On Wed, Mar 12, 2014 at 07:10:42PM +0100, Paolo Bonzini wrote: > 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. Yup, it was completely a bug at my end. Now that is fixed, fstrim works perfectly. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming blog: http://rwmj.wordpress.com Fedora now supports 80 OCaml packages (the OPEN alternative to F#) -- 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
