[dpdk-dev] [PATCH v9] app/pdump: exit with primary process

[Suanming.Mou <mousuanming@huawei.com>]

From: Suanming Mou <mousuanming@huawei.com>

The pdump tool works as the secondary process. When the primary process
exits and the residual secondary process keeps running, it will make the
primary process can't start up again. Since the ex-fbarry files are still
attached by the secondary process pdump, the 'new' primary process can't
get these files locked.

The patch is to set up an alarm which runs every 0.5s periodically
to monitor the primary process in the pdump. Once the primary exits,
so will the pdump.

Signed-off-by: Suanming Mou <mousuanming@huawei.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Vipin Varghese <vipin.varghese@intel.com>
Reviewed-by: Reshma Pattan <reshma.pattan@intel.com>
Reviewed-by: Thomas Monjalon <thomas@monjalon.net>
---
V9:
* reword the comments and update the git log.
* move release note to release_19_08.rst.
* remove dot in name.

 app/pdump/main.c                       | 46 ++++++++++++++++++++++++++++++++++
 doc/guides/rel_notes/release_19_08.rst |  3 +++
 doc/guides/tools/pdump.rst             |  2 ++
 3 files changed, 51 insertions(+)

diff --git a/app/pdump/main.c b/app/pdump/main.c
index 3d20854..859a96c 100644
--- a/app/pdump/main.c
+++ b/app/pdump/main.c
@@ -13,6 +13,7 @@
 #include <net/if.h>
 
 #include <rte_eal.h>
+#include <rte_alarm.h>
 #include <rte_common.h>
 #include <rte_debug.h>
 #include <rte_ethdev.h>
@@ -65,6 +66,8 @@
 #define SIZE 256
 #define BURST_SIZE 32
 #define NUM_VDEVS 2
+/* Maximum delay for exiting after primary process. */
+#define MONITOR_INTERVAL (500 * 1000)
 
 /* true if x is a power of 2 */
 #define POWEROF2(x) ((((x)-1) & (x)) == 0)
@@ -413,6 +416,21 @@ struct parse_val {
 }
 
 static void
+monitor_primary(void *arg __rte_unused)
+{
+	if (quit_signal)
+		return;
+
+	if (rte_eal_primary_proc_alive(NULL)) {
+		rte_eal_alarm_set(MONITOR_INTERVAL, monitor_primary, NULL);
+		return;
+	}
+
+	printf("Primary process is no longer active, exiting...\n");
+	quit_signal = 1;
+}
+
+static void
 print_pdump_stats(void)
 {
 	int i;
@@ -537,6 +555,21 @@ struct parse_val {
 }
 
 static void
+disable_primary_monitor(void)
+{
+	int ret;
+
+	/*
+	 * Cancel monitoring of primary process.
+	 * There will be no error if no alarm is set
+	 * (in case primary process kill was detected earlier).
+	 */
+	ret = rte_eal_alarm_cancel(monitor_primary, NULL);
+	if (ret < 0)
+		printf("Fail to disable monitor:%d\n", ret);
+}
+
+static void
 signal_handler(int sig_num)
 {
 	if (sig_num == SIGINT) {
@@ -910,6 +943,17 @@ struct parse_val {
 		;
 }
 
+static void
+enable_primary_monitor(void)
+{
+	int ret;
+
+	/* Once primary exits, so will pdump. */
+	ret = rte_eal_alarm_set(MONITOR_INTERVAL, monitor_primary, NULL);
+	if (ret < 0)
+		printf("Fail to enable monitor:%d\n", ret);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -953,8 +997,10 @@ struct parse_val {
 	/* create mempool, ring and vdevs info */
 	create_mp_ring_vdev();
 	enable_pdump();
+	enable_primary_monitor();
 	dump_packets();
 
+	disable_primary_monitor();
 	cleanup_pdump_resources();
 	/* dump debug stats */
 	print_pdump_stats();
diff --git a/doc/guides/rel_notes/release_19_08.rst b/doc/guides/rel_notes/release_19_08.rst
index b9510f9..e3a22e0 100644
--- a/doc/guides/rel_notes/release_19_08.rst
+++ b/doc/guides/rel_notes/release_19_08.rst
@@ -54,6 +54,9 @@ New Features
      Also, make sure to start the actual text at the margin.
      =========================================================
 
+* **Updated the pdump application.**
+
+  Add support for pdump to exit with primary process.
 
 Removed Items
 -------------
diff --git a/doc/guides/tools/pdump.rst b/doc/guides/tools/pdump.rst
index 53cd2b4..62b4a5e 100644
--- a/doc/guides/tools/pdump.rst
+++ b/doc/guides/tools/pdump.rst
@@ -26,6 +26,8 @@ a DPDK secondary process and is capable of enabling packet capture on dpdk ports
         Once the libpcap development files are installed, the libpcap based PMD
         can be enabled by setting CONFIG_RTE_LIBRTE_PMD_PCAP=y and recompiling the DPDK.
 
+      * The ``dpdk-pdump`` tool runs as a DPDK secondary process. It exits when
+        the primary application exits.
 
 Running the Application
 -----------------------
-- 
1.8.3.4