[PATCH v2 05/11] eal: force prefix for internal threads

[Thomas Monjalon <thomas@monjalon.net>]

In order to make sure all threads created in DPDK drivers and libraries
have the same prefix in their name, some wrapper functions are added
for internal use when creating a control thread or setting a thread name:
	- rte_thread_create_internal_control
	- rte_thread_set_prefixed_name

The equivalent public functions are then forbidden for internal use:
	- rte_thread_create_control
	- rte_thread_set_name

Note: the libraries and drivers conversion is done in next patches,
while doing other thread-related changes.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>

---
v2: simplify size doc + build time check of internal name size
---
 devtools/checkpatches.sh           |  8 ++++
 lib/eal/common/eal_common_thread.c | 29 +++++++++++++++
 lib/eal/include/rte_thread.h       | 59 +++++++++++++++++++++++++++++-
 lib/eal/version.map                |  2 +
 4 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
index ec9d232393..e97811192a 100755
--- a/devtools/checkpatches.sh
+++ b/devtools/checkpatches.sh
@@ -159,6 +159,14 @@ check_forbidden_additions() { # <patch>
 		-f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
 		"$1" || res=1
 
+	# forbid non-internal thread in drivers and libs
+	awk -v FOLDERS='lib drivers' \
+		-v EXPRESSIONS="rte_thread_(set_name|create_control)\\\(" \
+		-v RET_ON_FAIL=1 \
+		-v MESSAGE='Prefer rte_thread_(set_prefixed_name|create_internal_control) in lib & drivers' \
+		-f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
+		"$1" || res=1
+
 	# forbid inclusion of driver specific headers in apps and examples
 	awk -v FOLDERS='app examples' \
 		-v EXPRESSIONS='include.*_driver\\.h include.*_pmd\\.h' \
diff --git a/lib/eal/common/eal_common_thread.c b/lib/eal/common/eal_common_thread.c
index 07ac721da1..cd6e00fe8a 100644
--- a/lib/eal/common/eal_common_thread.c
+++ b/lib/eal/common/eal_common_thread.c
@@ -392,6 +392,35 @@ rte_thread_create_control(rte_thread_t *thread, const char *name,
 	return ret;
 }
 
+static void
+add_internal_prefix(char *prefixed_name, const char *name, size_t size)
+{
+	size_t prefixlen;
+
+	prefixlen = strlen(RTE_THREAD_INTERNAL_PREFIX);
+	strlcpy(prefixed_name, RTE_THREAD_INTERNAL_PREFIX, size);
+	strlcpy(prefixed_name + prefixlen, name, size - prefixlen);
+}
+
+int
+rte_thread_create_internal_control(rte_thread_t *id, const char *name,
+		rte_thread_func func, void *arg)
+{
+	char prefixed_name[RTE_THREAD_NAME_SIZE];
+
+	add_internal_prefix(prefixed_name, name, sizeof(prefixed_name));
+	return rte_thread_create_control(id, prefixed_name, func, arg);
+}
+
+void
+rte_thread_set_prefixed_name(rte_thread_t id, const char *name)
+{
+	char prefixed_name[RTE_THREAD_NAME_SIZE];
+
+	add_internal_prefix(prefixed_name, name, sizeof(prefixed_name));
+	rte_thread_set_name(id, prefixed_name);
+}
+
 int
 rte_thread_register(void)
 {
diff --git a/lib/eal/include/rte_thread.h b/lib/eal/include/rte_thread.h
index dd1f62523f..afede97bed 100644
--- a/lib/eal/include/rte_thread.h
+++ b/lib/eal/include/rte_thread.h
@@ -28,6 +28,13 @@ extern "C" {
 /* Old definition, aliased for compatibility. */
 #define RTE_MAX_THREAD_NAME_LEN RTE_THREAD_NAME_SIZE
 
+/** Thread name prefix automatically added to all internal threads. */
+#define RTE_THREAD_INTERNAL_PREFIX "dpdk-"
+/** Maximum internal thread name length (including '\0'). */
+#define RTE_THREAD_INTERNAL_NAME_SIZE 11
+RTE_BUILD_BUG_ON(RTE_THREAD_INTERNAL_NAME_SIZE !=
+	RTE_THREAD_NAME_SIZE - sizeof(RTE_THREAD_INTERNAL_PREFIX) + 1)
+
 /**
  * Thread id descriptor.
  */
@@ -112,7 +119,7 @@ int rte_thread_create(rte_thread_t *thread_id,
  * @param thread_func
  *   Function to be executed by the new thread.
  * @param arg
- *   Argument passed to start_routine.
+ *   Argument passed to thread_func.
  * @return
  *   On success, returns 0; on error, it returns a negative value
  *   corresponding to the error number.
@@ -121,6 +128,35 @@ int
 rte_thread_create_control(rte_thread_t *thread, const char *name,
 		rte_thread_func thread_func, void *arg);
 
+/**
+ * Create an internal control thread.
+ *
+ * Creates a control thread with the given name prefixed.
+ * If setting the name of the thread fails, the error is ignored and logged.
+ *
+ * The affinity of the new thread is based on the CPU affinity retrieved
+ * at the time rte_eal_init() was called, the EAL threads are then excluded.
+ *
+ * @param id
+ *   Filled with the thread ID of the new created thread.
+ * @param name
+ *   The name of the control thread.
+ *   See RTE_THREAD_INTERNAL_NAME_SIZE for maximum length.
+ *   The name of the driver or library should be first,
+ *   then followed by a hyphen and more details.
+ *   It will be prefixed with RTE_THREAD_INTERNAL_PREFIX by this function.
+ * @param func
+ *   Function to be executed by the new thread.
+ * @param arg
+ *   Argument passed to func.
+ * @return
+ *   On success, returns 0; a negative value otherwise.
+ */
+__rte_internal
+int
+rte_thread_create_internal_control(rte_thread_t *id, const char *name,
+		rte_thread_func func, void *arg);
+
 /**
  * Waits for the thread identified by 'thread_id' to terminate
  *
@@ -159,6 +195,7 @@ rte_thread_t rte_thread_self(void);
 
 /**
  * Set the name of the thread.
+ *
  * This API is a noop if the underlying platform does not
  * support setting the thread name or the platform-specific
  * API used to set the thread name fails.
@@ -173,6 +210,26 @@ rte_thread_t rte_thread_self(void);
 void
 rte_thread_set_name(rte_thread_t thread_id, const char *thread_name);
 
+/**
+ * Set the name of an internal thread with the common prefix.
+ *
+ * This API is a noop if the underlying platform does not support
+ * setting the thread name, or if it fails.
+ *
+ * @param id
+ *   The ID of the thread to set name.
+ *
+ * @param name
+ *   The name to set after being prefixed.
+ *   See RTE_THREAD_INTERNAL_NAME_SIZE for maximum length.
+ *   The name of the driver or library should be first,
+ *   then followed by a hyphen and more details.
+ *   It will be prefixed with RTE_THREAD_INTERNAL_PREFIX by this function.
+ */
+__rte_internal
+void
+rte_thread_set_prefixed_name(rte_thread_t id, const char *name);
+
 /**
  * Check if 2 thread ids are equal.
  *
diff --git a/lib/eal/version.map b/lib/eal/version.map
index 33b853d7be..6d32c19286 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -462,4 +462,6 @@ INTERNAL {
 	rte_mem_map;
 	rte_mem_page_size;
 	rte_mem_unmap;
+	rte_thread_create_internal_control;
+	rte_thread_set_prefixed_name;
 };
-- 
2.42.0