ref: cb5057c6b3f549328a09fb08b300a0f74f671520
dir: /os/port/taslock.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" static void lockloop(Lock *l, ulong pc) { setpanic(); print("lock loop 0x%lux key 0x%lux pc 0x%lux held by pc 0x%lux\n", l, l->key, pc, l->pc); panic("lockloop"); } void lock(Lock *l) { int i; ulong pc; pc = getcallerpc(&l); if(up == 0) { if (_tas(&l->key) != 0) { for(i=0; ; i++) { if(_tas(&l->key) == 0) break; if (i >= 1000000) { lockloop(l, pc); break; } } } l->pc = pc; return; } for(i=0; ; i++) { if(_tas(&l->key) == 0) break; if (i >= 1000) { lockloop(l, pc); break; } if(conf.nmach == 1 && up->state == Running && islo()) { up->pc = pc; sched(); } } l->pri = up->pri; up->pri = PriLock; l->pc = pc; } void ilock(Lock *l) { ulong x, pc; int i; pc = getcallerpc(&l); x = splhi(); for(;;) { if(_tas(&l->key) == 0) { l->sr = x; l->pc = pc; return; } if(conf.nmach < 2) panic("ilock: no way out: pc 0x%lux: lock 0x%lux held by pc 0x%lux", pc, l, l->pc); for(i=0; ; i++) { if(l->key == 0) break; clockcheck(); if (i > 100000) { lockloop(l, pc); break; } } } } int canlock(Lock *l) { if(_tas(&l->key)) return 0; if(up){ l->pri = up->pri; up->pri = PriLock; } l->pc = getcallerpc(&l); return 1; } void unlock(Lock *l) { int p; if(l->key == 0) print("unlock: not locked: pc %lux\n", getcallerpc(&l)); p = l->pri; l->pc = 0; l->key = 0; coherence(); if(up){ up->pri = p; if(up->state == Running && anyhigher()) sched(); } } void iunlock(Lock *l) { ulong sr; if(l->key == 0) print("iunlock: not locked: pc %lux\n", getcallerpc(&l)); sr = l->sr; l->pc = 0; l->key = 0; coherence(); splxpc(sr); }