[dpdk-dev] [PATCH v4] eal: add function to check if primary proc alive

Harry van Haaren harry.van.haaren at intel.com
Tue Feb 23 15:10:12 CET 2016


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.

The RTE_MAGIC number is written to the shared config by the
primary process, this is the signal to the secondary process
that the EAL is set up, and ready to be used. The function
rte_eal_mcfg_complete() writes RTE_MAGIC. This has been
delayed in the EAL init proceedure, as the PCI probing in
the primary process can interfere with the secondary running.

Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
---

v4:
- Rebased to git head (2.3 -> 16.04 changes)

v3:
- Fixed Copyright years

v2:
- Passing NULL as const char* uses default /var/run/.rte_config
- Moved code into /common/ instead of /linuxapp/, should work on BSD now

 doc/guides/rel_notes/release_16_04.rst          |  6 +++
 lib/librte_eal/bsdapp/eal/Makefile              |  1 +
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
 lib/librte_eal/common/eal_common_proc.c         | 61 +++++++++++++++++++++++++
 lib/librte_eal/common/include/rte_eal.h         | 21 ++++++++-
 lib/librte_eal/linuxapp/eal/Makefile            |  3 +-
 lib/librte_eal/linuxapp/eal/eal.c               |  6 +--
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 8 files changed, 95 insertions(+), 5 deletions(-)
 create mode 100644 lib/librte_eal/common/eal_common_proc.c

diff --git a/doc/guides/rel_notes/release_16_04.rst b/doc/guides/rel_notes/release_16_04.rst
index 5786f74..8893ad5 100644
--- a/doc/guides/rel_notes/release_16_04.rst
+++ b/doc/guides/rel_notes/release_16_04.rst
@@ -62,6 +62,12 @@ This section should contain bug fixes added to the relevant sections. Sample for
 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 d7ca60b..1c79734 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -63,6 +63,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_alarm.c
 
 # from common dir
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_lcore.c
+SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_proc.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_log.c
diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 4f93ab7..15c0d9e 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -146,5 +146,6 @@ DPDK_2.3 {
 	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/eal_common_proc.c b/lib/librte_eal/common/eal_common_proc.c
new file mode 100644
index 0000000..c598891
--- /dev/null
+++ b/lib/librte_eal/common/eal_common_proc.c
@@ -0,0 +1,61 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright 2016 Intel Shannon Ltd. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <rte_eal.h>
+
+#include "eal_filesystem.h"
+#include "eal_internal_cfg.h"
+
+int
+rte_eal_primary_proc_alive(const char *config_file_path)
+{
+	int config_fd;
+
+	if (config_file_path)
+		config_fd = open(config_file_path, O_RDONLY);
+	else {
+		char default_path[PATH_MAX+1];
+		snprintf(default_path, PATH_MAX, RUNTIME_CONFIG_FMT,
+			 default_config_dir, "rte");
+		config_fd = open(default_path, O_RDONLY);
+	}
+	if (config_fd < 0)
+		return 0;
+
+	int ret = lockf(config_fd, F_TEST, 0);
+	close(config_fd);
+
+	return !!ret;
+}
diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
index 0e99c31..8741627 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 +156,25 @@ 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 one.
+ *  - If dead, returns zero.
+ */
+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 6e26250..713dd68 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
@@ -73,6 +73,7 @@ endif
 
 # from common dir
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_lcore.c
+SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_proc.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_log.c
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 4d3e0de..f9cdb4a 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -1,7 +1,7 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
  *   Copyright(c) 2012-2014 6WIND S.A.
  *   All rights reserved.
  *
@@ -819,8 +819,6 @@ rte_eal_init(int argc, char **argv)
 
 	eal_check_mem_on_local_socket();
 
-	rte_eal_mcfg_complete();
-
 	if (eal_plugins_init() < 0)
 		rte_panic("Cannot init plugins\n");
 
@@ -878,6 +876,8 @@ rte_eal_init(int argc, char **argv)
 	if (rte_eal_pci_probe())
 		rte_panic("Cannot probe PCI\n");
 
+	rte_eal_mcfg_complete();
+
 	return fctret;
 }
 
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index e8d8660..e31487d 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -149,5 +149,6 @@ DPDK_2.3 {
 	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



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