[Tarantool-patches] [PATCH] Add a cancellation guard to cpipe flush callback
Leonid Vasiliev
lvasiliev at tarantool.org
Tue Dec 3 19:33:19 MSK 2019
https://github.com/tarantool/tarantool/issues/4127
https://github.com/tarantool/tarantool/tree/lvasiliev/gh-4127-WAL-thread-stucks
We need to set a thread cancellation guard, because
another thread may cancel the current thread
(write() is a cancellation point in ev_async_send)
and the activation of the ev_async watcher
through ev_async_send will fail.
---
src/lib/core/cbus.c | 13 +++++++++++++
src/tt_pthread.h | 5 +++++
2 files changed, 18 insertions(+)
diff --git a/src/lib/core/cbus.c b/src/lib/core/cbus.c
index b3b1280e7..7e9ef91e3 100644
--- a/src/lib/core/cbus.c
+++ b/src/lib/core/cbus.c
@@ -284,6 +284,17 @@ cpipe_flush_cb(ev_loop *loop, struct ev_async *watcher, int events)
/* Trigger task processing when the queue becomes non-empty. */
bool output_was_empty;
+ /*
+ * We need to set a thread cancellation guard, because
+ * another thread may cancel the current thread
+ * (write() is a cancellation point in ev_async_send)
+ * and the activation of the ev_async watcher
+ * through ev_async_send will fail.
+ */
+
+ int old_cancel_state;
+ tt_pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_cancel_state);
+
tt_pthread_mutex_lock(&endpoint->mutex);
output_was_empty = stailq_empty(&endpoint->output);
/** Flush input */
@@ -297,6 +308,8 @@ cpipe_flush_cb(ev_loop *loop, struct ev_async *watcher, int events)
ev_async_send(endpoint->consumer, &endpoint->async);
}
+
+ tt_pthread_setcancelstate(old_cancel_state, NULL);
}
void
diff --git a/src/tt_pthread.h b/src/tt_pthread.h
index 40b43b112..6bb19eb23 100644
--- a/src/tt_pthread.h
+++ b/src/tt_pthread.h
@@ -300,6 +300,11 @@
#define tt_pthread_getspecific(key) pthread_getspecific(key)
+#define tt_pthread_setcancelstate(state, oldstate) \
+({ int e__ = pthread_setcancelstate(state, oldstate);\
+ tt_pthread_error(e__); \
+})
+
/** Set the current thread's name
*/
static inline void
--
2.17.1
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