static int tegra_cpufreq_freq_helper(SYSCTLFN_ARGS) { struct sysctlnode node; int fq, oldfq = 0, error; uint64_t xc; node = *rnode; node.sysctl_data = &fq; fq = cpufreq_get_rate(); if (rnode->sysctl_num == cpufreq_node_target) oldfq = fq; error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) return error; if (fq == oldfq || rnode->sysctl_num != cpufreq_node_target) return 0; if (atomic_cas_uint(&cpufreq_busy, 0, 1) != 0) return EBUSY; error = cpufreq_set_rate(fq); if (error == 0) { xc = xc_broadcast(0, tegra_cpufreq_post, NULL, NULL); xc_wait(xc); pmf_event_inject(NULL, PMFE_SPEED_CHANGED); } atomic_dec_uint(&cpufreq_busy); return error; }
static VALUE ir_compare_and_set(volatile VALUE self, VALUE expect_value, VALUE new_value) { #if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050 if (OSAtomicCompareAndSwap64(expect_value, new_value, &DATA_PTR(self))) { return Qtrue; } #elif defined(__sun) /* Assuming VALUE is uintptr_t */ /* Based on the definition of uintptr_t from /usr/include/sys/int_types.h */ #if defined(_LP64) || defined(_I32LPx) /* 64-bit: uintptr_t === unsigned long */ if (atomic_cas_ulong((uintptr_t *) &DATA_PTR(self), expect_value, new_value)) { return Qtrue; } #else /* 32-bit: uintptr_t === unsigned int */ if (atomic_cas_uint((uintptr_t *) &DATA_PTR(self), expect_value, new_value)) { return Qtrue; } #endif #elif defined _MSC_VER && defined _M_AMD64 if (InterlockedCompareExchange64((LONGLONG*)&DATA_PTR(self), new_value, expect_value)) { return Qtrue; } #elif defined _MSC_VER && defined _M_IX86 if (InterlockedCompareExchange((LONG*)&DATA_PTR(self), new_value, expect_value)) { return Qtrue; } #else if (__sync_bool_compare_and_swap(&DATA_PTR(self), expect_value, new_value)) { return Qtrue; } #endif return Qfalse; }
bool refcount_inc(struct refcount *r) { unsigned int nval; unsigned int oval = atomic_load_uint(&r->val); while (true) { nval = oval + 1; /* r->val is 0, we can't do anything more. */ if (!oval) return false; if (atomic_cas_uint(&r->val, &oval, nval)) return true; /* * At this point atomic_cas_uint() has updated oval to the * current r->val. */ } }
bool refcount_dec(struct refcount *r) { unsigned int nval; unsigned int oval = atomic_load_uint(&r->val); while (true) { assert(oval); nval = oval - 1; if (atomic_cas_uint(&r->val, &oval, nval)) { /* * Value has been updated, if value was set to 0 * return true to indicate that. */ return !nval; } /* * At this point atomic_cas_uint() has updated oval to the * current r->val. */ } }
mblk_t * oce_ring_tx(void *ring_handle, mblk_t *mp) { struct oce_wq *wq = ring_handle; mblk_t *nxt_pkt; mblk_t *rmp = NULL; struct oce_dev *dev = wq->parent; if (dev->suspended) { freemsg(mp); return (NULL); } while (mp != NULL) { /* Save the Pointer since mp will be freed in case of copy */ nxt_pkt = mp->b_next; mp->b_next = NULL; /* Hardcode wq since we have only one */ rmp = oce_send_packet(wq, mp); if (rmp != NULL) { /* restore the chain */ rmp->b_next = nxt_pkt; break; } mp = nxt_pkt; } if (wq->resched) { if (atomic_cas_uint(&wq->qmode, OCE_MODE_POLL, OCE_MODE_INTR) == OCE_MODE_POLL) { oce_arm_cq(wq->parent, wq->cq->cq_id, 0, B_TRUE); wq->last_armed = ddi_get_lbolt(); } } return (rmp); }
static bool atomic_cas(sp_counted_base_atomic_type volatile *pw,int old_value,int new_value) { return atomic_cas_uint(&pw->ui,unsigned(old_value),unsigned(new_value))==unsigned(old_value); }
int turnstile_block(turnstile_t *ts, int qnum, void *sobj, sobj_ops_t *sobj_ops, kmutex_t *mp, lwp_timer_t *lwptp) { kthread_t *owner; kthread_t *t = curthread; proc_t *p = ttoproc(t); klwp_t *lwp = ttolwp(t); turnstile_chain_t *tc = &TURNSTILE_CHAIN(sobj); int error = 0; int loser = 0; ASSERT(DISP_LOCK_HELD(&tc->tc_lock)); ASSERT(mp == NULL || IS_UPI(mp)); ASSERT((SOBJ_TYPE(sobj_ops) == SOBJ_USER_PI) ^ (mp == NULL)); thread_lock_high(t); if (ts == NULL) { /* * This is the first thread to block on this sobj. * Take its attached turnstile and add it to the hash chain. */ ts = t->t_ts; ts->ts_sobj = sobj; ts->ts_next = tc->tc_first; tc->tc_first = ts; ASSERT(ts->ts_waiters == 0); } else { /* * Another thread has already donated its turnstile * to block on this sobj, so ours isn't needed. * Stash it on the active turnstile's freelist. */ turnstile_t *myts = t->t_ts; myts->ts_free = ts->ts_free; ts->ts_free = myts; t->t_ts = ts; ASSERT(ts->ts_sobj == sobj); ASSERT(ts->ts_waiters > 0); } /* * Put the thread to sleep. */ ASSERT(t != CPU->cpu_idle_thread); ASSERT(CPU_ON_INTR(CPU) == 0); ASSERT(t->t_wchan0 == NULL && t->t_wchan == NULL); ASSERT(t->t_state == TS_ONPROC); if (SOBJ_TYPE(sobj_ops) == SOBJ_USER_PI) { curthread->t_flag |= T_WAKEABLE; } CL_SLEEP(t); /* assign kernel priority */ THREAD_SLEEP(t, &tc->tc_lock); t->t_wchan = sobj; t->t_sobj_ops = sobj_ops; DTRACE_SCHED(sleep); if (lwp != NULL) { lwp->lwp_ru.nvcsw++; (void) new_mstate(t, LMS_SLEEP); if (SOBJ_TYPE(sobj_ops) == SOBJ_USER_PI) { lwp->lwp_asleep = 1; lwp->lwp_sysabort = 0; /* * make wchan0 non-zero to conform to the rule that * threads blocking for user-level objects have a * non-zero wchan0: this prevents spurious wake-ups * by, for example, /proc. */ t->t_wchan0 = (caddr_t)1; } } ts->ts_waiters++; sleepq_insert(&ts->ts_sleepq[qnum], t); if (SOBJ_TYPE(sobj_ops) == SOBJ_MUTEX && SOBJ_OWNER(sobj_ops, sobj) == NULL) panic("turnstile_block(%p): unowned mutex", (void *)ts); /* * Follow the blocking chain to its end, willing our priority to * everyone who's in our way. */ while (t->t_sobj_ops != NULL && (owner = SOBJ_OWNER(t->t_sobj_ops, t->t_wchan)) != NULL) { if (owner == curthread) { if (SOBJ_TYPE(sobj_ops) != SOBJ_USER_PI) { panic("Deadlock: cycle in blocking chain"); } /* * If the cycle we've encountered ends in mp, * then we know it isn't a 'real' cycle because * we're going to drop mp before we go to sleep. * Moreover, since we've come full circle we know * that we must have willed priority to everyone * in our way. Therefore, we can break out now. */ if (t->t_wchan == (void *)mp) break; if (loser) lock_clear(&turnstile_loser_lock); /* * For SOBJ_USER_PI, a cycle is an application * deadlock which needs to be communicated * back to the application. */ thread_unlock_nopreempt(t); mutex_exit(mp); setrun(curthread); swtch(); /* necessary to transition state */ curthread->t_flag &= ~T_WAKEABLE; if (lwptp->lwpt_id != 0) (void) lwp_timer_dequeue(lwptp); setallwatch(); lwp->lwp_asleep = 0; lwp->lwp_sysabort = 0; return (EDEADLK); } if (!turnstile_interlock(t->t_lockp, &owner->t_lockp)) { /* * If we failed to grab the owner's thread lock, * turnstile_interlock() will have dropped t's * thread lock, so at this point we don't even know * that 't' exists anymore. The simplest solution * is to restart the entire priority inheritance dance * from the beginning of the blocking chain, since * we *do* know that 'curthread' still exists. * Application of priority inheritance is idempotent, * so it's OK that we're doing it more than once. * Note also that since we've dropped our thread lock, * we may already have been woken up; if so, our * t_sobj_ops will be NULL, the loop will terminate, * and the call to swtch() will be a no-op. Phew. * * There is one further complication: if two (or more) * threads keep trying to grab the turnstile locks out * of order and keep losing the race to another thread, * these "dueling losers" can livelock the system. * Therefore, once we get into this rare situation, * we serialize all the losers. */ if (loser == 0) { loser = 1; lock_set(&turnstile_loser_lock); } t = curthread; thread_lock_high(t); continue; } /* * We now have the owner's thread lock. If we are traversing * from non-SOBJ_USER_PI ops to SOBJ_USER_PI ops, then we know * that we have caught the thread while in the TS_SLEEP state, * but holding mp. We know that this situation is transient * (mp will be dropped before the holder actually sleeps on * the SOBJ_USER_PI sobj), so we will spin waiting for mp to * be dropped. Then, as in the turnstile_interlock() failure * case, we will restart the priority inheritance dance. */ if (SOBJ_TYPE(t->t_sobj_ops) != SOBJ_USER_PI && owner->t_sobj_ops != NULL && SOBJ_TYPE(owner->t_sobj_ops) == SOBJ_USER_PI) { kmutex_t *upi_lock = (kmutex_t *)t->t_wchan; ASSERT(IS_UPI(upi_lock)); ASSERT(SOBJ_TYPE(t->t_sobj_ops) == SOBJ_MUTEX); if (t->t_lockp != owner->t_lockp) thread_unlock_high(owner); thread_unlock_high(t); if (loser) lock_clear(&turnstile_loser_lock); while (mutex_owner(upi_lock) == owner) { SMT_PAUSE(); continue; } if (loser) lock_set(&turnstile_loser_lock); t = curthread; thread_lock_high(t); continue; } turnstile_pi_inherit(t->t_ts, owner, DISP_PRIO(t)); if (t->t_lockp != owner->t_lockp) thread_unlock_high(t); t = owner; } if (loser) lock_clear(&turnstile_loser_lock); /* * Note: 't' and 'curthread' were synonymous before the loop above, * but now they may be different. ('t' is now the last thread in * the blocking chain.) */ if (SOBJ_TYPE(sobj_ops) == SOBJ_USER_PI) { ushort_t s = curthread->t_oldspl; int timedwait = 0; uint_t imm_timeout = 0; clock_t tim = -1; thread_unlock_high(t); if (lwptp->lwpt_id != 0) { /* * We enqueued a timeout. If it has already fired, * lwptp->lwpt_imm_timeout has been set with cas, * so fetch it with cas. */ timedwait = 1; imm_timeout = atomic_cas_uint(&lwptp->lwpt_imm_timeout, 0, 0); } mutex_exit(mp); splx(s); if (ISSIG(curthread, JUSTLOOKING) || MUSTRETURN(p, curthread) || imm_timeout) setrun(curthread); swtch(); curthread->t_flag &= ~T_WAKEABLE; if (timedwait) tim = lwp_timer_dequeue(lwptp); setallwatch(); if (ISSIG(curthread, FORREAL) || lwp->lwp_sysabort || MUSTRETURN(p, curthread)) error = EINTR; else if (imm_timeout || (timedwait && tim == -1)) error = ETIME; lwp->lwp_sysabort = 0; lwp->lwp_asleep = 0; } else { thread_unlock_nopreempt(t); swtch(); } return (error); }