Re: [PATCH net-next V4 0/5] vhost: accelerate metadata access through vmap()

[David Miller]

From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Wed, 23 Jan 2019 17:55:52 +0800

> This series tries to access virtqueue metadata through kernel virtual
> address instead of copy_user() friends since they had too much
> overheads like checks, spec barriers or even hardware feature
> toggling.
> 
> Test shows about 24% improvement on TX PPS. It should benefit other
> cases as well.

I've read over the discussion of patch #5 a few times.

And it seems to me that, at a minimum, a few things still need to
be resolved:

1) More perf data added to commit message.

2) Whether invalidate_range_start() and invalidate_range_end() must
   be paired.

Etc.  So I am marking this series "Changes Requested".