Don't abort InnoDB/XtraDB if one can't allocate resources for AIO

- Better error messages

This fixes that one again can run the test systems with many threads without having to increase fs.aio-max-nr.


mysql-test/include/mtr_check.sql:
  Ignore the INNODB_USE_NATIVE_AIO variable (may change during execution)
mysql-test/mysql-test-run.pl:
  Ignore warnings for failure to setup AIO
storage/innobase/os/os0file.c:
  Continue without AIO even if we can't allocate resources for AIO
storage/xtradb/os/os0file.c:
  Continue without AIO even if we can't allocate resources for AIO
storage/xtradb/srv/srv0start.c:
  Give an error message (instead of core dump) if AIO can't be initialized

mysql-test/include/mtr_check.sql

@@ -30,6 +30,7 @@ BEGIN
     WHERE variable_name NOT IN ('timestamp', 'innodb_file_format_max')
      AND variable_name not like "Last_IO_Err*"
      AND variable_name != 'INNODB_IBUF_MAX_SIZE'
+     AND variable_name != 'INNODB_USE_NATIVE_AIO'
    ORDER BY variable_name;
 
   -- Dump all databases, there should be none

mysql-test/mysql-test-run.pl

@@ -4738,6 +4738,9 @@ sub extract_warning_lines ($$) {
      qr|Aborted connection|,
      qr|table.*is full|,
      qr|Linux Native AIO|, # warning that aio does not work on /dev/shm
+     qr|Error: io_setup\(\) failed|,
+     qr|Warning: io_setup\(\) failed|,
+     qr|Warning: io_setup\(\) attempt|,
     );
 
   my $matched_lines= [];

storage/innobase/os/os0file.c

@@ -3361,12 +3361,23 @@ os_aio_array_create(
 		if (!os_aio_linux_create_io_ctx(n/n_segments,
 					   &array->aio_ctx[i])) {
 			/* If something bad happened during aio setup
-			we should call it a day and return right away.
-			We don't care about any leaks because a failure
-			to initialize the io subsystem means that the
-			server (or atleast the innodb storage engine)
-			is not going to startup. */
-			return(NULL);
+			we disable linux native aio.
+                        The disadvantage will be a small memory leak
+                        at shutdown but that's ok compared to a crash
+                        or a not working server.
+                        This frequently happens when running the test suite
+                        with many threads on a system with low fs.aio-max-nr!
+                        */
+
+                        fprintf(stderr,
+                                "  InnoDB: Warning: Linux Native AIO disabled "
+                                "because os_aio_linux_create_io_ctx() "
+                                "failed. To get rid of this warning you can "
+                                "try increasing system "
+                                "fs.aio-max-nr to 1048576 or larger or "
+                                "setting innodb_use_native_aio = 0 in my.cnf\n");
+                        srv_use_native_aio = FALSE;
+			goto skip_native_aio;
 		}
 	}
 

storage/xtradb/os/os0file.c

@@ -3463,12 +3463,23 @@ os_aio_array_create(
 		if (!os_aio_linux_create_io_ctx(n/n_segments,
 					   &array->aio_ctx[i])) {
 			/* If something bad happened during aio setup
-			we should call it a day and return right away.
-			We don't care about any leaks because a failure
-			to initialize the io subsystem means that the
-			server (or atleast the innodb storage engine)
-			is not going to startup. */
-			return(NULL);
+			we disable linux native aio.
+                        The disadvantage will be a small memory leak
+                        at shutdown but that's ok compared to a crash
+                        or a not working server.
+                        This frequently happens when running the test suite
+                        with many threads on a system with low fs.aio-max-nr!
+                        */
+
+                        fprintf(stderr,
+                                "  InnoDB: Warning: Linux Native AIO disabled "
+                                "because os_aio_linux_create_io_ctx() "
+                                "failed. To get rid of this warning you can "
+                                "try increasing system "
+                                "fs.aio-max-nr to 1048576 or larger or "
+                                "setting innodb_use_native_aio = 0 in my.cnf\n");
+                        srv_use_native_aio = FALSE;
+			goto skip_native_aio;
 		}
 	}
 

storage/xtradb/srv/srv0start.c

@@ -1509,10 +1509,20 @@ innobase_start_or_create_for_mysql(void)
 	}
 # endif /* __WIN__ */
 
-	os_aio_init(io_limit,
-		    srv_n_read_io_threads,
-		    srv_n_write_io_threads,
-		    SRV_MAX_N_PENDING_SYNC_IOS);
+	if (!os_aio_init(io_limit,
+                         srv_n_read_io_threads,
+                         srv_n_write_io_threads,
+                         SRV_MAX_N_PENDING_SYNC_IOS))
+        {
+		ut_print_timestamp(stderr);
+		fprintf(stderr,
+			" InnoDB: Fatal error: cannot initialize AIO"
+			" sub-system\n");
+#if defined(LINUX_NATIVE_AIO)
+                fprintf(stderr, "You can try increasing system fs.aio-max-nr to 1048576 or larger or setting innodb_use_native_aio = 0 in my.cnf\n");
+#endif
+                return(DB_ERROR);
+        }
 
 	fil_init(srv_file_per_table ? 50000 : 5000,
 		 srv_max_n_open_files);