[net-next,v8,0/4] skbuff: Optimize SKB coalescing for page pool

Message

Liang Chen Dec. 11, 2023, 3:52 a.m. UTC

The combination of the following condition was excluded from skb coalescing:

from->pp_recycle = 1
from->cloned = 1
to->pp_recycle = 1

With page pool in use, this combination can be quite common(ex.
NetworkMananger may lead to the additional packet_type being registered,
thus the cloning). In scenarios with a higher number of small packets, it
can significantly affect the success rate of coalescing.

This patchset aims to optimize this scenario and enable coalescing of this
particular combination. That also involves supporting multiple users
referencing the same fragment of a pp page to accomondate the need to
increment the "from" SKB page's pp page reference count.

Changes from v7:
- move informative documentation for page_pool_fragment_page

Liang Chen (4):
  page_pool: transition to reference count management after page
    draining
  page_pool: halve BIAS_MAX for multiple user references of a fragment
  skbuff: Add a function to check if a page belongs to page_pool
  skbuff: Optimization of SKB coalescing for page pool

 .../net/ethernet/mellanox/mlx5/core/en_rx.c   |  4 +-
 include/linux/mm_types.h                      |  2 +-
 include/net/page_pool/helpers.h               | 65 +++++++++++--------
 include/net/page_pool/types.h                 |  6 +-
 net/core/page_pool.c                          | 14 ++--
 net/core/skbuff.c                             | 48 ++++++++++----
 6 files changed, 87 insertions(+), 52 deletions(-)