/* Print DBG() messages about events lost only every 1048576 hits */
#define DBG_PRINT_NR_LOST (1UL << 20)
-#define LTTNG_UST_RB_SIG SIGRTMIN
-#define LTTNG_UST_RB_SIG_TEARDOWN SIGRTMIN + 1
+#define LTTNG_UST_RB_SIG_FLUSH SIGRTMIN
+#define LTTNG_UST_RB_SIG_READ SIGRTMIN + 1
+#define LTTNG_UST_RB_SIG_TEARDOWN SIGRTMIN + 2
#define CLOCKID CLOCK_MONOTONIC
/*
* Handle timer teardown race wrt memory free of private data by
* ring buffer signals are handled by a single thread, which permits
* a synchronization point between handling of each signal.
- * Protected by the ust mutex.
+ * Protected by the lock within the structure.
*/
struct timer_signal_data {
pthread_t tid; /* thread id managing signals */
int setup_done;
int qs_done;
+ pthread_mutex_t lock;
};
-static struct timer_signal_data timer_signal;
+static struct timer_signal_data timer_signal = {
+ .tid = 0,
+ .setup_done = 0,
+ .qs_done = 0,
+ .lock = PTHREAD_MUTEX_INITIALIZER,
+};
/**
* lib_ring_buffer_reset - Reset ring buffer to initial values.
handle = chan->handle;
config = &chan->backend.config;
- DBG("Timer for channel %p\n", chan);
+ DBG("Switch timer for channel %p\n", chan);
/*
* Only flush buffers periodically if readers are active.
struct lttng_ust_lib_ring_buffer *buf =
shmp(handle, chan->backend.buf[0].shmp);
- if (uatomic_read(&buf->active_readers))
- lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
- chan->handle);
+ if (uatomic_read(&buf->active_readers))
+ lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
+ chan->handle);
+ }
+ pthread_mutex_unlock(&wakeup_fd_mutex);
+ return;
+}
+
+static
+void lib_ring_buffer_channel_do_read(struct channel *chan)
+{
+ const struct lttng_ust_lib_ring_buffer_config *config;
+ struct lttng_ust_shm_handle *handle;
+ int cpu;
+
+ handle = chan->handle;
+ config = &chan->backend.config;
+
+ /*
+ * Only flush buffers periodically if readers are active.
+ */
+ pthread_mutex_lock(&wakeup_fd_mutex);
+ if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+ for_each_possible_cpu(cpu) {
+ struct lttng_ust_lib_ring_buffer *buf =
+ shmp(handle, chan->backend.buf[cpu].shmp);
+
+ if (uatomic_read(&buf->active_readers)
+ && lib_ring_buffer_poll_deliver(config, buf,
+ chan, handle)) {
+ lib_ring_buffer_wakeup(buf, handle);
+ }
+ }
+ } else {
+ struct lttng_ust_lib_ring_buffer *buf =
+ shmp(handle, chan->backend.buf[0].shmp);
+
+ if (uatomic_read(&buf->active_readers)
+ && lib_ring_buffer_poll_deliver(config, buf,
+ chan, handle)) {
+ lib_ring_buffer_wakeup(buf, handle);
+ }
}
pthread_mutex_unlock(&wakeup_fd_mutex);
+}
+
+static
+void lib_ring_buffer_channel_read_timer(int sig, siginfo_t *si, void *uc)
+{
+ struct channel *chan;
+
+ assert(CMM_LOAD_SHARED(timer_signal.tid) == pthread_self());
+ chan = si->si_value.sival_ptr;
+ DBG("Read timer for channel %p\n", chan);
+ lib_ring_buffer_channel_do_read(chan);
return;
}
if (ret) {
PERROR("sigemptyset");
}
- ret = sigaddset(mask, LTTNG_UST_RB_SIG);
+ ret = sigaddset(mask, LTTNG_UST_RB_SIG_FLUSH);
+ if (ret) {
+ PERROR("sigaddset");
+ }
+ ret = sigaddset(mask, LTTNG_UST_RB_SIG_READ);
if (ret) {
PERROR("sigaddset");
}
for (;;) {
signr = sigwaitinfo(&mask, &info);
if (signr == -1) {
- PERROR("sigwaitinfo");
+ if (errno != EINTR)
+ PERROR("sigwaitinfo");
continue;
}
- if (signr == LTTNG_UST_RB_SIG) {
+ if (signr == LTTNG_UST_RB_SIG_FLUSH) {
lib_ring_buffer_channel_switch_timer(info.si_signo,
&info, NULL);
+ } else if (signr == LTTNG_UST_RB_SIG_READ) {
+ lib_ring_buffer_channel_read_timer(info.si_signo,
+ &info, NULL);
} else if (signr == LTTNG_UST_RB_SIG_TEARDOWN) {
cmm_smp_mb();
CMM_STORE_SHARED(timer_signal.qs_done, 1);
}
/*
- * Called with ust_lock() held.
* Ensure only a single thread listens on the timer signal.
*/
static
pthread_t thread;
int ret;
+ pthread_mutex_lock(&timer_signal.lock);
if (timer_signal.setup_done)
- return;
+ goto end;
ret = pthread_create(&thread, NULL, &sig_thread, NULL);
if (ret) {
PERROR("pthread_detach");
}
timer_signal.setup_done = 1;
+end:
+ pthread_mutex_unlock(&timer_signal.lock);
}
/*
- * Called with ust_lock() held.
+ * Wait for signal-handling thread quiescent state.
*/
+static
+void lib_ring_buffer_wait_signal_thread_qs(unsigned int signr)
+{
+ sigset_t pending_set;
+ int ret;
+
+ /*
+ * We need to be the only thread interacting with the thread
+ * that manages signals for teardown synchronization.
+ */
+ pthread_mutex_lock(&timer_signal.lock);
+
+ /*
+ * Ensure we don't have any signal queued for this channel.
+ */
+ for (;;) {
+ ret = sigemptyset(&pending_set);
+ if (ret == -1) {
+ PERROR("sigemptyset");
+ }
+ ret = sigpending(&pending_set);
+ if (ret == -1) {
+ PERROR("sigpending");
+ }
+ if (!sigismember(&pending_set, signr))
+ break;
+ caa_cpu_relax();
+ }
+
+ /*
+ * From this point, no new signal handler will be fired that
+ * would try to access "chan". However, we still need to wait
+ * for any currently executing handler to complete.
+ */
+ cmm_smp_mb();
+ CMM_STORE_SHARED(timer_signal.qs_done, 0);
+ cmm_smp_mb();
+
+ /*
+ * Kill with LTTNG_UST_RB_SIG_TEARDOWN, so signal management
+ * thread wakes up.
+ */
+ kill(getpid(), LTTNG_UST_RB_SIG_TEARDOWN);
+
+ while (!CMM_LOAD_SHARED(timer_signal.qs_done))
+ caa_cpu_relax();
+ cmm_smp_mb();
+
+ pthread_mutex_unlock(&timer_signal.lock);
+}
+
static
void lib_ring_buffer_channel_switch_timer_start(struct channel *chan)
{
lib_ring_buffer_setup_timer_thread();
sev.sigev_notify = SIGEV_SIGNAL;
- sev.sigev_signo = LTTNG_UST_RB_SIG;
+ sev.sigev_signo = LTTNG_UST_RB_SIG_FLUSH;
sev.sigev_value.sival_ptr = chan;
ret = timer_create(CLOCKID, &sev, &chan->switch_timer);
if (ret == -1) {
}
}
-/*
- * Called with ust_lock() held.
- */
static
void lib_ring_buffer_channel_switch_timer_stop(struct channel *chan)
{
- sigset_t pending_set;
- int sig_is_pending, ret;
+ int ret;
if (!chan->switch_timer_interval || !chan->switch_timer_enabled)
return;
PERROR("timer_delete");
}
- /*
- * Ensure we don't have any signal queued for this channel.
- */
- for (;;) {
- ret = sigemptyset(&pending_set);
- if (ret == -1) {
- PERROR("sigemptyset");
- }
- ret = sigpending(&pending_set);
- if (ret == -1) {
- PERROR("sigpending");
- }
- sig_is_pending = sigismember(&pending_set, LTTNG_UST_RB_SIG);
- if (!sig_is_pending)
- break;
- caa_cpu_relax();
- }
-
- /*
- * From this point, no new signal handler will be fired that
- * would try to access "chan". However, we still need to wait
- * for any currently executing handler to complete.
- */
- cmm_smp_mb();
- CMM_STORE_SHARED(timer_signal.qs_done, 0);
- cmm_smp_mb();
-
- /*
- * Kill with LTTNG_UST_RB_SIG_TEARDOWN, so signal management
- * thread wakes up.
- */
- kill(getpid(), LTTNG_UST_RB_SIG_TEARDOWN);
-
- while (!CMM_LOAD_SHARED(timer_signal.qs_done))
- caa_cpu_relax();
- cmm_smp_mb();
+ lib_ring_buffer_wait_signal_thread_qs(LTTNG_UST_RB_SIG_FLUSH);
chan->switch_timer = 0;
chan->switch_timer_enabled = 0;
}
-#if 0
-/*
- * Polling timer to check the channels for data.
- */
-static void read_buffer_timer(unsigned long data)
+static
+void lib_ring_buffer_channel_read_timer_start(struct channel *chan)
{
- struct lttng_ust_lib_ring_buffer *buf = (struct lttng_ust_lib_ring_buffer *)data;
- struct channel *chan = shmp(handle, buf->backend.chan);
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
+ struct sigevent sev;
+ struct itimerspec its;
+ int ret;
- CHAN_WARN_ON(chan, !buf->backend.allocated);
+ if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
+ || !chan->read_timer_interval || chan->read_timer_enabled)
+ return;
- if (uatomic_read(&buf->active_readers))
- && lib_ring_buffer_poll_deliver(config, buf, chan)) {
- //TODO
- //wake_up_interruptible(&buf->read_wait);
- //wake_up_interruptible(&chan->read_wait);
- }
+ chan->read_timer_enabled = 1;
- //TODO
- //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- // mod_timer_pinned(&buf->read_timer,
- // jiffies + chan->read_timer_interval);
- //else
- // mod_timer(&buf->read_timer,
- // jiffies + chan->read_timer_interval);
-}
-#endif //0
+ lib_ring_buffer_setup_timer_thread();
-static void lib_ring_buffer_start_read_timer(struct lttng_ust_lib_ring_buffer *buf,
- struct lttng_ust_shm_handle *handle)
-{
- struct channel *chan = shmp(handle, buf->backend.chan);
- const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
+ sev.sigev_notify = SIGEV_SIGNAL;
+ sev.sigev_signo = LTTNG_UST_RB_SIG_READ;
+ sev.sigev_value.sival_ptr = chan;
+ ret = timer_create(CLOCKID, &sev, &chan->read_timer);
+ if (ret == -1) {
+ PERROR("timer_create");
+ }
- if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
- || !chan->read_timer_interval
- || buf->read_timer_enabled)
- return;
+ its.it_value.tv_sec = chan->read_timer_interval / 1000000;
+ its.it_value.tv_nsec = chan->read_timer_interval % 1000000;
+ its.it_interval.tv_sec = its.it_value.tv_sec;
+ its.it_interval.tv_nsec = its.it_value.tv_nsec;
- //TODO
- //init_timer(&buf->read_timer);
- //buf->read_timer.function = read_buffer_timer;
- //buf->read_timer.expires = jiffies + chan->read_timer_interval;
- //buf->read_timer.data = (unsigned long)buf;
-
- //if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
- // add_timer_on(&buf->read_timer, buf->backend.cpu);
- //else
- // add_timer(&buf->read_timer);
- buf->read_timer_enabled = 1;
+ ret = timer_settime(chan->read_timer, 0, &its, NULL);
+ if (ret == -1) {
+ PERROR("timer_settime");
+ }
}
-static void lib_ring_buffer_stop_read_timer(struct lttng_ust_lib_ring_buffer *buf,
- struct lttng_ust_shm_handle *handle)
+static
+void lib_ring_buffer_channel_read_timer_stop(struct channel *chan)
{
- struct channel *chan = shmp(handle, buf->backend.chan);
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
+ int ret;
if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
- || !chan->read_timer_interval
- || !buf->read_timer_enabled)
+ || !chan->read_timer_interval || !chan->read_timer_enabled)
return;
- //TODO
- //del_timer_sync(&buf->read_timer);
+ ret = timer_delete(chan->read_timer);
+ if (ret == -1) {
+ PERROR("timer_delete");
+ }
+
/*
* do one more check to catch data that has been written in the last
* timer period.
*/
- if (lib_ring_buffer_poll_deliver(config, buf, chan, handle)) {
- //TODO
- //wake_up_interruptible(&buf->read_wait);
- //wake_up_interruptible(&chan->read_wait);
- }
- buf->read_timer_enabled = 0;
+ lib_ring_buffer_channel_do_read(chan);
+
+ lib_ring_buffer_wait_signal_thread_qs(LTTNG_UST_RB_SIG_READ);
+
+ chan->read_timer = 0;
+ chan->read_timer_enabled = 0;
}
static void channel_unregister_notifiers(struct channel *chan,
struct lttng_ust_shm_handle *handle)
{
- const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
- int cpu;
-
lib_ring_buffer_channel_switch_timer_stop(chan);
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- for_each_possible_cpu(cpu) {
- struct lttng_ust_lib_ring_buffer *buf = shmp(handle, chan->backend.buf[cpu].shmp);
-
- lib_ring_buffer_stop_read_timer(buf, handle);
- }
- } else {
- struct lttng_ust_lib_ring_buffer *buf = shmp(handle, chan->backend.buf[0].shmp);
-
- lib_ring_buffer_stop_read_timer(buf, handle);
- }
- //channel_backend_unregister_notifiers(&chan->backend);
+ lib_ring_buffer_channel_read_timer_stop(chan);
}
static void channel_print_errors(struct channel *chan,
size_t num_subbuf, unsigned int switch_timer_interval,
unsigned int read_timer_interval)
{
- int ret, cpu;
+ int ret;
size_t shmsize, chansize;
struct channel *chan;
struct lttng_ust_shm_handle *handle;
chan->handle = handle;
chan->commit_count_mask = (~0UL >> chan->backend.num_subbuf_order);
- chan->switch_timer_interval = switch_timer_interval;
-
- //TODO
- //chan->read_timer_interval = read_timer_interval;
- //init_waitqueue_head(&chan->read_wait);
- //init_waitqueue_head(&chan->hp_wait);
+ chan->switch_timer_interval = switch_timer_interval;
+ chan->read_timer_interval = read_timer_interval;
lib_ring_buffer_channel_switch_timer_start(chan);
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- /*
- * In case of non-hotplug cpu, if the ring-buffer is allocated
- * in early initcall, it will not be notified of secondary cpus.
- * In that off case, we need to allocate for all possible cpus.
- */
- for_each_possible_cpu(cpu) {
- struct lttng_ust_lib_ring_buffer *buf = shmp(handle, chan->backend.buf[cpu].shmp);
- lib_ring_buffer_start_read_timer(buf, handle);
- }
- } else {
- struct lttng_ust_lib_ring_buffer *buf = shmp(handle, chan->backend.buf[0].shmp);
+ lib_ring_buffer_channel_read_timer_start(chan);
- lib_ring_buffer_start_read_timer(buf, handle);
- }
return handle;
error_backend_init:
}
/**
- * lib_ring_buffer_put_snapshot - move consumed counter forward
+ * lib_ring_buffer_move_consumer - move consumed counter forward
* @buf: ring buffer
* @consumed_new: new consumed count value
*/
projects / lttng-ust.git / blobdiff