MDEV-10918 Innodb/Linux - Fallback to simulated aio if io_setup() fails, e.g due to insufficient resources

Author: vaintroub

mysql-test/mysql-test-run.pl

@@ -4396,9 +4396,8 @@ ($$)
      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|,
+     qr|InnoDB: io_setup\(\) attempt|,
+     qr|InnoDB: io_setup\(\) failed with EAGAIN|,
      qr|setrlimit could not change the size of core files to 'infinity';|,
      qr|feedback plugin: failed to retrieve the MAC address|,
      qr|Plugin 'FEEDBACK' init function returned error|,

storage/innobase/os/os0file.cc

@@ -6560,12 +6560,25 @@ AIO::init_linux_native_aio()
 
 		if (!linux_create_io_ctx(max_events, ctx)) {
 			/* 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(DB_IO_ERROR);
+			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!
+			*/
+
+			ib::warn()
+				<< "Warning: Linux Native AIO disabled "
+				<< "because _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";
+			ut_free(m_aio_ctx);
+			m_aio_ctx = 0;
+			srv_use_native_aio = FALSE;
+			return(DB_SUCCESS);
 		}
 	}