* [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE.
@ 2019-12-12 22:59 Arjun Roy
2019-12-15 19:22 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: Arjun Roy @ 2019-12-12 22:59 UTC (permalink / raw)
To: davem, netdev; +Cc: arjunroy, soheil, edumazet, Arjun Roy
At present, if the last frag of paged data in a skb has < PAGE_SIZE
data, we compute the recv_skip_hint as being equal to the size of that
frag and the entire next skb.
Instead, just return the runt frag size as the hint.
Signed-off-by: Arjun Roy <arjunroy@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/tcp.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 34490d972758..b9623d896469 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1904,6 +1904,8 @@ static int tcp_zerocopy_receive(struct sock *sk,
while (length + PAGE_SIZE <= zc->length) {
if (zc->recv_skip_hint < PAGE_SIZE) {
if (skb) {
+ if (zc->recv_skip_hint > 0)
+ break;
skb = skb->next;
offset = seq - TCP_SKB_CB(skb)->seq;
} else {
--
2.24.1.735.g03f4e72817-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE.
2019-12-12 22:59 [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE Arjun Roy
@ 2019-12-15 19:22 ` Jakub Kicinski
2019-12-15 19:59 ` Eric Dumazet
0 siblings, 1 reply; 3+ messages in thread
From: Jakub Kicinski @ 2019-12-15 19:22 UTC (permalink / raw)
To: Arjun Roy; +Cc: davem, netdev, arjunroy, soheil, edumazet
On Thu, 12 Dec 2019 14:59:30 -0800, Arjun Roy wrote:
> At present, if the last frag of paged data in a skb has < PAGE_SIZE
> data, we compute the recv_skip_hint as being equal to the size of that
> frag and the entire next skb.
>
> Instead, just return the runt frag size as the hint.
nit: this commit message doesn't really tell us why or what the effects
are going to be.
> Signed-off-by: Arjun Roy <arjunroy@google.com>
> Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
WARNING: Missing Signed-off-by: line by nominal patch author 'Arjun Roy <arjunroy.kdev@gmail.com>'
You gotta send it from the same address you signed it off from.
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 34490d972758..b9623d896469 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -1904,6 +1904,8 @@ static int tcp_zerocopy_receive(struct sock *sk,
> while (length + PAGE_SIZE <= zc->length) {
> if (zc->recv_skip_hint < PAGE_SIZE) {
> if (skb) {
> + if (zc->recv_skip_hint > 0)
> + break;
> skb = skb->next;
> offset = seq - TCP_SKB_CB(skb)->seq;
> } else {
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE.
2019-12-15 19:22 ` Jakub Kicinski
@ 2019-12-15 19:59 ` Eric Dumazet
0 siblings, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2019-12-15 19:59 UTC (permalink / raw)
To: Jakub Kicinski, Arjun Roy; +Cc: davem, netdev, arjunroy, soheil, edumazet
On 12/15/19 11:22 AM, Jakub Kicinski wrote:
> On Thu, 12 Dec 2019 14:59:30 -0800, Arjun Roy wrote:
>> At present, if the last frag of paged data in a skb has < PAGE_SIZE
>> data, we compute the recv_skip_hint as being equal to the size of that
>> frag and the entire next skb.
>>
>> Instead, just return the runt frag size as the hint.
>
> nit: this commit message doesn't really tell us why or what the effects
> are going to be.
Right, I added a bit of explanation.
Basically we would hint the application to copy more bytes than needed.
Since zerocopy is best effort, this can target net-next
>
>> Signed-off-by: Arjun Roy <arjunroy@google.com>
>> Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>
> WARNING: Missing Signed-off-by: line by nominal patch author 'Arjun Roy <arjunroy.kdev@gmail.com>'
>
> You gotta send it from the same address you signed it off from.
I sent a v2 on behalf of Arjun.
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-12-12 22:59 [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE Arjun Roy
2019-12-15 19:22 ` Jakub Kicinski
2019-12-15 19:59 ` Eric Dumazet
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