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queue.c
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/*
* Copyright (c) 2008-2013 Apple Inc. All rights reserved.
*
* @APPLE_APACHE_LICENSE_HEADER_START@
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @APPLE_APACHE_LICENSE_HEADER_END@
*/
#include "internal.h"
#if HAVE_MACH
#include "protocol.h" // _dispatch_send_wakeup_runloop_thread
#endif
static inline void _dispatch_root_queues_init(void);
static void _dispatch_lane_barrier_complete(dispatch_lane_class_t dqu,
dispatch_qos_t qos, dispatch_wakeup_flags_t flags);
static void _dispatch_lane_non_barrier_complete(dispatch_lane_t dq,
dispatch_wakeup_flags_t flags);
#if HAVE_PTHREAD_WORKQUEUE_QOS
static inline void _dispatch_queue_wakeup_with_override(
dispatch_queue_class_t dq, uint64_t dq_state,
dispatch_wakeup_flags_t flags);
#endif
static void _dispatch_workloop_drain_barrier_waiter(dispatch_workloop_t dwl,
struct dispatch_object_s *dc, dispatch_qos_t qos,
dispatch_wakeup_flags_t flags, uint64_t owned);
#pragma mark -
#pragma mark dispatch_assert_queue
DISPATCH_NOINLINE DISPATCH_NORETURN
static void
_dispatch_assert_queue_fail(dispatch_queue_t dq, bool expected)
{
_dispatch_client_assert_fail(
"Block was %sexpected to execute on queue [%s]",
expected ? "" : "not ", dq->dq_label ?: "");
}
DISPATCH_NOINLINE DISPATCH_NORETURN
static void
_dispatch_assert_queue_barrier_fail(dispatch_queue_t dq)
{
_dispatch_client_assert_fail(
"Block was expected to act as a barrier on queue [%s]",
dq->dq_label ?: "");
}
void
dispatch_assert_queue(dispatch_queue_t dq)
{
unsigned long metatype = dx_metatype(dq);
if (unlikely(metatype != _DISPATCH_LANE_TYPE &&
metatype != _DISPATCH_WORKLOOP_TYPE)) {
DISPATCH_CLIENT_CRASH(metatype, "invalid queue passed to "
"dispatch_assert_queue()");
}
uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed);
if (likely(_dq_state_drain_locked_by_self(dq_state))) {
return;
}
if (likely(_dispatch_thread_frame_find_queue(dq))) {
return;
}
_dispatch_assert_queue_fail(dq, true);
}
void
dispatch_assert_queue_not(dispatch_queue_t dq)
{
unsigned long metatype = dx_metatype(dq);
if (unlikely(metatype != _DISPATCH_LANE_TYPE &&
metatype != _DISPATCH_WORKLOOP_TYPE)) {
DISPATCH_CLIENT_CRASH(metatype, "invalid queue passed to "
"dispatch_assert_queue_not()");
}
uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed);
if (unlikely(_dq_state_drain_locked_by_self(dq_state))) {
_dispatch_assert_queue_fail(dq, false);
}
if (unlikely(_dispatch_thread_frame_find_queue(dq))) {
_dispatch_assert_queue_fail(dq, false);
}
}
void
dispatch_assert_queue_barrier(dispatch_queue_t dq)
{
dispatch_assert_queue(dq);
if (likely(dq->dq_width == 1)) {
return;
}
if (likely(dq->do_targetq)) {
uint64_t dq_state = os_atomic_load2o(dq, dq_state, relaxed);
if (likely(_dq_state_is_in_barrier(dq_state))) {
return;
}
}
_dispatch_assert_queue_barrier_fail(dq);
}
#pragma mark -
#pragma mark _dispatch_set_priority_and_mach_voucher
#if HAVE_PTHREAD_WORKQUEUE_QOS
DISPATCH_NOINLINE
void
_dispatch_set_priority_and_mach_voucher_slow(pthread_priority_t pp,
mach_voucher_t kv)
{
_pthread_set_flags_t pflags = 0;
if (pp && _dispatch_set_qos_class_enabled) {
pthread_priority_t old_pri = _dispatch_get_priority();
if (pp != old_pri) {
if (old_pri & _PTHREAD_PRIORITY_NEEDS_UNBIND_FLAG) {
pflags |= _PTHREAD_SET_SELF_WQ_KEVENT_UNBIND;
// when we unbind, overcomitness can flip, so we need to learn
// it from the defaultpri, see _dispatch_priority_compute_update
pp |= (_dispatch_get_basepri() &
DISPATCH_PRIORITY_FLAG_OVERCOMMIT);
} else {
// else we need to keep the one that is set in the current pri
pp |= (old_pri & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG);
}
if (likely(old_pri & ~_PTHREAD_PRIORITY_FLAGS_MASK)) {
pflags |= _PTHREAD_SET_SELF_QOS_FLAG;
}
uint64_t mgr_dq_state =
os_atomic_load2o(&_dispatch_mgr_q, dq_state, relaxed);
if (unlikely(_dq_state_drain_locked_by_self(mgr_dq_state))) {
DISPATCH_INTERNAL_CRASH(pp,
"Changing the QoS while on the manager queue");
}
if (unlikely(pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG)) {
DISPATCH_INTERNAL_CRASH(pp, "Cannot raise oneself to manager");
}
if (old_pri & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) {
DISPATCH_INTERNAL_CRASH(old_pri,
"Cannot turn a manager thread into a normal one");
}
}
}
if (kv != VOUCHER_NO_MACH_VOUCHER) {
#if VOUCHER_USE_MACH_VOUCHER
pflags |= _PTHREAD_SET_SELF_VOUCHER_FLAG;
#endif
}
if (!pflags) return;
int r = _pthread_set_properties_self(pflags, pp, kv);
if (r == EINVAL) {
DISPATCH_INTERNAL_CRASH(pp, "_pthread_set_properties_self failed");
}
(void)dispatch_assume_zero(r);
}
DISPATCH_NOINLINE
voucher_t
_dispatch_set_priority_and_voucher_slow(pthread_priority_t priority,
voucher_t v, dispatch_thread_set_self_t flags)
{
voucher_t ov = DISPATCH_NO_VOUCHER;
mach_voucher_t kv = VOUCHER_NO_MACH_VOUCHER;
if (v != DISPATCH_NO_VOUCHER) {
bool retained = flags & DISPATCH_VOUCHER_CONSUME;
ov = _voucher_get();
if (ov == v && (flags & DISPATCH_VOUCHER_REPLACE)) {
if (retained && v) _voucher_release_no_dispose(v);
ov = DISPATCH_NO_VOUCHER;
} else {
if (!retained && v) _voucher_retain(v);
kv = _voucher_swap_and_get_mach_voucher(ov, v);
}
}
if (!(flags & DISPATCH_THREAD_PARK)) {
_dispatch_set_priority_and_mach_voucher_slow(priority, kv);
}
if (ov != DISPATCH_NO_VOUCHER && (flags & DISPATCH_VOUCHER_REPLACE)) {
if (ov) _voucher_release(ov);
ov = DISPATCH_NO_VOUCHER;
}
return ov;
}
#endif
#pragma mark -
#pragma mark dispatch_continuation_t
static void _dispatch_async_redirect_invoke(dispatch_continuation_t dc,
dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags);
#if HAVE_PTHREAD_WORKQUEUE_QOS
static void _dispatch_queue_override_invoke(dispatch_continuation_t dc,
dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags);
static void _dispatch_workloop_stealer_invoke(dispatch_continuation_t dc,
dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags);
#endif // HAVE_PTHREAD_WORKQUEUE_QOS
const struct dispatch_continuation_vtable_s _dispatch_continuation_vtables[] = {
DC_VTABLE_ENTRY(ASYNC_REDIRECT,
.do_invoke = _dispatch_async_redirect_invoke),
#if HAVE_MACH
DC_VTABLE_ENTRY(MACH_SEND_BARRRIER_DRAIN,
.do_invoke = _dispatch_mach_send_barrier_drain_invoke),
DC_VTABLE_ENTRY(MACH_SEND_BARRIER,
.do_invoke = _dispatch_mach_barrier_invoke),
DC_VTABLE_ENTRY(MACH_RECV_BARRIER,
.do_invoke = _dispatch_mach_barrier_invoke),
DC_VTABLE_ENTRY(MACH_ASYNC_REPLY,
.do_invoke = _dispatch_mach_msg_async_reply_invoke),
#endif
#if HAVE_PTHREAD_WORKQUEUE_QOS
DC_VTABLE_ENTRY(WORKLOOP_STEALING,
.do_invoke = _dispatch_workloop_stealer_invoke),
DC_VTABLE_ENTRY(OVERRIDE_STEALING,
.do_invoke = _dispatch_queue_override_invoke),
DC_VTABLE_ENTRY(OVERRIDE_OWNING,
.do_invoke = _dispatch_queue_override_invoke),
#endif
#if HAVE_MACH
DC_VTABLE_ENTRY(MACH_IPC_HANDOFF,
.do_invoke = _dispatch_mach_ipc_handoff_invoke),
#endif
};
DISPATCH_NOINLINE
static void DISPATCH_TSD_DTOR_CC
_dispatch_cache_cleanup(void *value)
{
dispatch_continuation_t dc, next_dc = value;
while ((dc = next_dc)) {
next_dc = dc->do_next;
_dispatch_continuation_free_to_heap(dc);
}
}
static void
_dispatch_force_cache_cleanup(void)
{
dispatch_continuation_t dc;
dc = _dispatch_thread_getspecific(dispatch_cache_key);
if (dc) {
_dispatch_thread_setspecific(dispatch_cache_key, NULL);
_dispatch_cache_cleanup(dc);
}
}
#if DISPATCH_USE_MEMORYPRESSURE_SOURCE
DISPATCH_NOINLINE
void
_dispatch_continuation_free_to_cache_limit(dispatch_continuation_t dc)
{
_dispatch_continuation_free_to_heap(dc);
dispatch_continuation_t next_dc;
dc = _dispatch_thread_getspecific(dispatch_cache_key);
int cnt;
if (!dc || (cnt = dc->dc_cache_cnt -
_dispatch_continuation_cache_limit) <= 0) {
return;
}
do {
next_dc = dc->do_next;
_dispatch_continuation_free_to_heap(dc);
} while (--cnt && (dc = next_dc));
_dispatch_thread_setspecific(dispatch_cache_key, next_dc);
}
#endif
DISPATCH_NOINLINE
void
_dispatch_continuation_pop(dispatch_object_t dou, dispatch_invoke_context_t dic,
dispatch_invoke_flags_t flags, dispatch_queue_class_t dqu)
{
_dispatch_continuation_pop_inline(dou, dic, flags, dqu._dq);
}
#pragma mark -
#pragma mark dispatch_block_create
#if __BLOCKS__
DISPATCH_ALWAYS_INLINE
static inline bool
_dispatch_block_flags_valid(dispatch_block_flags_t flags)
{
return ((flags & ~DISPATCH_BLOCK_API_MASK) == 0);
}
DISPATCH_ALWAYS_INLINE
static inline dispatch_block_flags_t
_dispatch_block_normalize_flags(dispatch_block_flags_t flags)
{
if (flags & (DISPATCH_BLOCK_NO_QOS_CLASS|DISPATCH_BLOCK_DETACHED)) {
flags |= DISPATCH_BLOCK_HAS_PRIORITY;
}
if (flags & DISPATCH_BLOCK_ENFORCE_QOS_CLASS) {
flags &= ~(dispatch_block_flags_t)DISPATCH_BLOCK_INHERIT_QOS_CLASS;
}
return flags;
}
static inline dispatch_block_t
_dispatch_block_create_with_voucher_and_priority(dispatch_block_flags_t flags,
voucher_t voucher, pthread_priority_t pri, dispatch_block_t block)
{
dispatch_block_flags_t unmodified_flags = flags;
pthread_priority_t unmodified_pri = pri;
flags = _dispatch_block_normalize_flags(flags);
bool assign = (flags & DISPATCH_BLOCK_ASSIGN_CURRENT);
if (!(flags & DISPATCH_BLOCK_HAS_VOUCHER)) {
if (flags & DISPATCH_BLOCK_DETACHED) {
voucher = VOUCHER_NULL;
flags |= DISPATCH_BLOCK_HAS_VOUCHER;
} else if (flags & DISPATCH_BLOCK_NO_VOUCHER) {
voucher = DISPATCH_NO_VOUCHER;
flags |= DISPATCH_BLOCK_HAS_VOUCHER;
} else if (assign) {
#if OS_VOUCHER_ACTIVITY_SPI
voucher = VOUCHER_CURRENT;
#endif
flags |= DISPATCH_BLOCK_HAS_VOUCHER;
}
}
#if OS_VOUCHER_ACTIVITY_SPI
if (voucher == VOUCHER_CURRENT) {
voucher = _voucher_get();
}
#endif
if (assign && !(flags & DISPATCH_BLOCK_HAS_PRIORITY)) {
pri = _dispatch_priority_propagate();
flags |= DISPATCH_BLOCK_HAS_PRIORITY;
}
dispatch_block_t db = _dispatch_block_create(flags, voucher, pri, block);
#if DISPATCH_DEBUG
dispatch_assert(_dispatch_block_get_data(db));
#endif
_dispatch_trace_block_create_with_voucher_and_priority(db,
_dispatch_Block_invoke(block), unmodified_flags,
((unmodified_flags & DISPATCH_BLOCK_HAS_PRIORITY) ? unmodified_pri :
(unsigned long)UINT32_MAX),
_dispatch_get_priority(), pri);
return db;
}
dispatch_block_t
dispatch_block_create(dispatch_block_flags_t flags, dispatch_block_t block)
{
if (!_dispatch_block_flags_valid(flags)) return DISPATCH_BAD_INPUT;
return _dispatch_block_create_with_voucher_and_priority(flags, NULL, 0,
block);
}
dispatch_block_t
dispatch_block_create_with_qos_class(dispatch_block_flags_t flags,
dispatch_qos_class_t qos_class, int relative_priority,
dispatch_block_t block)
{
if (!_dispatch_block_flags_valid(flags) ||
!_dispatch_qos_class_valid(qos_class, relative_priority)) {
return DISPATCH_BAD_INPUT;
}
flags |= DISPATCH_BLOCK_HAS_PRIORITY;
pthread_priority_t pri = 0;
#if HAVE_PTHREAD_WORKQUEUE_QOS
pri = _pthread_qos_class_encode(qos_class, relative_priority, 0);
#endif
return _dispatch_block_create_with_voucher_and_priority(flags, NULL,
pri, block);
}
dispatch_block_t
dispatch_block_create_with_voucher(dispatch_block_flags_t flags,
voucher_t voucher, dispatch_block_t block)
{
if (!_dispatch_block_flags_valid(flags)) return DISPATCH_BAD_INPUT;
flags |= DISPATCH_BLOCK_HAS_VOUCHER;
flags &= ~DISPATCH_BLOCK_NO_VOUCHER;
return _dispatch_block_create_with_voucher_and_priority(flags, voucher, 0,
block);
}
dispatch_block_t
dispatch_block_create_with_voucher_and_qos_class(dispatch_block_flags_t flags,
voucher_t voucher, dispatch_qos_class_t qos_class,
int relative_priority, dispatch_block_t block)
{
if (!_dispatch_block_flags_valid(flags) ||
!_dispatch_qos_class_valid(qos_class, relative_priority)) {
return DISPATCH_BAD_INPUT;
}
flags |= (DISPATCH_BLOCK_HAS_VOUCHER|DISPATCH_BLOCK_HAS_PRIORITY);
flags &= ~(DISPATCH_BLOCK_NO_VOUCHER|DISPATCH_BLOCK_NO_QOS_CLASS);
pthread_priority_t pri = 0;
#if HAVE_PTHREAD_WORKQUEUE_QOS
pri = _pthread_qos_class_encode(qos_class, relative_priority, 0);
#endif
return _dispatch_block_create_with_voucher_and_priority(flags, voucher,
pri, block);
}
void
dispatch_block_perform(dispatch_block_flags_t flags, dispatch_block_t block)
{
if (!_dispatch_block_flags_valid(flags)) {
DISPATCH_CLIENT_CRASH(flags, "Invalid flags passed to "
"dispatch_block_perform()");
}
flags = _dispatch_block_normalize_flags(flags);
voucher_t voucher = DISPATCH_NO_VOUCHER;
if (flags & DISPATCH_BLOCK_DETACHED) {
voucher = VOUCHER_NULL;
flags |= DISPATCH_BLOCK_HAS_VOUCHER;
}
struct dispatch_block_private_data_s dbpds =
DISPATCH_BLOCK_PRIVATE_DATA_PERFORM_INITIALIZER(flags, block, voucher);
return _dispatch_block_invoke_direct(&dbpds);
}
void
_dispatch_block_invoke_direct(const struct dispatch_block_private_data_s *dbcpd)
{
dispatch_block_private_data_t dbpd = (dispatch_block_private_data_t)dbcpd;
dispatch_block_flags_t flags = dbpd->dbpd_flags;
unsigned int atomic_flags = dbpd->dbpd_atomic_flags;
if (unlikely(atomic_flags & DBF_WAITED)) {
DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both "
"run more than once and waited for");
}
if (atomic_flags & DBF_CANCELED) goto out;
pthread_priority_t op = 0, p = 0;
op = _dispatch_block_invoke_should_set_priority(flags, dbpd->dbpd_priority);
if (op) {
p = dbpd->dbpd_priority;
}
voucher_t ov, v = DISPATCH_NO_VOUCHER;
if (flags & DISPATCH_BLOCK_HAS_VOUCHER) {
v = dbpd->dbpd_voucher;
}
ov = _dispatch_set_priority_and_voucher(p, v, 0);
dbpd->dbpd_thread = _dispatch_tid_self();
_dispatch_client_callout(dbpd->dbpd_block,
_dispatch_Block_invoke(dbpd->dbpd_block));
_dispatch_reset_priority_and_voucher(op, ov);
out:
if ((atomic_flags & DBF_PERFORM) == 0) {
if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) {
dispatch_group_leave(dbpd->dbpd_group);
}
}
}
void
_dispatch_block_sync_invoke(void *block)
{
dispatch_block_t b = block;
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(b);
dispatch_block_flags_t flags = dbpd->dbpd_flags;
unsigned int atomic_flags = dbpd->dbpd_atomic_flags;
if (unlikely(atomic_flags & DBF_WAITED)) {
DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both "
"run more than once and waited for");
}
if (atomic_flags & DBF_CANCELED) goto out;
voucher_t ov = DISPATCH_NO_VOUCHER;
if (flags & DISPATCH_BLOCK_HAS_VOUCHER) {
ov = _dispatch_adopt_priority_and_set_voucher(0, dbpd->dbpd_voucher, 0);
}
dbpd->dbpd_block();
_dispatch_reset_voucher(ov, 0);
out:
if ((atomic_flags & DBF_PERFORM) == 0) {
if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) {
dispatch_group_leave(dbpd->dbpd_group);
}
}
dispatch_queue_t boost_dq;
boost_dq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed);
if (boost_dq) {
// balances dispatch_{,barrier_,}sync
_dispatch_release_2(boost_dq);
}
}
#define DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE 0x1
DISPATCH_NOINLINE
static void
_dispatch_block_async_invoke2(dispatch_block_t b, unsigned long invoke_flags)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(b);
unsigned int atomic_flags = dbpd->dbpd_atomic_flags;
if (unlikely(atomic_flags & DBF_WAITED)) {
DISPATCH_CLIENT_CRASH(atomic_flags, "A block object may not be both "
"run more than once and waited for");
}
if (likely(!(atomic_flags & DBF_CANCELED))) {
dbpd->dbpd_block();
}
if ((atomic_flags & DBF_PERFORM) == 0) {
if (os_atomic_inc2o(dbpd, dbpd_performed, relaxed) == 1) {
dispatch_group_leave(dbpd->dbpd_group);
}
}
dispatch_queue_t boost_dq;
boost_dq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed);
if (boost_dq) {
// balances dispatch_{,barrier_,group_}async
_dispatch_release_2(boost_dq);
}
if (invoke_flags & DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE) {
Block_release(b);
}
}
static void
_dispatch_block_async_invoke(void *block)
{
_dispatch_block_async_invoke2(block, 0);
}
static void
_dispatch_block_async_invoke_and_release(void *block)
{
_dispatch_block_async_invoke2(block, DISPATCH_BLOCK_ASYNC_INVOKE_RELEASE);
}
void
dispatch_block_cancel(dispatch_block_t db)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db);
if (unlikely(!dbpd)) {
DISPATCH_CLIENT_CRASH(0, "Invalid block object passed to "
"dispatch_block_cancel()");
}
(void)os_atomic_or2o(dbpd, dbpd_atomic_flags, DBF_CANCELED, relaxed);
}
intptr_t
dispatch_block_testcancel(dispatch_block_t db)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db);
if (unlikely(!dbpd)) {
DISPATCH_CLIENT_CRASH(0, "Invalid block object passed to "
"dispatch_block_testcancel()");
}
return (bool)(dbpd->dbpd_atomic_flags & DBF_CANCELED);
}
intptr_t
dispatch_block_wait(dispatch_block_t db, dispatch_time_t timeout)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db);
if (unlikely(!dbpd)) {
DISPATCH_CLIENT_CRASH(0, "Invalid block object passed to "
"dispatch_block_wait()");
}
unsigned int flags = os_atomic_or_orig2o(dbpd, dbpd_atomic_flags,
DBF_WAITING, relaxed);
if (unlikely(flags & (DBF_WAITED | DBF_WAITING))) {
DISPATCH_CLIENT_CRASH(flags, "A block object may not be waited for "
"more than once");
}
// <rdar://problem/17703192> If we know the queue where this block is
// enqueued, or the thread that's executing it, then we should boost
// it here.
pthread_priority_t pp = _dispatch_get_priority();
dispatch_queue_t boost_dq;
boost_dq = os_atomic_xchg2o(dbpd, dbpd_queue, NULL, relaxed);
if (boost_dq) {
// release balances dispatch_{,barrier_,group_}async.
// Can't put the queue back in the timeout case: the block might
// finish after we fell out of group_wait and see our NULL, so
// neither of us would ever release. Side effect: After a _wait
// that times out, subsequent waits will not boost the qos of the
// still-running block.
dx_wakeup(boost_dq, _dispatch_qos_from_pp(pp),
DISPATCH_WAKEUP_BLOCK_WAIT | DISPATCH_WAKEUP_CONSUME_2);
}
mach_port_t boost_th = dbpd->dbpd_thread;
if (boost_th) {
_dispatch_thread_override_start(boost_th, pp, dbpd);
}
int performed = os_atomic_load2o(dbpd, dbpd_performed, relaxed);
if (unlikely(performed > 1 || (boost_th && boost_dq))) {
DISPATCH_CLIENT_CRASH(performed, "A block object may not be both "
"run more than once and waited for");
}
long ret = dispatch_group_wait(dbpd->dbpd_group, timeout);
if (boost_th) {
_dispatch_thread_override_end(boost_th, dbpd);
}
if (ret) {
// timed out: reverse our changes
os_atomic_and2o(dbpd, dbpd_atomic_flags, ~DBF_WAITING, relaxed);
} else {
os_atomic_or2o(dbpd, dbpd_atomic_flags, DBF_WAITED, relaxed);
// don't need to re-test here: the second call would see
// the first call's WAITING
}
return ret;
}
void
dispatch_block_notify(dispatch_block_t db, dispatch_queue_t queue,
dispatch_block_t notification_block)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(db);
if (!dbpd) {
DISPATCH_CLIENT_CRASH(db, "Invalid block object passed to "
"dispatch_block_notify()");
}
int performed = os_atomic_load2o(dbpd, dbpd_performed, relaxed);
if (unlikely(performed > 1)) {
DISPATCH_CLIENT_CRASH(performed, "A block object may not be both "
"run more than once and observed");
}
return dispatch_group_notify(dbpd->dbpd_group, queue, notification_block);
}
DISPATCH_NOINLINE
dispatch_qos_t
_dispatch_continuation_init_slow(dispatch_continuation_t dc,
dispatch_queue_t dq, dispatch_block_flags_t flags)
{
dispatch_block_private_data_t dbpd = _dispatch_block_get_data(dc->dc_ctxt);
dispatch_block_flags_t block_flags = dbpd->dbpd_flags;
uintptr_t dc_flags = dc->dc_flags;
pthread_priority_t pp = 0;
// balanced in d_block_async_invoke_and_release or d_block_wait
if (os_atomic_cmpxchg2o(dbpd, dbpd_queue, NULL, dq, relaxed)) {
_dispatch_retain_2(dq);
}
if (dc_flags & DC_FLAG_CONSUME) {
dc->dc_func = _dispatch_block_async_invoke_and_release;
} else {
dc->dc_func = _dispatch_block_async_invoke;
}
flags |= block_flags;
if (block_flags & DISPATCH_BLOCK_HAS_PRIORITY) {
pp = dbpd->dbpd_priority & ~_PTHREAD_PRIORITY_FLAGS_MASK;
} else if (flags & DISPATCH_BLOCK_HAS_PRIORITY) {
// _dispatch_source_handler_alloc is calling is and doesn't want us
// to propagate priorities
pp = 0;
} else {
pp = _dispatch_priority_propagate();
}
_dispatch_continuation_priority_set(dc, dq, pp, flags);
if (block_flags & DISPATCH_BLOCK_BARRIER) {
dc_flags |= DC_FLAG_BARRIER;
}
if (block_flags & DISPATCH_BLOCK_HAS_VOUCHER) {
voucher_t v = dbpd->dbpd_voucher;
dc->dc_voucher = (v && v != DISPATCH_NO_VOUCHER) ? _voucher_retain(v)
: v;
_dispatch_voucher_debug("continuation[%p] set", dc->dc_voucher, dc);
_dispatch_voucher_ktrace_dc_push(dc);
} else {
_dispatch_continuation_voucher_set(dc, flags);
}
dc_flags |= DC_FLAG_BLOCK_WITH_PRIVATE_DATA;
dc->dc_flags = dc_flags;
return _dispatch_qos_from_pp(dc->dc_priority);
}
#endif // __BLOCKS__
#pragma mark -
#pragma mark dispatch_barrier_async
DISPATCH_NOINLINE
static void
_dispatch_async_f_slow(dispatch_queue_t dq, void *ctxt,
dispatch_function_t func, dispatch_block_flags_t flags,
uintptr_t dc_flags)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc_from_heap();
dispatch_qos_t qos;
qos = _dispatch_continuation_init_f(dc, dq, ctxt, func, flags, dc_flags);
_dispatch_continuation_async(dq, dc, qos, dc->dc_flags);
}
DISPATCH_NOINLINE
void
dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt,
dispatch_function_t func)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc_cacheonly();
uintptr_t dc_flags = DC_FLAG_CONSUME | DC_FLAG_BARRIER;
dispatch_qos_t qos;
if (likely(!dc)) {
return _dispatch_async_f_slow(dq, ctxt, func, 0, dc_flags);
}
qos = _dispatch_continuation_init_f(dc, dq, ctxt, func, 0, dc_flags);
_dispatch_continuation_async(dq, dc, qos, dc_flags);
}
DISPATCH_NOINLINE
void
_dispatch_barrier_async_detached_f(dispatch_queue_class_t dq, void *ctxt,
dispatch_function_t func)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc();
dc->dc_flags = DC_FLAG_CONSUME | DC_FLAG_BARRIER | DC_FLAG_ALLOCATED;
dc->dc_func = func;
dc->dc_ctxt = ctxt;
dc->dc_voucher = DISPATCH_NO_VOUCHER;
dc->dc_priority = DISPATCH_NO_PRIORITY;
_dispatch_trace_item_push(dq, dc);
dx_push(dq._dq, dc, 0);
}
#ifdef __BLOCKS__
void
dispatch_barrier_async(dispatch_queue_t dq, dispatch_block_t work)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc();
uintptr_t dc_flags = DC_FLAG_CONSUME | DC_FLAG_BARRIER;
dispatch_qos_t qos;
qos = _dispatch_continuation_init(dc, dq, work, 0, dc_flags);
_dispatch_continuation_async(dq, dc, qos, dc_flags);
}
#endif
#pragma mark -
#pragma mark dispatch_async
void
_dispatch_async_redirect_invoke(dispatch_continuation_t dc,
dispatch_invoke_context_t dic, dispatch_invoke_flags_t flags)
{
dispatch_thread_frame_s dtf;
struct dispatch_continuation_s *other_dc = dc->dc_other;
dispatch_invoke_flags_t ctxt_flags = (dispatch_invoke_flags_t)(uintptr_t)dc->dc_ctxt;
// if we went through _dispatch_root_queue_push_override,
// the "right" root queue was stuffed into dc_func
dispatch_queue_global_t assumed_rq = (dispatch_queue_global_t)dc->dc_func;
dispatch_lane_t dq = dc->dc_data;
dispatch_queue_t rq, old_dq;
dispatch_priority_t old_dbp;
if (ctxt_flags) {
flags &= ~_DISPATCH_INVOKE_AUTORELEASE_MASK;
flags |= ctxt_flags;
}
old_dq = _dispatch_queue_get_current();
if (assumed_rq) {
old_dbp = _dispatch_root_queue_identity_assume(assumed_rq);
_dispatch_set_basepri(dq->dq_priority);
} else {
old_dbp = _dispatch_set_basepri(dq->dq_priority);
}
uintptr_t dc_flags = DC_FLAG_CONSUME | DC_FLAG_NO_INTROSPECTION;
_dispatch_thread_frame_push(&dtf, dq);
_dispatch_continuation_pop_forwarded(dc, dc_flags, NULL, {
_dispatch_continuation_pop(other_dc, dic, flags, dq);
});
_dispatch_thread_frame_pop(&dtf);
if (assumed_rq) _dispatch_queue_set_current(old_dq);
_dispatch_reset_basepri(old_dbp);
rq = dq->do_targetq;
while (unlikely(rq->do_targetq && rq != old_dq)) {
_dispatch_lane_non_barrier_complete(upcast(rq)._dl, 0);
rq = rq->do_targetq;
}
// pairs with _dispatch_async_redirect_wrap
_dispatch_lane_non_barrier_complete(dq, DISPATCH_WAKEUP_CONSUME_2);
}
DISPATCH_ALWAYS_INLINE
static inline dispatch_continuation_t
_dispatch_async_redirect_wrap(dispatch_lane_t dq, dispatch_object_t dou)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc();
dou._do->do_next = NULL;
dc->do_vtable = DC_VTABLE(ASYNC_REDIRECT);
dc->dc_func = NULL;
dc->dc_ctxt = (void *)(uintptr_t)_dispatch_queue_autorelease_frequency(dq);
dc->dc_data = dq;
dc->dc_other = dou._do;
dc->dc_voucher = DISPATCH_NO_VOUCHER;
dc->dc_priority = DISPATCH_NO_PRIORITY;
_dispatch_retain_2(dq); // released in _dispatch_async_redirect_invoke
return dc;
}
DISPATCH_NOINLINE
static void
_dispatch_continuation_redirect_push(dispatch_lane_t dl,
dispatch_object_t dou, dispatch_qos_t qos)
{
if (likely(!_dispatch_object_is_redirection(dou))) {
dou._dc = _dispatch_async_redirect_wrap(dl, dou);
} else if (!dou._dc->dc_ctxt) {
// find first queue in descending target queue order that has
// an autorelease frequency set, and use that as the frequency for
// this continuation.
dou._dc->dc_ctxt = (void *)
(uintptr_t)_dispatch_queue_autorelease_frequency(dl);
}
dispatch_queue_t dq = dl->do_targetq;
if (!qos) qos = _dispatch_priority_qos(dq->dq_priority);
dx_push(dq, dou, qos);
}
DISPATCH_ALWAYS_INLINE
static inline void
_dispatch_async_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t func,
dispatch_block_flags_t flags)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc_cacheonly();
uintptr_t dc_flags = DC_FLAG_CONSUME;
dispatch_qos_t qos;
if (unlikely(!dc)) {
return _dispatch_async_f_slow(dq, ctxt, func, flags, dc_flags);
}
qos = _dispatch_continuation_init_f(dc, dq, ctxt, func, flags, dc_flags);
_dispatch_continuation_async(dq, dc, qos, dc->dc_flags);
}
DISPATCH_NOINLINE
void
dispatch_async_f(dispatch_queue_t dq, void *ctxt, dispatch_function_t func)
{
_dispatch_async_f(dq, ctxt, func, 0);
}
DISPATCH_NOINLINE
void
dispatch_async_enforce_qos_class_f(dispatch_queue_t dq, void *ctxt,
dispatch_function_t func)
{
_dispatch_async_f(dq, ctxt, func, DISPATCH_BLOCK_ENFORCE_QOS_CLASS);
}
#ifdef __BLOCKS__
void
dispatch_async(dispatch_queue_t dq, dispatch_block_t work)
{
dispatch_continuation_t dc = _dispatch_continuation_alloc();
uintptr_t dc_flags = DC_FLAG_CONSUME;
dispatch_qos_t qos;
qos = _dispatch_continuation_init(dc, dq, work, 0, dc_flags);
_dispatch_continuation_async(dq, dc, qos, dc->dc_flags);
}
#endif
#pragma mark -
#pragma mark _dispatch_sync_invoke / _dispatch_sync_complete
DISPATCH_ALWAYS_INLINE
static uint64_t
_dispatch_lane_non_barrier_complete_try_lock(dispatch_lane_t dq,
uint64_t old_state, uint64_t new_state, uint64_t owner_self)
{
uint64_t full_width = new_state;
if (_dq_state_has_pending_barrier(new_state)) {
full_width -= DISPATCH_QUEUE_PENDING_BARRIER;
full_width += DISPATCH_QUEUE_WIDTH_INTERVAL;
full_width += DISPATCH_QUEUE_IN_BARRIER;
} else {
full_width += dq->dq_width * DISPATCH_QUEUE_WIDTH_INTERVAL;
full_width += DISPATCH_QUEUE_IN_BARRIER;
}
if ((full_width & DISPATCH_QUEUE_WIDTH_MASK) ==
DISPATCH_QUEUE_WIDTH_FULL_BIT) {
new_state = full_width;
new_state &= ~DISPATCH_QUEUE_DIRTY;
new_state |= owner_self;
} else if (_dq_state_is_dirty(old_state)) {
new_state |= DISPATCH_QUEUE_ENQUEUED;
}
return new_state;
}
DISPATCH_ALWAYS_INLINE
static void
_dispatch_lane_non_barrier_complete_finish(dispatch_lane_t dq,
dispatch_wakeup_flags_t flags, uint64_t old_state, uint64_t new_state)
{
if (_dq_state_received_override(old_state)) {
// Ensure that the root queue sees that this thread was overridden.
_dispatch_set_basepri_override_qos(_dq_state_max_qos(old_state));
}
if ((old_state ^ new_state) & DISPATCH_QUEUE_IN_BARRIER) {
if (_dq_state_is_dirty(old_state)) {
// <rdar://problem/14637483>
// dependency ordering for dq state changes that were flushed
// and not acted upon
os_atomic_thread_fence(dependency);
dq = os_atomic_force_dependency_on(dq, old_state);
}
return _dispatch_lane_barrier_complete(dq, 0, flags);
}
if ((old_state ^ new_state) & DISPATCH_QUEUE_ENQUEUED) {
if (!(flags & DISPATCH_WAKEUP_CONSUME_2)) {
_dispatch_retain_2(dq);
}
dispatch_assert(!_dq_state_is_base_wlh(new_state));
_dispatch_trace_item_push(dq->do_targetq, dq);
return dx_push(dq->do_targetq, dq, _dq_state_max_qos(new_state));
}
if (flags & DISPATCH_WAKEUP_CONSUME_2) {
_dispatch_release_2_tailcall(dq);
}
}
DISPATCH_NOINLINE
static void
_dispatch_lane_non_barrier_complete(dispatch_lane_t dq,
dispatch_wakeup_flags_t flags)
{
uint64_t old_state, new_state, owner_self = _dispatch_lock_value_for_self();
// see _dispatch_lane_resume()
os_atomic_rmw_loop2o(dq, dq_state, old_state, new_state, relaxed, {
new_state = old_state - DISPATCH_QUEUE_WIDTH_INTERVAL;
if (unlikely(_dq_state_drain_locked(old_state))) {
// make drain_try_unlock() fail and reconsider whether there's
// enough width now for a new item
new_state |= DISPATCH_QUEUE_DIRTY;
} else if (likely(_dq_state_is_runnable(new_state))) {
new_state = _dispatch_lane_non_barrier_complete_try_lock(dq,
old_state, new_state, owner_self);
}
});
_dispatch_lane_non_barrier_complete_finish(dq, flags, old_state, new_state);
}
DISPATCH_ALWAYS_INLINE
static inline void
_dispatch_sync_function_invoke_inline(dispatch_queue_class_t dq, void *ctxt,
dispatch_function_t func)
{
dispatch_thread_frame_s dtf;
_dispatch_thread_frame_push(&dtf, dq);
_dispatch_client_callout(ctxt, func);
_dispatch_perfmon_workitem_inc();
_dispatch_thread_frame_pop(&dtf);
}
DISPATCH_NOINLINE
static void
_dispatch_sync_function_invoke(dispatch_queue_class_t dq, void *ctxt,
dispatch_function_t func)
{