-	empth_create(PP_PLAYER, player_login, stacksize,
-		     0, buf, np);
+	empth_create(player_login, stacksize, 0, buf, np);
     }
 }

src/server/main.c

@@ -331,12 +331,9 @@ start_server(int flags)
     if (journal_startup() < 0)
 	exit(1);
 
-    empth_create(PP_ACCEPT, player_accept, (50 * 1024), flags,
-		 "AcceptPlayers", 0);
-    empth_create(PP_KILLIDLE, player_kill_idle, (50 * 1024), flags,
-		 "KillIdle", 0);
-    empth_create(PP_TIMESTAMP, delete_lostitems, (50 * 1024), flags,
-		 "DeleteItems", 0);
+    empth_create(player_accept, 50 * 1024, flags, "AcceptPlayers", 0);
+    empth_create(player_kill_idle, 50 * 1024, flags, "KillIdle", 0);
+    empth_create(delete_lostitems, 50 * 1024, flags, "DeleteItems", 0);
 
     market_init();
     update_init();

src/server/marketup.c

@@ -71,7 +71,6 @@ market_init(void)
     dp = player_new(-1);
     if (!dp)
 	exit_nomem();
-    if (!empth_create(PP_UPDATE, market_update, 50 * 1024, 0,
-		      "MarketUpdate", dp))
+    if (!empth_create(market_update, 50 * 1024, 0, "MarketUpdate", dp))
 	exit_nomem();
 }

src/server/shutdown.c

@@ -65,7 +65,7 @@ shutdown_initiate(int mins_from_now)
 		mins_from_now);
 	/* FIXME wake up shutdown_sequence() */
     } else {
-	if (!empth_create(PP_SHUTDOWN, shutdown_sequence, 50 * 1024, 0,
+	if (!empth_create(shutdown_sequence, 50 * 1024, 0,
 			  "shutdownSeq", NULL))
 	    return -1;
     }

src/server/update.c

@@ -85,7 +85,7 @@ update_init(void)
     stacksize = 100000 +
 /* finish_sects */ WORLD_X * WORLD_Y * (2 * sizeof(double) +
 					sizeof(char *));
-    update_thread = empth_create(PP_UPDATE, update_sched, stacksize, 0,
+    update_thread = empth_create(update_sched, stacksize, 0,
 				 "Update", dp);
     if (!update_thread)
 	exit_nomem();