On 11/13/2013 07:11 AM, Jesse Gross wrote:
On Mon, Nov 11, 2013 at 11:53 PM, Thomas Graf <[email protected]> wrote:
On 11/11/2013 04:50 PM, Ben Pfaff wrote:
On Mon, Nov 11, 2013 at 04:36:24PM +0100, Thomas Graf wrote:
Following commit (''netlink: Do not enforce alignment of last Netlink
attribute''), signal the ability to receive unaligned Netlink messages
to the datapath to enable utilization of zerocopy optimizations.
Signed-off-by: Thomas Graf <[email protected]>
Seems OK from a userspace point of view. I am a little concerned that
downgrading userspace without deleting and re-creating the datapath
(e.g. via "force-reload-kmod") will result in a totally broken setup
since userspace will then drop every packet from the kernel.
Is that something that occurs occasionally in installations? Utilizing
the version field in the genl header could be used to track this and
clear user_features.
It's probably a good idea. I could see us having more of these
features flags in the future (although obviously we should try to
avoid them if possible) and, as Ben said, it would potentially lead to
a bad state otherwise.
I'm not sure exactly what you have in mind though, can you elaborate a little?
My initial thought was to use a version field to notice the replacement
of user space. On second thought that is not required, modifying user
space to provide the user features in OVS_DP_CMD_GET as well will
overwrite the features. Resetting user_features to 0 if not features are
provided will provide backwards compatibility to versions not aware of
user features yet. Thoughts?
(By the way, it might be a good idea to keep the same CC list on all
of the patches. Otherwise, some people might miss parts of the
discussion.)
I did not CC netdev because this is a pure user space patch and the
respective kernel bits are included in v5 of the kernel series.
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