On Fri, 14 Jul 2023 15:13:15 +0200 Jesper Dangaard Brouer wrote:

quoted

Thank Jakub and Jesper for the reviews.
I'm aware of the page_pool.rst doc, and actually tried it before this
patch, but I got lower perf. If I understand correctly, we should call
page_pool_release_page() before passing the SKB to napi_gro_receive().

I found the page_pool_dev_alloc_pages() goes through the slow path,
because the page_pool_release_page() let the page leave the pool.

Do we have to call page_pool_release_page() before passing the SKB
to napi_gro_receive()? Any better way to recycle the pages from the
upper layer of non-XDP case?
  

Today SKB "upper layers" can recycle page_pool backed packet data/page.

Just use skb_mark_for_recycle(skb), then you don't need 
page_pool_release_page().

I guess, we should update the documentation, mentioning this.

Ah, I should probably send in the few cleanups form the huge page
series. It looks like all users of page_pool_release_page() can
be converted to skb recycling, so we should hide it and remove 
from docs?