Address comment: Add comments

Closes: #47419
Signed-off-by: Chi-Sheng Liu <[email protected]>

src/ray/gcs/redis_context.cc

@@ -662,7 +662,8 @@ std::unique_ptr<CallbackReply> RedisContext::RunArgvSync(
     argv.push_back(arg.data());
     argc.push_back(arg.size());
   }
-  // Run the command with exponential backoff retries.
+  // Run the command. We try to reconnect if the connection is lost, and we retry with
+  // exponential backoff using the same connection if error happens.
   auto exp_back_off = ExponentialBackOff(RayConfig::instance().redis_retry_base_ms(),
                                          RayConfig::instance().redis_retry_multiplier(),
                                          RayConfig::instance().redis_retry_max_ms());