On 11/01/2011 01:48 PM, Daniel P. Berrange wrote:
On Tue, Nov 01, 2011 at 01:27:56PM -0500, Anthony Liguori wrote:
On 10/20/2011 10:13 AM, Daniel P. Berrange wrote:
On Fri, Oct 07, 2011 at 04:49:13PM +0530, Aneesh Kumar K.V wrote:
On Fri, 7 Oct 2011 10:27:56 +0100, "Daniel P. Berrange"<berra...@redhat.com>
wrote:
On Thu, Sep 29, 2011 at 04:22:16PM +0100, Daniel P. Berrange wrote:
I've done some tests with ever larger mount tags, and managed to increase
the MAX_TAG_LEN value to 1023 before I started getting guest failures.
So if the config space is really 1023 bytes in size, it doesn't seem too
unrealistic to allow 255 bytes of it for the mount_tag, or at the very
least increase it from 32 to 128 ?
Last time we discussed this Anthony wanted to keep the config space
usage minimal, hence we agreed on the size 32 bytes.
Ping ? Anyone ....
Does anyone have any clear information about the per-device config
space we have available ? As above I'd really like us to raise
the mount_tag length even just a little bit higher for QEMU 1.0,
if we have the PCI config space available to play with.
Yes, PCI PIO space is very small. I think 128 is even pushing it.
Odd, because I managed to pass through a 1023 byte path without
appearing to have any trouble. Is the space per-device, or global
to all devices. If the latter, I could understand the desire to
keep it smaller.
It's global so it ends up being a problem when you have many devices.
Why not add a feature that exchanges the tag through another
mechanism such that there doesn't need to be a limit? It could be
as simple as adding an fsstat .L operation or something like that.
That would require kernel side updates too I presume, so if that
kind of change is the only option, I think I'll just have to change
my app's code to cope with the current smaller limits for now.
Right.
Regards,
Anthony Liguori
Regards,
Daniel
