1996/0522/port/taslock.c (diff list | history)

1996/0517/sys/src/9/port/taslock.c:13,53 – 1996/0522/sys/src/9/port/taslock.c:13,72 (short | long | prev | next)
1995/1030		dumpaproc(up); }
1996/0522		#define LOCKLOOP 100000000 /* to detect a lock loop */ #define SPINLOOP 10000000 /* to keep tas's off the bus */
1995/1030		void
1992/0222		lock(Lock *l) {
1996/0511		int pri, i; ulong pc;
1996/0522		int i, pri, spins; ulong pc, pid;
1995/1009		pc = getcallerpc(l);
1996/0522		if(up){ pid = up->pid; pri = up->priority; } else { pid = 0; pri = 0; }
1995/1009
1996/0511		if(up == 0) { for(i=0; i<1000000; i++) if(tas(&l->key) == 0){ l->pc = pc;
1996/0516		l->pri = 0;
1996/0511		return; } lockloop(l, pc);
1996/0522		/* quick try, it might work */ if(tas(&l->key) == 0){ l->pc = pc; l->pid = pid; l->pri = pri;
1995/0110		return;
1995/1009		}
1995/0108
1996/0516		/* priority interacts with code in ready() in proc.c */
1996/0511		pri = up->priority;
1996/0522		spins = 0; for(;;){ i = 0; while(l->key) if(i++ > SPINLOOP){ /* look for lock loops */ if(spins++ > LOCKLOOP/SPINLOOP){ spins = 0; lockloop(l, pc); }
1996/0511
1996/0517		for(i=0; i<1000000; i++){
1996/0516		up->lockpri = l->pri; /* assume priority of process holding lock */
1996/0522		/* possible priority inversion, try switching priority */ if(up && up->state == Running) if(getstatus()&IE) { print("priority inversion\n"); up->lockpri = l->pri; sched(); } }
1995/1009		if(tas(&l->key) == 0){
1996/0511		l->pri = pri;
1996/0516		up->lockpri = 0; /* back to normal priority */
1995/1009		l->pc = pc;
1996/0522		l->pid = pid; l->pri = pri; up->lockpri = 0;
1995/0108		return;
1995/1009		}
1996/0511		if(conf.nmach == 1 && up->state == Running && (getstatus()&IE)) sched();
1995/0108		}
1996/0511		lockloop(l, pc);
1996/0516		up->lockpri = 0; /* back to normal priority */
1995/0110		}
1995/0108
1995/0110		void
1996/0517/sys/src/9/port/taslock.c:64,69 – 1996/0522/sys/src/9/port/taslock.c:83,89
1995/0110		l->sr = x;
1995/1009		l->pc = pc;
1995/1030		l->pid = pid;
1996/0522		l->pri = 0;
1993/1204		return;
1995/0110		}
1996/0517/sys/src/9/port/taslock.c:74,79 – 1996/0522/sys/src/9/port/taslock.c:94,100
1995/0110		l->sr = x;
1995/1009		l->pc = pc;
1995/1030		l->pid = pid;
1996/0522		l->pri = 0;
1992/0222		return;
1995/0110		}
1992/0222		}
1996/0517/sys/src/9/port/taslock.c:82,98 – 1996/0522/sys/src/9/port/taslock.c:103,119
1995/0109		int canlock(Lock *l)
1994/0322		{
1996/0511		int pri;
1995/0110
1996/0516		if(up)
1996/0511		pri = up->priority;
1996/0516		else pri = 0;
1996/0511		if(tas(&l->key)) { l->pc = getcallerpc(l);
1996/0522		if(tas(&l->key))
1996/0511		return 0;
1996/0522		l->pc = getcallerpc(l); if(up){ l->pid = up->pid; l->pri = up->priority; } else { l->pid = 0; l->pri = 0;
1996/0511		} l->pri = pri;
1992/0222		return 1; }
1996/0517/sys/src/9/port/taslock.c:99,106 – 1996/0522/sys/src/9/port/taslock.c:120,127
1992/0222		void unlock(Lock *l) {
1995/1014		l->pc = 0;
1996/0511		l->key = 0;
1996/0522		l->pc = 0;
1996/0516		l->pri = 0;
1994/0322		}
1996/0517/sys/src/9/port/taslock.c:112,116 – 1996/0522/sys/src/9/port/taslock.c:133,138
1994/0322		sr = l->sr;
1995/0110		l->key = 0;
1995/1014		l->pc = 0;
1996/0522		l->pri = 0;
1994/0322		splx(sr);
1992/0222		}