[PATCH] net: ena: Do not waste napi skb cache

From: Hyeonggon Yoo
Date: Sun Jan 23 2022 - 06:56:36 EST


By profiling, discovered that ena device driver allocates skb by
build_skb() and frees by napi_skb_cache_put(). Because the driver
does not use napi skb cache in allocation path, napi skb cache is
periodically filled and flushed. This is waste of napi skb cache.

As ena_alloc_skb() is called only in napi, Use napi_build_skb()
instead of build_skb() to when allocating skb.

This patch was tested on aws a1.metal instance.

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
---
drivers/net/ethernet/amazon/ena/ena_netdev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index c72f0c7ff4aa..2c67fb1703c5 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1407,7 +1407,7 @@ static struct sk_buff *ena_alloc_skb(struct ena_ring *rx_ring, void *first_frag)
skb = netdev_alloc_skb_ip_align(rx_ring->netdev,
rx_ring->rx_copybreak);
else
- skb = build_skb(first_frag, ENA_PAGE_SIZE);
+ skb = napi_build_skb(first_frag, ENA_PAGE_SIZE);

if (unlikely(!skb)) {
ena_increase_stat(&rx_ring->rx_stats.skb_alloc_fail, 1,
--
2.33.1