On 2016-11-04 10:22 AM, Philippe Proulx wrote:
On Fri, Nov 4, 2016 at 10:13 AM, Jonathan Rajotte Julien
<[email protected]> wrote:
Nitpicking:
Should this be RETRY_DELAY_MS since other name scheme use the *_MS suffix ?
e.g:
LTTNG_UST_RING_BUFFER_RETRY_DELAY_MS
CONFIG_LTTNG_UST_DEFAULT_BLOCKING_RETRY_TIMEOUT_MS
timeout_left_ms
Counterexample: LTTNG_UST_REGISTER_TIMEOUT.
Phil
Well we have a problem.
Jonathan
/*
* Non-static to ensure the compiler does not optimize away the xor.
@@ -149,6 +150,14 @@ static struct timer_signal_data timer_signal = {
.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.
@@ -1985,6 +1994,23 @@ void lib_ring_buffer_switch_slow(struct
lttng_ust_lib_ring_buffer *buf, enum swi
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;
+ else
+ delay = min_t(int, timeout, RETRY_DELAY);
+ (void) poll(NULL, 0, delay);
+ if (timeout > 0)
+ *timeout_left_ms -= delay;
+ return true; /* Retry. */
+}
+
/*
* Returns :
* 0 if ok
@@ -2001,6 +2027,7 @@ int lib_ring_buffer_try_reserve_slow(struct
lttng_ust_lib_ring_buffer *buf,
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);
@@ -2083,6 +2110,9 @@ retry:
>= 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.
--
Jonathan R. Julien
Efficios
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--
Jonathan R. Julien
Efficios
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