2 * Copyright (c) 1996 Regents of the University of Michigan.
5 * Redistribution and use in source and binary forms are permitted
6 * provided that this notice is preserved and that due credit is given
7 * to the University of Michigan at Ann Arbor. The name of the University
8 * may not be used to endorse or promote products derived from this
9 * software without specific prior written permission. This software
10 * is provided ``as is'' without express or implied warranty.
14 * tsleep.c - allow a thread to sleep without putting the whole process
15 * (e.g. pod under lwp) to sleep. Contains platform-specific code to
18 * Under non-preemptive threads packages like SunOS lwp, tsleep() adds
19 * the thread to a list of sleepers. The lwp_scheduler process takes
20 * care of resuming suspended threads.
22 * Under a fully-preemptive threads package, like Solaris threads,
23 * tsleep just calls sleep(), and there is no scheduler thread. Life
24 * is so much simpler...
35 #if defined( HAVE_LWP )
37 extern stkalign_t *get_stack( int * );
38 extern void free_stack( int );
50 if ( lwp_self( &mylwp ) < 0 ) {
55 mon_enter( &sglob->tsl_mon );
56 if ( sglob->tsl_list != NULL ) {
57 for ( t = sglob->tsl_list; t != NULL; t = t->tl_next ) {
58 if ( SAMETHREAD( t->tl_tid, mylwp )) {
59 /* We're already sleeping? */
60 t->tl_wake = now + (time_t) interval;
61 mon_exit( &sglob->tsl_mon );
67 nt = (tl_t *) malloc( sizeof( tl_t ));
69 nt->tl_next = sglob->tsl_list;
70 nt->tl_wake = now + (time_t) interval;
73 mon_exit( &sglob->tsl_mon );
79 * The lwp_scheduler thread periodically checks to see if any threads
80 * are due to be resumed. If there are, it resumes them. Otherwise,
81 * it computes the lesser of ( 1 second ) or ( the minimum time until
82 * a thread need to be resumed ) and puts itself to sleep for that amount
91 struct timeval interval;
94 while ( !sglob->slurpd_shutdown ) {
95 mon_enter( &sglob->tsl_mon );
98 if ( sglob->tsl_list != NULL ) {
99 for ( t = sglob->tsl_list; t != NULL; t = t->tl_next ) {
100 if (( t->tl_wake > 0L ) && ( t->tl_wake < now )) {
101 lwp_resume( t->tl_tid );
104 if (( t->tl_wake > now ) && ( t->tl_wake < min )) {
109 mon_exit( &sglob->tsl_mon );
110 interval.tv_usec = 0L;
112 interval.tv_sec = 1L;
114 interval.tv_sec = min;
116 lwp_sleep( &interval );
118 mon_enter( &sglob->tsl_mon );
119 for ( t = sglob->tsl_list; t != NULL; t = t->tl_next ) {
120 lwp_resume( t->tl_tid );
122 mon_exit( &sglob->tsl_mon );
123 free_stack( stackno );
128 * Create the lwp_scheduler thread.
131 start_lwp_scheduler()
137 if (( stack = get_stack( &stackno )) == NULL ) {
140 lwp_create( &tid, lwp_scheduler, MINPRIO, 0, stack, 1, stackno );
145 #else /* !HAVE_LWP */
148 * Here we assume we have fully preemptive threads, and that sleep()
149 * does the right thing.
158 #endif /* !HAVE_LWP */