Merge commit '8ac11a97c29ac9ce3e4099e77a9aa9475c1002b4' into 2.4

include/maxscale/routingworker.hh

@@ -240,7 +240,7 @@ public:
      *
      * @return The id of the routing worker.
      */
-    int id() const
+    int id() const override
     {
         return m_id;
     }

maxutils/maxbase/include/maxbase/worker.hh

@@ -335,6 +335,16 @@ public:
 
     virtual ~Worker();
 
+    /**
+     * Returns the id of the worker
+     *
+     * @return The address of the worker cast to an int
+     */
+    virtual int id() const
+    {
+        return (intptr_t)this;
+    }
+
     int load(Load::counter_t counter)
     {
         return m_load.percentage(counter);

maxutils/maxbase/src/messagequeue.cc

@@ -17,10 +17,12 @@
 #include <string.h>
 #include <unistd.h>
 #include <fstream>
+#include <mutex>
 #include <maxbase/assert.h>
 #include <maxbase/log.h>
 #include <maxbase/string.hh>
 #include <maxbase/worker.hh>
+#include <maxbase/format.hh>
 
 namespace
 {
@@ -146,10 +148,23 @@ MessageQueue* MessageQueue::create(Handler* pHandler)
          */
         if (fcntl(fds[0], F_SETPIPE_SZ, this_unit.pipe_max_size) == -1)
         {
-            MXB_WARNING("Failed to increase pipe buffer size to '%d': %d, %s",
-                        this_unit.pipe_max_size,
-                        errno,
-                        mxb_strerror(errno));
+            MXB_WARNING("Failed to increase pipe buffer size to '%d': %d, %s. "
+                        "Increase pipe-user-pages-soft (sysctl fs.pipe-user-pages-soft) "
+                        "or reduce pipe-max-size (sysctl fs.pipe-max-size).",
+                        this_unit.pipe_max_size, errno, mxb_strerror(errno));
+        }
+        else
+        {
+            static int current_pipe_max_size = 0;
+            static std::mutex pipe_size_lock;
+            std::lock_guard<std::mutex> guard(pipe_size_lock);
+
+            if (current_pipe_max_size == 0)
+            {
+                current_pipe_max_size = this_unit.pipe_max_size;
+                MXB_NOTICE("Worker message queue size: %s",
+                           mxb::to_binary_size(this_unit.pipe_max_size).c_str());
+            }
         }
 #endif
         pThis = new(std::nothrow) MessageQueue(pHandler, read_fd, write_fd);
@@ -219,7 +234,8 @@ bool MessageQueue::post(const Message& message) const
 
         if (n == -1)
         {
-            MXB_ERROR("Failed to write message: %d, %s", errno, mxb_strerror(errno));
+            MXB_ERROR("Failed to write message to worker %d: %d, %s",
+                      m_pWorker->id(), errno, mxb_strerror(errno));
 
             static bool warn_pipe_buffer_size = true;