[ovs-dev] [PATCHv3] datapath: Cache netlink flow key, mask on flow_put.

Joe Stringer joestringer at nicira.com
Sun Jul 20 22:28:21 UTC 2014


On 19 July 2014 06:13, Jesse Gross <jesse at nicira.com> wrote:

> It's true, the field ordering is not significant if you understand all
> of the fields. The concern is that userspace may want to keep track of
> flows even if it doesn't understand all of the fields (for example, it
> can determine that the kernel provides information about some
> additional fields that userspace doesn't care about and just mask
> those out). In this case, to keep track of what is in the kernel,
> userspace would likely do a hash and comparison over the byte stream
> of the key. In that situation, even if reordering wouldn't cause the
> meaning to change, it would cause the comparison to fail.
>

I see, thanks for explaining. In that case, I'll look at preparing a patch
that does the caching upon the first flow dump.



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