Il 12/03/2014 11:17, Richard W.M. Jones ha scritto:
Somewhere, the discard requests are disappearing in the stack (or more likely, being delayed). blktrace/trace-cmd somehow forces them out. But fsync/sync/umount/sleep does not. They might be stuck in qemu too ...
No, this I can be quite sure about. QEMU sends them as soon as they are received in the SCSI layer. If they were ill-formed, QEMU would fail them. If they got stuck, sooner or later you'd not be able to do I/O anymore (there is a queue depth limit) and the guest would start getting timeouts.
Also, certainly blktrace would have no effect on QEMU. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
