logging: fix bug where links wouldn't be promptly activated

The log process thread is what activates multidomain log
links, but if all backends were already initialized,
it would enter a mode where it would block until new
local logs were ready to be processed, even if links
were not yet completed in activation. Change the logic
for computing the timeout used to block the processing
thread so that it stays in periodic polling mode if there
are still log links that haven't finished activating.

Signed-off-by: Mike J. Chen <[email protected]>

Author: mjchen0

subsys/logging/log_core.c

@@ -940,11 +940,19 @@ static void log_process_thread_func(void *dummy1, void *dummy2, void *dummy3)
 	uint32_t links_active_mask = 0xFFFFFFFF;
 	uint8_t domain_offset = 0;
 	uint32_t activate_mask = z_log_init(false, false);
-	/* If some backends are not activated yet set periodical thread wake up
-	 * to poll backends for readiness. Period is set arbitrary.
-	 * If all backends are ready periodic wake up is not needed.
-	 */
-	k_timeout_t timeout = (activate_mask != 0) ? K_MSEC(50) : K_FOREVER;
+	k_timeout_t timeout;
+	if (IS_ENABLED(CONFIG_LOG_MULTIDOMAIN)) {
+		/* when multidomain is enabled, start in periodic polling
+		 * mode to check for link readiness
+		 */
+		timeout = K_MSEC(50);
+	} else {
+		/* If some backends are not activated yet set periodical thread wake up
+		 * to poll backends for readiness. Period is set arbitrary.
+		 * If all backends are ready periodic wake up is not needed.
+		 */
+		timeout = (activate_mask != 0) ? K_MSEC(50) : K_FOREVER;
+	}
 	bool processed_any = false;
 	thread_set(k_current_get());
 
@@ -955,17 +963,32 @@ static void log_process_thread_func(void *dummy1, void *dummy2, void *dummy3)
 		if (activate_mask) {
 			activate_mask = activate_foreach_backend(activate_mask);
 			if (!activate_mask) {
-				/* Periodic wake up no longer needed since all
-				 * backends are ready.
-				 */
-				timeout = K_FOREVER;
+				if (IS_ENABLED(CONFIG_LOG_MULTIDOMAIN)) {
+					if (!links_active_mask) {
+						/* Periodic wake up no longer needed since all
+						 * backends and links are ready.
+						 */
+						timeout = K_FOREVER;
+					}
+				} else {
+					/* Periodic wake up no longer needed since all
+					 * backends are ready.
+					 */
+					timeout = K_FOREVER;
+				}
 			}
 		}
 
 		/* Keep trying to activate links until all links are active. */
 		if (IS_ENABLED(CONFIG_LOG_MULTIDOMAIN) && links_active_mask) {
 			links_active_mask =
 				z_log_links_activate(links_active_mask, &domain_offset);
+			if (!links_active_mask && !activate_mask) {
+				/* Periodic wake up no longer needed since all
+				 * backends and links are ready.
+				 */
+				timeout = K_FOREVER;
+			}
 		}