netkvm: enhancing host throughput by combining virtio header and data in a single descriptor, where possible

[zjmletang]

… in a single memory block

for the problem description
please visit #1078

Signed-off-by: Zhang JianMing [email protected]

[JonKohler]

cc @sb-ntnx

[jumbi77]

What the status of this PR?

[YanVugenfirer]

@zjmletang Do you want to rebase and fix the CI issues?

[zjmletang]

@zjmletang Do you want to rebase and fix the CI issues?

@YanVugenfirer Yes, I would like to rebase and fix the CI issues. However, I am currently away and may need a few more days to address this. Thank you for your understanding!

[YanVugenfirer]

@zjmletang No problem.

[zjmletang]

@YanVugenfirer @ybendito
hi,I've taken some time to revisit this patch and have some concerns regarding its compatibility with the latest design principles in the master branch. Specifically, I see potential conflicts that I’d like to discuss regarding whether this patch can be merged.

To recap, this patch was originally submitted to facilitate discussion around the issue, and the consensus at that time was that the changes were too sensitive to be integrated into the upstream community for now.

Here are the specific points of conflict I’ve identified with the latest master:

The commit ec9e1f5
appears to focus on memory efficiency by employing a header block layout: virtio header + indirect area + tail . My patch, however, would disrupt this layout. I propose a structure that combines the virtio header and data, aiming to represent them with a single descriptor, while either allocating the indirect area separately or placing it at the end of the combined virtio header and data.. The goal of my change is to utilize a single descriptor to represent a receive buffer, which could reduce DMA requests on the host side (as detailed in the related issue).
I’m not sure if the community is open to considering this kind of change. I would appreciate your insights on whether this direction could be acceptable.

[JonKohler]

If we can do it in a way that doesn't make things unstable, I would absolutely be open to this. Sounds like a great idea