The existing definition of rte_epoll_wait retries if interrupted
by a signal. This behavior makes it hard to use rte_epoll_wait
for applications that want to use signals do do things like
exit polling loop and shutdown.
Since changing existing semantic might break applications, add
a new rte_epoll_wait_interruptible() function that does the
same thing as rte_epoll_wait but will return -1 and errno of EINTR
if it receives a signal.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
.../common/include/rte_eal_interrupts.h | 23 +++++++++
lib/librte_eal/freebsd/eal/eal_interrupts.c | 12 +++++
lib/librte_eal/linux/eal/eal_interrupts.c | 47 ++++++++++++-------
lib/librte_eal/rte_eal_version.map | 1 +
4 files changed, 65 insertions(+), 18 deletions(-)
diff --git a/lib/librte_eal/common/include/rte_eal_interrupts.h
b/lib/librte_eal/common/include/rte_eal_interrupts.h
index b370c0d26458..ac1c830f37a1 100644
--- a/lib/librte_eal/common/include/rte_eal_interrupts.h
+++ b/lib/librte_eal/common/include/rte_eal_interrupts.h
@@ -87,6 +87,7 @@ struct rte_intr_handle {
/**
* It waits for events on the epoll instance.
+ * Retries if signal received.
*
* @param epfd
* Epoll instance fd on which the caller wait for events.
@@ -105,6 +106,28 @@ int
rte_epoll_wait(int epfd, struct rte_epoll_event *events,
int maxevents, int timeout);
+/**
+ * It waits for events on the epoll instance.
+ * Does not retry if signal received.
+ *
+ * @param epfd
+ * Epoll instance fd on which the caller wait for events.
+ * @param events
+ * Memory area contains the events that will be available for the caller.
+ * @param maxevents
+ * Up to maxevents are returned, must greater than zero.
+ * @param timeout
+ * Specifying a timeout of -1 causes a block indefinitely.
+ * Specifying a timeout equal to zero cause to return immediately.
+ * @return
+ * - On success, returns the number of available event.
+ * - On failure, a negative value.
+ */
+__rte_experimental
+int
+rte_epoll_wait_interruptible(int epfd, struct rte_epoll_event *events,
+ int maxevents, int timeout);
+
/**
* It performs control operations on epoll instance referred by the epfd.
* It requests that the operation op be performed for the target fd.
diff --git a/lib/librte_eal/freebsd/eal/eal_interrupts.c
b/lib/librte_eal/freebsd/eal/eal_interrupts.c
index f6831b7902c5..d3f8fd78a1ee 100644
--- a/lib/librte_eal/freebsd/eal/eal_interrupts.c
+++ b/lib/librte_eal/freebsd/eal/eal_interrupts.c
@@ -649,6 +649,18 @@ rte_epoll_wait(int epfd, struct rte_epoll_event *events,
return -ENOTSUP;
}
+int
+rte_epoll_wait_interruptible(int epfd, struct rte_epoll_event *events,
+ int maxevents, int timeout)
+{
+ RTE_SET_USED(epfd);
+ RTE_SET_USED(events);
+ RTE_SET_USED(maxevents);
+ RTE_SET_USED(timeout);
+
+ return -ENOTSUP;
+}
+
int
rte_epoll_ctl(int epfd, int op, int fd, struct rte_epoll_event *event)
{
diff --git a/lib/librte_eal/linux/eal/eal_interrupts.c
b/lib/librte_eal/linux/eal/eal_interrupts.c
index 1955324d3045..b6ae12a282e7 100644
--- a/lib/librte_eal/linux/eal/eal_interrupts.c
+++ b/lib/librte_eal/linux/eal/eal_interrupts.c
@@ -1239,9 +1239,9 @@ rte_intr_tls_epfd(void)
return RTE_PER_LCORE(_epfd);
}
-int
-rte_epoll_wait(int epfd, struct rte_epoll_event *events,
- int maxevents, int timeout)
+static int
+eal_epoll_wait(int epfd, struct rte_epoll_event *events,
+ int maxevents, int timeout, bool interruptible)
{
struct epoll_event evs[maxevents];
int rc;
@@ -1255,29 +1255,40 @@ rte_epoll_wait(int epfd, struct rte_epoll_event *events,
if (epfd == RTE_EPOLL_PER_THREAD)
epfd = rte_intr_tls_epfd();
- while (1) {
- rc = epoll_wait(epfd, evs, maxevents, timeout);
- if (likely(rc > 0)) {
- /* epoll_wait has at least one fd ready to read */
- rc = eal_epoll_process_event(evs, rc, events);
- break;
- } else if (rc < 0) {
- if (errno == EINTR)
- continue;
+retry:
+ rc = epoll_wait(epfd, evs, maxevents, timeout);
+ if (likely(rc > 0)) {
+ /* epoll_wait has at least one fd ready to read */
+ rc = eal_epoll_process_event(evs, rc, events);
+ } else if (rc < 0) {
+ if (errno == EINTR) {
+ if (!interruptible)
+ goto retry;
+ } else {
/* epoll_wait fail */
- RTE_LOG(ERR, EAL, "epoll_wait returns with fail %s\n",
+ RTE_LOG(ERR, EAL,
+ "epoll_wait returns with fail %s\n",
strerror(errno));
- rc = -1;
- break;
- } else {
- /* rc == 0, epoll_wait timed out */
- break;
}
}
return rc;
}
+int
+rte_epoll_wait(int epfd, struct rte_epoll_event *events,
+ int maxevents, int timeout)
+{
+ return eal_epoll_wait(epfd, events, maxevents, timeout, false);
+}
+
+int
+rte_epoll_wait_interruptible(int epfd, struct rte_epoll_event *events,
+ int maxevents, int timeout)
+{
+ return eal_epoll_wait(epfd, events, maxevents, timeout, true);
+}
+
static inline void
eal_epoll_data_safe_free(struct rte_epoll_event *ev)
{
diff --git a/lib/librte_eal/rte_eal_version.map
b/lib/librte_eal/rte_eal_version.map
index 234487787994..e1aeb99ba9c8 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -331,6 +331,7 @@ EXPERIMENTAL {
rte_dev_hotplug_handle_enable;
rte_dev_iterator_init;
rte_dev_iterator_next;
+ rte_epoll_wait_interruptible;
rte_extmem_attach;
rte_extmem_detach;
rte_extmem_register;
--
2.20.1
