#include <fcntl.h>
#include <signal.h>
#include <time.h>
+#include <stdbool.h>
#include <urcu/compiler.h>
#include <urcu/ref.h>
#include <urcu/tls-compat.h>
#include "backend.h"
#include "frontend.h"
#include "shm.h"
-#include "tlsfixup.h"
+#include "rb-init.h"
#include "../liblttng-ust/compat.h" /* For ENODATA */
/* Print DBG() messages about events lost only every 1048576 hits */
#define CLOCKID CLOCK_MONOTONIC
#define LTTNG_UST_RING_BUFFER_GET_RETRY 10
#define LTTNG_UST_RING_BUFFER_RETRY_DELAY_MS 10
+#define RETRY_DELAY_MS 100 /* 100 ms. */
/*
* Non-static to ensure the compiler does not optimize away the xor.
.lock = PTHREAD_MUTEX_INITIALIZER,
};
+int lttng_ust_blocking_retry_timeout =
+ CONFIG_LTTNG_UST_DEFAULT_BLOCKING_RETRY_TIMEOUT_MS;
+
+void lttng_ust_ringbuffer_set_retry_timeout(int timeout)
+{
+ lttng_ust_blocking_retry_timeout = timeout;
+}
+
/**
* lib_ring_buffer_reset - Reset ring buffer to initial values.
* @buf: Ring buffer.
chan = shmp(handle, buf->backend.chan);
if (!chan)
- abort();
+ return;
config = &chan->backend.config;
/*
* Reset iterator first. It will put the subbuffer if it currently holds
*/
v_set(config, &buf->offset, 0);
for (i = 0; i < chan->backend.num_subbuf; i++) {
- v_set(config, &shmp_index(handle, buf->commit_hot, i)->cc, 0);
- v_set(config, &shmp_index(handle, buf->commit_hot, i)->seq, 0);
- v_set(config, &shmp_index(handle, buf->commit_cold, i)->cc_sb, 0);
+ struct commit_counters_hot *cc_hot;
+ struct commit_counters_cold *cc_cold;
+
+ cc_hot = shmp_index(handle, buf->commit_hot, i);
+ if (!cc_hot)
+ return;
+ cc_cold = shmp_index(handle, buf->commit_cold, i);
+ if (!cc_cold)
+ return;
+ v_set(config, &cc_hot->cc, 0);
+ v_set(config, &cc_hot->seq, 0);
+ v_set(config, &cc_cold->cc_sb, 0);
}
uatomic_set(&buf->consumed, 0);
uatomic_set(&buf->record_disabled, 0);
{
const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config;
struct channel *chan = caa_container_of(chanb, struct channel, backend);
+ struct lttng_ust_lib_ring_buffer_backend_subbuffer *wsb;
+ struct channel *shmp_chan;
+ struct commit_counters_hot *cc_hot;
void *priv = channel_get_private(chan);
size_t subbuf_header_size;
uint64_t tsc;
*/
subbuf_header_size = config->cb.subbuffer_header_size();
v_set(config, &buf->offset, subbuf_header_size);
- subbuffer_id_clear_noref(config, &shmp_index(handle, buf->backend.buf_wsb, 0)->id);
- tsc = config->cb.ring_buffer_clock_read(shmp(handle, buf->backend.chan));
+ wsb = shmp_index(handle, buf->backend.buf_wsb, 0);
+ if (!wsb) {
+ ret = -EPERM;
+ goto free_chanbuf;
+ }
+ subbuffer_id_clear_noref(config, &wsb->id);
+ shmp_chan = shmp(handle, buf->backend.chan);
+ if (!shmp_chan) {
+ ret = -EPERM;
+ goto free_chanbuf;
+ }
+ tsc = config->cb.ring_buffer_clock_read(shmp_chan);
config->cb.buffer_begin(buf, tsc, 0, handle);
- v_add(config, subbuf_header_size, &shmp_index(handle, buf->commit_hot, 0)->cc);
- v_add(config, subbuf_header_size, &shmp_index(handle, buf->commit_hot, 0)->seq);
+ cc_hot = shmp_index(handle, buf->commit_hot, 0);
+ if (!cc_hot) {
+ ret = -EPERM;
+ goto free_chanbuf;
+ }
+ v_add(config, subbuf_header_size, &cc_hot->cc);
+ v_add(config, subbuf_header_size, &cc_hot->seq);
if (config->cb.buffer_create) {
ret = config->cb.buffer_create(buf, priv, cpu, chanb->name, handle);
shmp(handle, chan->backend.buf[cpu].shmp);
if (!buf)
- abort();
+ goto end;
if (uatomic_read(&buf->active_readers))
lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
chan->handle);
shmp(handle, chan->backend.buf[0].shmp);
if (!buf)
- abort();
+ goto end;
if (uatomic_read(&buf->active_readers))
lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
chan->handle);
}
+end:
pthread_mutex_unlock(&wakeup_fd_mutex);
return;
}
struct lttng_ust_shm_handle *handle)
{
unsigned long consumed_old, consumed_idx, commit_count, write_offset;
+ struct commit_counters_cold *cc_cold;
consumed_old = uatomic_read(&buf->consumed);
consumed_idx = subbuf_index(consumed_old, chan);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_cold, consumed_idx)->cc_sb);
+ cc_cold = shmp_index(handle, buf->commit_cold, consumed_idx);
+ if (!cc_cold)
+ return 0;
+ commit_count = v_read(config, &cc_cold->cc_sb);
/*
* No memory barrier here, since we are only interested
* in a statistically correct polling result. The next poll will
shmp(handle, chan->backend.buf[cpu].shmp);
if (!buf)
- abort();
+ goto end;
if (uatomic_read(&buf->active_readers)
&& lib_ring_buffer_poll_deliver(config, buf,
chan, handle)) {
shmp(handle, chan->backend.buf[0].shmp);
if (!buf)
- abort();
+ goto end;
if (uatomic_read(&buf->active_readers)
&& lib_ring_buffer_poll_deliver(config, buf,
chan, handle)) {
lib_ring_buffer_wakeup(buf, handle);
}
}
+end:
pthread_mutex_unlock(&wakeup_fd_mutex);
}
for_each_possible_cpu(cpu) {
struct lttng_ust_lib_ring_buffer *buf =
shmp(handle, chan->backend.buf[cpu].shmp);
- lib_ring_buffer_print_errors(chan, buf, cpu, handle);
+ if (buf)
+ lib_ring_buffer_print_errors(chan, buf, cpu, handle);
}
} else {
struct lttng_ust_lib_ring_buffer *buf =
shmp(handle, chan->backend.buf[0].shmp);
- lib_ring_buffer_print_errors(chan, buf, -1, handle);
+ if (buf)
+ lib_ring_buffer_print_errors(chan, buf, -1, handle);
}
}
static void channel_free(struct channel *chan,
- struct lttng_ust_shm_handle *handle)
+ struct lttng_ust_shm_handle *handle,
+ int consumer)
{
channel_backend_free(&chan->backend, handle);
/* chan is freed by shm teardown */
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, consumer);
free(handle);
}
error_backend_init:
error_append:
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, 1);
error_table_alloc:
free(handle);
return NULL;
return handle;
error_table_object:
- shm_object_table_destroy(handle->table);
+ shm_object_table_destroy(handle->table, 0);
error_table_alloc:
free(handle);
return NULL;
}
static
-void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle)
+void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle,
+ int consumer)
{
- channel_free(chan, handle);
+ channel_free(chan, handle, consumer);
}
/**
* sessiond/consumer are keeping a reference on the shm file
* descriptor directly. No need to refcount.
*/
- channel_release(chan, handle);
+ channel_release(chan, handle, consumer);
return;
}
{
struct channel *chan = shmp(handle, buf->backend.chan);
+ if (!chan)
+ return;
CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
cmm_smp_mb();
uatomic_dec(&buf->active_readers);
unsigned long *consumed, unsigned long *produced,
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;
+ struct channel *chan;
+ const struct lttng_ust_lib_ring_buffer_config *config;
unsigned long consumed_cur, write_offset;
int finalized;
+ chan = shmp(handle, buf->backend.chan);
+ if (!chan)
+ return -EPERM;
+ config = &chan->backend.config;
finalized = CMM_ACCESS_ONCE(buf->finalized);
/*
* Read finalized before counters.
return -EAGAIN;
}
+/**
+ * Performs the same function as lib_ring_buffer_snapshot(), but the positions
+ * are saved regardless of whether the consumed and produced positions are
+ * in the same subbuffer.
+ * @buf: ring buffer
+ * @consumed: consumed byte count indicating the last position read
+ * @produced: produced byte count indicating the last position written
+ *
+ * This function is meant to provide information on the exact producer and
+ * consumer positions without regard for the "snapshot" feature.
+ */
+int lib_ring_buffer_snapshot_sample_positions(
+ struct lttng_ust_lib_ring_buffer *buf,
+ unsigned long *consumed, unsigned long *produced,
+ struct lttng_ust_shm_handle *handle)
+{
+ struct channel *chan;
+ const struct lttng_ust_lib_ring_buffer_config *config;
+
+ chan = shmp(handle, buf->backend.chan);
+ if (!chan)
+ return -EPERM;
+ config = &chan->backend.config;
+ cmm_smp_rmb();
+ *consumed = uatomic_read(&buf->consumed);
+ /*
+ * No need to issue a memory barrier between consumed count read and
+ * write offset read, because consumed count can only change
+ * concurrently in overwrite mode, and we keep a sequence counter
+ * identifier derived from the write offset to check we are getting
+ * the same sub-buffer we are expecting (the sub-buffers are atomically
+ * "tagged" upon writes, tags are checked upon read).
+ */
+ *produced = v_read(config, &buf->offset);
+ return 0;
+}
+
/**
* lib_ring_buffer_move_consumer - move consumed counter forward
* @buf: ring buffer
struct lttng_ust_shm_handle *handle)
{
struct lttng_ust_lib_ring_buffer_backend *bufb = &buf->backend;
- struct channel *chan = shmp(handle, bufb->chan);
+ struct channel *chan;
unsigned long consumed;
+ chan = shmp(handle, bufb->chan);
+ if (!chan)
+ return;
CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
/*
unsigned long consumed,
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;
+ struct channel *chan;
+ const struct lttng_ust_lib_ring_buffer_config *config;
unsigned long consumed_cur, consumed_idx, commit_count, write_offset;
int ret, finalized, nr_retry = LTTNG_UST_RING_BUFFER_GET_RETRY;
+ struct commit_counters_cold *cc_cold;
+ chan = shmp(handle, buf->backend.chan);
+ if (!chan)
+ return -EPERM;
+ config = &chan->backend.config;
retry:
finalized = CMM_ACCESS_ONCE(buf->finalized);
/*
cmm_smp_rmb();
consumed_cur = uatomic_read(&buf->consumed);
consumed_idx = subbuf_index(consumed, chan);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_cold, consumed_idx)->cc_sb);
+ cc_cold = shmp_index(handle, buf->commit_cold, consumed_idx);
+ if (!cc_cold)
+ return -EPERM;
+ commit_count = v_read(config, &cc_cold->cc_sb);
/*
* Make sure we read the commit count before reading the buffer
* data and the write offset. Correct consumed offset ordering
struct lttng_ust_shm_handle *handle)
{
struct lttng_ust_lib_ring_buffer_backend *bufb = &buf->backend;
- struct channel *chan = shmp(handle, bufb->chan);
- const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
- unsigned long read_sb_bindex, consumed_idx, consumed;
+ struct channel *chan;
+ const struct lttng_ust_lib_ring_buffer_config *config;
+ unsigned long sb_bindex, consumed_idx, consumed;
+ struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
+ struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
+ chan = shmp(handle, bufb->chan);
+ if (!chan)
+ return;
+ config = &chan->backend.config;
CHAN_WARN_ON(chan, uatomic_read(&buf->active_readers) != 1);
if (!buf->get_subbuf) {
* Can be below zero if an iterator is used on a snapshot more than
* once.
*/
- read_sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
- v_add(config, v_read(config,
- &shmp(handle, shmp_index(handle, bufb->array, read_sb_bindex)->shmp)->records_unread),
- &bufb->records_read);
- v_set(config, &shmp(handle, shmp_index(handle, bufb->array, read_sb_bindex)->shmp)->records_unread, 0);
+ sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
+ rpages = shmp_index(handle, bufb->array, sb_bindex);
+ if (!rpages)
+ return;
+ backend_pages = shmp(handle, rpages->shmp);
+ if (!backend_pages)
+ return;
+ v_add(config, v_read(config, &backend_pages->records_unread),
+ &bufb->records_read);
+ v_set(config, &backend_pages->records_unread, 0);
CHAN_WARN_ON(chan, config->mode == RING_BUFFER_OVERWRITE
&& subbuffer_id_is_noref(config, bufb->buf_rsb.id));
subbuffer_id_set_noref(config, &bufb->buf_rsb.id);
{
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
unsigned long cons_idx, commit_count, commit_count_sb;
+ struct commit_counters_hot *cc_hot;
+ struct commit_counters_cold *cc_cold;
cons_idx = subbuf_index(cons_offset, chan);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, cons_idx)->cc);
- commit_count_sb = v_read(config, &shmp_index(handle, buf->commit_cold, cons_idx)->cc_sb);
+ cc_hot = shmp_index(handle, buf->commit_hot, cons_idx);
+ if (!cc_hot)
+ return;
+ cc_cold = shmp_index(handle, buf->commit_cold, cons_idx);
+ if (!cc_cold)
+ return;
+ commit_count = v_read(config, &cc_hot->cc);
+ commit_count_sb = v_read(config, &cc_cold->cc_sb);
if (subbuf_offset(commit_count, chan) != 0)
DBG("ring buffer %s, cpu %d: "
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
unsigned long oldidx = subbuf_index(offsets->old, chan);
unsigned long commit_count;
+ struct commit_counters_hot *cc_hot;
config->cb.buffer_begin(buf, tsc, oldidx, handle);
* determine that the subbuffer is full.
*/
cmm_smp_wmb();
+ cc_hot = shmp_index(handle, buf->commit_hot, oldidx);
+ if (!cc_hot)
+ return;
v_add(config, config->cb.subbuffer_header_size(),
- &shmp_index(handle, buf->commit_hot, oldidx)->cc);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, oldidx)->cc);
+ &cc_hot->cc);
+ commit_count = v_read(config, &cc_hot->cc);
/* Check if the written buffer has to be delivered */
lib_ring_buffer_check_deliver(config, buf, chan, offsets->old,
commit_count, oldidx, handle, tsc);
- lib_ring_buffer_write_commit_counter(config, buf, chan, oldidx,
+ lib_ring_buffer_write_commit_counter(config, buf, chan,
offsets->old + config->cb.subbuffer_header_size(),
- commit_count, handle);
+ commit_count, handle, cc_hot);
}
/*
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
unsigned long oldidx = subbuf_index(offsets->old - 1, chan);
unsigned long commit_count, padding_size, data_size;
+ struct commit_counters_hot *cc_hot;
data_size = subbuf_offset(offsets->old - 1, chan) + 1;
padding_size = chan->backend.subbuf_size - data_size;
* determine that the subbuffer is full.
*/
cmm_smp_wmb();
- v_add(config, padding_size, &shmp_index(handle, buf->commit_hot, oldidx)->cc);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, oldidx)->cc);
+ cc_hot = shmp_index(handle, buf->commit_hot, oldidx);
+ if (!cc_hot)
+ return;
+ v_add(config, padding_size, &cc_hot->cc);
+ commit_count = v_read(config, &cc_hot->cc);
lib_ring_buffer_check_deliver(config, buf, chan, offsets->old - 1,
commit_count, oldidx, handle, tsc);
- lib_ring_buffer_write_commit_counter(config, buf, chan, oldidx,
- offsets->old + padding_size, commit_count, handle);
+ lib_ring_buffer_write_commit_counter(config, buf, chan,
+ offsets->old + padding_size, commit_count, handle,
+ cc_hot);
}
/*
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
unsigned long beginidx = subbuf_index(offsets->begin, chan);
unsigned long commit_count;
+ struct commit_counters_hot *cc_hot;
config->cb.buffer_begin(buf, tsc, beginidx, handle);
* determine that the subbuffer is full.
*/
cmm_smp_wmb();
- v_add(config, config->cb.subbuffer_header_size(),
- &shmp_index(handle, buf->commit_hot, beginidx)->cc);
- commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, beginidx)->cc);
+ cc_hot = shmp_index(handle, buf->commit_hot, beginidx);
+ if (!cc_hot)
+ return;
+ v_add(config, config->cb.subbuffer_header_size(), &cc_hot->cc);
+ commit_count = v_read(config, &cc_hot->cc);
/* Check if the written buffer has to be delivered */
lib_ring_buffer_check_deliver(config, buf, chan, offsets->begin,
commit_count, beginidx, handle, tsc);
- lib_ring_buffer_write_commit_counter(config, buf, chan, beginidx,
+ lib_ring_buffer_write_commit_counter(config, buf, chan,
offsets->begin + config->cb.subbuffer_header_size(),
- commit_count, handle);
+ commit_count, handle, cc_hot);
}
/*
if (caa_unlikely(off == 0)) {
unsigned long sb_index, commit_count;
+ struct commit_counters_cold *cc_cold;
/*
* We are performing a SWITCH_FLUSH. There may be concurrent
/* Test new buffer integrity */
sb_index = subbuf_index(offsets->begin, chan);
- commit_count = v_read(config,
- &shmp_index(handle, buf->commit_cold,
- sb_index)->cc_sb);
+ cc_cold = shmp_index(handle, buf->commit_cold, sb_index);
+ if (!cc_cold)
+ return -1;
+ commit_count = v_read(config, &cc_cold->cc_sb);
reserve_commit_diff =
(buf_trunc(offsets->begin, chan)
>> chan->backend.num_subbuf_order)
void lib_ring_buffer_switch_slow(struct lttng_ust_lib_ring_buffer *buf, enum switch_mode mode,
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;
+ struct channel *chan;
+ const struct lttng_ust_lib_ring_buffer_config *config;
struct switch_offsets offsets;
unsigned long oldidx;
uint64_t tsc;
+ chan = shmp(handle, buf->backend.chan);
+ if (!chan)
+ return;
+ config = &chan->backend.config;
+
offsets.size = 0;
/*
lib_ring_buffer_switch_old_end(buf, chan, &offsets, tsc, handle);
}
+static
+bool handle_blocking_retry(int *timeout_left_ms)
+{
+ int timeout = *timeout_left_ms, delay;
+
+ if (caa_likely(!timeout))
+ return false; /* Do not retry, discard event. */
+ if (timeout < 0) /* Wait forever. */
+ delay = RETRY_DELAY_MS;
+ else
+ delay = min_t(int, timeout, RETRY_DELAY_MS);
+ (void) poll(NULL, 0, delay);
+ if (timeout > 0)
+ *timeout_left_ms -= delay;
+ return true; /* Retry. */
+}
+
/*
* Returns :
* 0 if ok
int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan,
struct switch_offsets *offsets,
- struct lttng_ust_lib_ring_buffer_ctx *ctx)
+ struct lttng_ust_lib_ring_buffer_ctx *ctx,
+ void *client_ctx)
{
const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
struct lttng_ust_shm_handle *handle = ctx->handle;
unsigned long reserve_commit_diff, offset_cmp;
+ int timeout_left_ms = lttng_ust_blocking_retry_timeout;
retry:
offsets->begin = offset_cmp = v_read(config, &buf->offset);
offsets->size = config->cb.record_header_size(config, chan,
offsets->begin,
&offsets->pre_header_padding,
- ctx);
+ ctx, client_ctx);
offsets->size +=
lib_ring_buffer_align(offsets->begin + offsets->size,
ctx->largest_align)
}
if (caa_unlikely(offsets->switch_new_start)) {
unsigned long sb_index, commit_count;
+ struct commit_counters_cold *cc_cold;
/*
* We are typically not filling the previous buffer completely.
* are not seen reordered when updated by another CPU.
*/
cmm_smp_rmb();
- commit_count = v_read(config,
- &shmp_index(handle, buf->commit_cold,
- sb_index)->cc_sb);
+ cc_cold = shmp_index(handle, buf->commit_cold, sb_index);
+ if (!cc_cold)
+ return -1;
+ commit_count = v_read(config, &cc_cold->cc_sb);
/* Read buf->commit_cold[sb_index].cc_sb before buf->offset. */
cmm_smp_rmb();
if (caa_unlikely(offset_cmp != v_read(config, &buf->offset))) {
>= chan->backend.buf_size)) {
unsigned long nr_lost;
+ if (handle_blocking_retry(&timeout_left_ms))
+ goto retry;
+
/*
* We do not overwrite non consumed buffers
* and we are full : record is lost.
config->cb.record_header_size(config, chan,
offsets->begin,
&offsets->pre_header_padding,
- ctx);
+ ctx, client_ctx);
offsets->size +=
lib_ring_buffer_align(offsets->begin + offsets->size,
ctx->largest_align)
* -EIO for other errors, else returns 0.
* It will take care of sub-buffer switching.
*/
-int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
+int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+ void *client_ctx)
{
struct channel *chan = ctx->chan;
struct lttng_ust_shm_handle *handle = ctx->handle;
buf = shmp(handle, chan->backend.buf[ctx->cpu].shmp);
else
buf = shmp(handle, chan->backend.buf[0].shmp);
+ if (!buf)
+ return -EIO;
ctx->buf = buf;
offsets.size = 0;
do {
ret = lib_ring_buffer_try_reserve_slow(buf, chan, &offsets,
- ctx);
+ ctx, client_ctx);
if (caa_unlikely(ret))
return ret;
} while (caa_unlikely(v_cmpxchg(config, &buf->offset, offsets.old,
unsigned long idx,
struct lttng_ust_shm_handle *handle)
{
- if (config->oops == RING_BUFFER_OOPS_CONSISTENCY)
- v_set(config, &shmp_index(handle, buf->commit_hot, idx)->seq, commit_count);
+ struct commit_counters_hot *cc_hot;
+
+ if (config->oops != RING_BUFFER_OOPS_CONSISTENCY)
+ return;
+ cc_hot = shmp_index(handle, buf->commit_hot, idx);
+ if (!cc_hot)
+ return;
+ v_set(config, &cc_hot->seq, commit_count);
}
+/*
+ * The ring buffer can count events recorded and overwritten per buffer,
+ * but it is disabled by default due to its performance overhead.
+ */
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
+static
+void deliver_count_events(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
+ unsigned long idx,
+ struct lttng_ust_shm_handle *handle)
+{
+ v_add(config, subbuffer_get_records_count(config,
+ &buf->backend, idx, handle),
+ &buf->records_count);
+ v_add(config, subbuffer_count_records_overrun(config,
+ &buf->backend, idx, handle),
+ &buf->records_overrun);
+}
+#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */
+static
+void deliver_count_events(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
+ unsigned long idx,
+ struct lttng_ust_shm_handle *handle)
+{
+}
+#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */
+
void lib_ring_buffer_check_deliver_slow(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan,
{
unsigned long old_commit_count = commit_count
- chan->backend.subbuf_size;
+ struct commit_counters_cold *cc_cold;
/*
* If we succeeded at updating cc_sb below, we are the subbuffer
* commit_cold cc_sb update.
*/
cmm_smp_wmb();
- if (caa_likely(v_cmpxchg(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
+ cc_cold = shmp_index(handle, buf->commit_cold, idx);
+ if (!cc_cold)
+ return;
+ if (caa_likely(v_cmpxchg(config, &cc_cold->cc_sb,
old_commit_count, old_commit_count + 1)
== old_commit_count)) {
/*
* and any other writer trying to access this subbuffer
* in this state is required to drop records.
*/
- v_add(config,
- subbuffer_get_records_count(config,
- &buf->backend,
- idx, handle),
- &buf->records_count);
- v_add(config,
- subbuffer_count_records_overrun(config,
- &buf->backend,
- idx, handle),
- &buf->records_overrun);
+ deliver_count_events(config, buf, idx, handle);
config->cb.buffer_end(buf, tsc, idx,
lib_ring_buffer_get_data_size(config,
buf,
*/
cmm_smp_mb();
/* End of exclusive subbuffer access */
- v_set(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
- commit_count);
+ v_set(config, &cc_cold->cc_sb, commit_count);
/*
* Order later updates to reserve count after
* the commit cold cc_sb update.
projects / lttng-ust.git / blobdiff