[dpdk-dev] [PATCH v7 2/2] eal: add function to check if primary proc alive

[Harry van Haaren]

This patch adds a new function to the EAL API:
int rte_eal_primary_proc_alive(const char *path);

The function indicates if a primary process is alive right now.
This functionality is implemented by testing for a write-
lock on the config file, and the function tests for a lock.

The use case for this functionality is that a secondary
process can wait until a primary process starts by polling
the function and waiting. When the primary is running, the
secondary continues to poll to detect if the primary process
has quit unexpectedly, the secondary process can detect this.

Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
Acked-by: Maryam Tahhan <maryam.tahhan at intel.com>
---
 doc/guides/rel_notes/release_16_04.rst          |  8 ++++++++
 lib/librte_eal/bsdapp/eal/Makefile              |  1 +
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
 lib/librte_eal/common/include/rte_eal.h         | 20 +++++++++++++++++++-
 lib/librte_eal/linuxapp/eal/Makefile            |  3 ++-
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 6 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/doc/guides/rel_notes/release_16_04.rst b/doc/guides/rel_notes/release_16_04.rst
index 24f15bf..7d5000f 100644
--- a/doc/guides/rel_notes/release_16_04.rst
+++ b/doc/guides/rel_notes/release_16_04.rst
@@ -74,6 +74,14 @@ EAL
 ~~~
 
 
+* **Added rte_eal_primary_proc_alive() function**
+
+  A new function ``rte_eal_primary_proc_alive()`` has been added
+  to allow the user to detect if a primary process is running.
+  Use cases for this feature include fault detection, and monitoring
+  using secondary processes.
+
+
 Drivers
 ~~~~~~~
 
diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
index 9015516..9ecf429 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -79,6 +79,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_devargs.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_dev.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_options.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_thread.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_proc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += rte_malloc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += malloc_elem.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += malloc_heap.c
diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 0c24223..58c2951 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -148,5 +148,6 @@ DPDK_16.04 {
 	rte_eal_pci_ioport_write;
 	rte_eal_pci_map_device;
 	rte_eal_pci_unmap_device;
+	rte_eal_primary_proc_alive;
 
 } DPDK_2.2;
diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
index 0e99c31..a71d6f5 100644
--- a/lib/librte_eal/common/include/rte_eal.h
+++ b/lib/librte_eal/common/include/rte_eal.h
@@ -1,7 +1,7 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
  *   All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
@@ -156,6 +156,24 @@ int rte_eal_iopl_init(void);
  *   - On failure, a negative error value.
  */
 int rte_eal_init(int argc, char **argv);
+
+/**
+ * Check if a primary process is currently alive
+ *
+ * This function returns true when a primary process is currently
+ * active.
+ *
+ * @param config_file_path
+ *   The config_file_path argument provided should point at the location
+ *   that the primary process will create its config file. If NULL, the default
+ *   config file path is used.
+ *
+ * @return
+ *  - If alive, returns 1.
+ *  - If dead, returns 0.
+ */
+int rte_eal_primary_proc_alive(const char *config_file_path);
+
 /**
  * Usage function typedef used by the application usage function.
  *
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index c5490e4..d72f035 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -1,6 +1,6 @@
 #   BSD LICENSE
 #
-#   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
+#   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
 #   All rights reserved.
 #
 #   Redistribution and use in source and binary forms, with or without
@@ -89,6 +89,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_devargs.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_dev.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_options.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_thread.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_proc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += rte_malloc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += malloc_elem.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += malloc_heap.c
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index 4aa9de7..12503ef 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -151,5 +151,6 @@ DPDK_16.04 {
 	rte_eal_pci_ioport_write;
 	rte_eal_pci_map_device;
 	rte_eal_pci_unmap_device;
+	rte_eal_primary_proc_alive;
 
 } DPDK_2.2;
-- 
2.5.0