On Mon, Dec 10, 2018 at 02:06:18PM +0900, Prashant Bhole wrote: > tun_xdp_one() runs with local bh disabled. So there is no need to > disable preemption by calling get_cpu_ptr while updating stats. This > patch replaces the use of get_cpu_ptr() with this_cpu_ptr() as a > micro-optimization. Also removes related put_cpu_ptr call. > > Signed-off-by: Prashant Bhole <bhole_prashant...@lab.ntt.co.jp>
Seems to make sense but how about a comment here explaining by it's safe? > --- > drivers/net/tun.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 6760b86547df..abb750a9c9ca 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -2494,12 +2494,11 @@ static int tun_xdp_one(struct tun_struct *tun, > skb_record_rx_queue(skb, tfile->queue_index); > netif_receive_skb(skb); > > - stats = get_cpu_ptr(tun->pcpu_stats); > + stats = this_cpu_ptr(tun->pcpu_stats); > u64_stats_update_begin(&stats->syncp); > stats->rx_packets++; > stats->rx_bytes += skb->len; > u64_stats_update_end(&stats->syncp); > - put_cpu_ptr(stats); > > if (rxhash) > tun_flow_update(tun, rxhash, tfile); > -- > 2.17.2 >
