Poor Performance with Oracle Redo Log I/O using direct aio via io_submit on XFS filesystems.

Issue

• Customers who use file systems for the Oracle Redo Log, and in this specific case XFS have seen performance regressions when moving from 7.2 to 7.8.
• Very slow io_submit syscalls lead to poor Oracle DB performance when the Oracle log writer process uses XFS filesystems, without any visible delays in iostat on the disks used by the filesystem.