napi_build_skb() reuses per-cpu NAPI skbuff_head cache in order
to save some cycles on freeing/allocating skbuff_heads on every
new Rx or completed Tx.
igb driver runs Tx completion polling cycle right before the Rx
one and uses napi_consume_skb() to feed the cache with skbuff_heads
of completed entries, so it's never empty and always warm at that
moment. Switch to the napi_build_skb() to relax mm pressure on
heavy Rx.
Signed-off-by: NAlexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: NMichal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: NGurucharan G <gurucharanx.g@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>