/* * Acquire a usimple_lock. * * MACH_RT: Returns with preemption disabled. Note * that the hw_lock routines are responsible for * maintaining preemption state. */ void usimple_lock( usimple_lock_t l) { int i; unsigned int timeouttb; /* Used to convert time to timebase ticks */ pc_t pc; #if ETAP_LOCK_TRACE etap_time_t start_wait_time; int no_miss_info = 0; #endif /* ETAP_LOCK_TRACE */ #if USLOCK_DEBUG int count = 0; #endif /* USLOCK_DEBUG */ OBTAIN_PC(pc, l); USLDBG(usld_lock_pre(l, pc)); #if ETAP_LOCK_TRACE ETAP_TIME_CLEAR(start_wait_time); #endif /* ETAP_LOCK_TRACE */ while (!hw_lock_try(&l->interlock)) { ETAPCALL(if (no_miss_info++ == 0) start_wait_time = etap_simplelock_miss(l)); while (hw_lock_held(&l->interlock)) { /* * Spin watching the lock value in cache, * without consuming external bus cycles. * On most SMP architectures, the atomic * instruction(s) used by hw_lock_try * cost much, much more than an ordinary * memory read. */ #if USLOCK_DEBUG if (count++ > max_lock_loops #if MACH_KDB && NCPUS > 1 && l != &kdb_lock #endif /* MACH_KDB && NCPUS > 1 */ ) { if (l == &printf_lock) { return; } mp_disable_preemption(); #if MACH_KDB db_printf("cpu %d looping on simple_lock(%x)" "(=%x)", cpu_number(), l, *hw_lock_addr(l->interlock)); db_printf(" called by %x\n", pc); #endif Debugger("simple lock deadlock detection"); count = 0; mp_enable_preemption(); } #endif /* USLOCK_DEBUG */ } } ETAPCALL(etap_simplelock_hold(l, pc, start_wait_time)); USLDBG(usld_lock_post(l, pc)); }
void db_print_mutex ( mutex_t * addr) { db_printf ("%08x %6d %7d", addr, *hw_lock_addr(addr->locked), addr->waiters); #if MACH_LDEBUG db_printf (" %08x ", addr->thread); db_printsym (addr->pc, DB_STGY_ANY); #endif /* MACH_LDEBUG */ db_printf ("\n"); }
void db_print_simple_lock ( simple_lock_t addr) { db_printf ("%08x %3d", addr, *hw_lock_addr(addr->interlock)); #if USLOCK_DEBUG db_printf (" %08x", addr->debug.lock_thread); db_printf (" %08x ", addr->debug.duration[1]); db_printsym ((int)addr->debug.lock_pc, DB_STGY_ANY); #endif /* USLOCK_DEBUG */ db_printf ("\n"); }