[PATCH bpf-next v1 1/2] xdp: recycle Page Pool backed skbs built from XDP frames

Alexander Lobakin
2023-03-01T16:04:21Z

__xdp_build_skb_from_frame() state(d):

/* Until page_pool get SKB return path, release DMA here */

Page Pool got skb pages recycling in April 2021, but missed this
function.

xdp_release_frame() is relevant only for Page Pool backed frames and it
detaches the page from the corresponding Pool in order to make it
freeable via page_frag_free(). It can instead just mark the output skb
as eligible for recycling if the frame is backed by a PP. No change for
other memory model types (the same condition check as before).
cpumap redirect and veth on Page Pool drivers now become zero-alloc (or
almost).

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
net/core/xdp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 8c92fc553317..a2237cfca8e9 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -658,8 +658,8 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
* - RX ring dev queue index (skb_record_rx_queue)
*/

- /* Until page_pool get SKB return path, release DMA here */
- xdp_release_frame(xdpf);
+ if (xdpf->mem.type == MEM_TYPE_PAGE_POOL)
+ skb_mark_for_recycle(skb);

/* Allow SKB to reuse area used by xdp_frame */
xdp_scrub_frame(xdpf);
--
2.39.2