* [PATCH net-next v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
@ 2018-12-11 2:43 Prashant Bhole
2018-12-11 3:31 ` Michael S. Tsirkin
2018-12-14 21:33 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Prashant Bhole @ 2018-12-11 2:43 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.
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
---
v1 -> v2: Added comment to explain why this change is safe
drivers/net/tun.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 6760b86547df..cb90859d0433 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2494,12 +2494,14 @@ 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);
+ /* No need for get_cpu_ptr() here since this function is
+ * always called with bh disabled
+ */
+ 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 v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
2018-12-11 2:43 [PATCH net-next v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
@ 2018-12-11 3:31 ` Michael S. Tsirkin
2018-12-14 21:33 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2018-12-11 3:31 UTC (permalink / raw)
To: Prashant Bhole; +Cc: David S . Miller, Jason Wang, netdev, Toshiaki Makita
On Tue, Dec 11, 2018 at 11:43:07AM +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.
>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> v1 -> v2: Added comment to explain why this change is safe
>
> drivers/net/tun.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 6760b86547df..cb90859d0433 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -2494,12 +2494,14 @@ 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);
> + /* No need for get_cpu_ptr() here since this function is
> + * always called with bh disabled
> + */
> + 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
* Re: [PATCH net-next v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled
2018-12-11 2:43 [PATCH net-next v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
2018-12-11 3:31 ` Michael S. Tsirkin
@ 2018-12-14 21:33 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2018-12-14 21:33 UTC (permalink / raw)
To: bhole_prashant_q7; +Cc: jasowang, mst, netdev, makita.toshiaki
From: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Date: Tue, 11 Dec 2018 11:43:07 +0900
> 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.
>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
> ---
> v1 -> v2: Added comment to explain why this change is safe
Applied, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-12-14 21:33 UTC | newest]
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2018-12-11 2:43 [PATCH net-next v2] tun: replace get_cpu_ptr with this_cpu_ptr when bh disabled Prashant Bhole
2018-12-11 3:31 ` Michael S. Tsirkin
2018-12-14 21:33 ` David Miller
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