[dpdk-dev] [RFC PATCH] log: track log level changes

[David Marchand]

Add a log message when changing log levels to be sure of which logtype
is enabled.

Suggested-by: Ilya Maximets <i.maxim...@ovn.org>
Signed-off-by: David Marchand <david.march...@redhat.com>
---
Sending this as a RFC, this makes it easier to notice the problem we have
lived with so far: shared library loading do not honor log levels set on
cmdline unless it uses rte_log_register_type_and_pick_level.

---
 lib/librte_eal/common/eal_common_log.c | 56 ++++++++++++++++----------
 1 file changed, 35 insertions(+), 21 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_log.c 
b/lib/librte_eal/common/eal_common_log.c
index 8835c8fff8..24d53ed9c7 100644
--- a/lib/librte_eal/common/eal_common_log.c
+++ b/lib/librte_eal/common/eal_common_log.c
@@ -130,6 +130,37 @@ rte_log_can_log(uint32_t logtype, uint32_t level)
        return true;
 }
 
+static const char *
+loglevel_to_string(uint32_t level)
+{
+       switch (level) {
+       case 0: return "disabled";
+       case RTE_LOG_EMERG: return "emerg";
+       case RTE_LOG_ALERT: return "alert";
+       case RTE_LOG_CRIT: return "critical";
+       case RTE_LOG_ERR: return "error";
+       case RTE_LOG_WARNING: return "warning";
+       case RTE_LOG_NOTICE: return "notice";
+       case RTE_LOG_INFO: return "info";
+       case RTE_LOG_DEBUG: return "debug";
+       default: return "unknown";
+       }
+}
+
+static void
+logtype_set_level(uint32_t type, uint32_t level)
+{
+       uint32_t current = rte_logs.dynamic_types[type].loglevel;
+
+       if (current != level) {
+               rte_logs.dynamic_types[type].loglevel = level;
+               RTE_LOG(DEBUG, EAL, "%s logtype level changed from %s to %s\n",
+                       rte_logs.dynamic_types[type].name,
+                       loglevel_to_string(current),
+                       loglevel_to_string(level));
+       }
+}
+
 int
 rte_log_set_level(uint32_t type, uint32_t level)
 {
@@ -138,7 +169,7 @@ rte_log_set_level(uint32_t type, uint32_t level)
        if (level > RTE_LOG_DEBUG)
                return -1;
 
-       rte_logs.dynamic_types[type].loglevel = level;
+       logtype_set_level(type, level);
 
        return 0;
 }
@@ -161,7 +192,7 @@ rte_log_set_level_regexp(const char *regex, uint32_t level)
                        continue;
                if (regexec(&r, rte_logs.dynamic_types[i].name, 0,
                                NULL, 0) == 0)
-                       rte_logs.dynamic_types[i].loglevel = level;
+                       logtype_set_level(i, level);
        }
 
        regfree(&r);
@@ -221,7 +252,7 @@ rte_log_set_level_pattern(const char *pattern, uint32_t 
level)
                        continue;
 
                if (fnmatch(pattern, rte_logs.dynamic_types[i].name, 0) == 0)
-                       rte_logs.dynamic_types[i].loglevel = level;
+                       logtype_set_level(i, level);
        }
 
        return 0;
@@ -328,7 +359,7 @@ rte_log_register_type_and_pick_level(const char *name, 
uint32_t level_def)
                }
        }
 
-       rte_logs.dynamic_types[type].loglevel = level;
+       logtype_set_level(type, level);
 
        return type;
 }
@@ -390,23 +421,6 @@ RTE_INIT_PRIO(rte_log_init, LOG)
        rte_logs.dynamic_types_len = RTE_LOGTYPE_FIRST_EXT_ID;
 }
 
-static const char *
-loglevel_to_string(uint32_t level)
-{
-       switch (level) {
-       case 0: return "disabled";
-       case RTE_LOG_EMERG: return "emerg";
-       case RTE_LOG_ALERT: return "alert";
-       case RTE_LOG_CRIT: return "critical";
-       case RTE_LOG_ERR: return "error";
-       case RTE_LOG_WARNING: return "warning";
-       case RTE_LOG_NOTICE: return "notice";
-       case RTE_LOG_INFO: return "info";
-       case RTE_LOG_DEBUG: return "debug";
-       default: return "unknown";
-       }
-}
-
 /* dump global level and registered log types */
 void
 rte_log_dump(FILE *f)
-- 
2.23.0