* [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
@ 2018-12-10 5:06 Prashant Bhole
2018-12-10 9:52 ` Jason Wang
2018-12-10 18:04 ` Michael S. Tsirkin
0 siblings, 2 replies; 3+ messages in thread
From: Prashant Bhole @ 2018-12-10 5:06 UTC (permalink / raw)
To: David S . Miller
Cc: Prashant Bhole, Jason Wang, Michael S . Tsirkin, netdev,
Toshiaki Makita
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_q7@lab.ntt.co.jp>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
2018-12-10 5:06 [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
@ 2018-12-10 9:52 ` Jason Wang
2018-12-10 18:04 ` Michael S. Tsirkin
1 sibling, 0 replies; 3+ messages in thread
From: Jason Wang @ 2018-12-10 9:52 UTC (permalink / raw)
To: Prashant Bhole, David S . Miller
Cc: Michael S . Tsirkin, netdev, Toshiaki Makita
On 2018/12/10 下午1:06, 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_q7@lab.ntt.co.jp>
> ---
> 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);
Acked-by: Jason Wang <jasowang@redhat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
2018-12-10 5:06 [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
2018-12-10 9:52 ` Jason Wang
@ 2018-12-10 18:04 ` Michael S. Tsirkin
1 sibling, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2018-12-10 18:04 UTC (permalink / raw)
To: Prashant Bhole; +Cc: David S . Miller, Jason Wang, netdev, Toshiaki Makita
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_q7@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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-12-10 18:04 UTC | newest]
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2018-12-10 5:06 [PATCH net-next] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
2018-12-10 9:52 ` Jason Wang
2018-12-10 18:04 ` Michael S. Tsirkin
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