Re: [Qemu-devel] [RFC] Disk integrity in QEMU

[Ian Jackson]

Anthony Liguori writes ("Re: [Qemu-devel] [RFC] Disk integrity in QEMU"):
> Do you mean that the guest can control host disk cachability?

Yes.

>  We've switched to always use O_DSYNC by default.  There was a very
> long thread about it including benchmarks.  With the right posix-aio
> tuning, we can use O_DSYNC without hurting performance*.

Right.

With the change in my tree, the guest can turn on the use of the
host's buffer cache for writes (ie, turn off the use of O_DSYNC),
using the appropriate cache control features in the IDE controller
(and have write barriers with the FLUSH CACHE command).

But this patch will need to be reworked into a coherent state for
resubmission because of the upstream changes you mention.

Ian.