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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jakub Kicinski <jakub.kicinski@netronome.com>,
	Arjun Roy <arjunroy.kdev@gmail.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org, arjunroy@google.com,
	soheil@google.com, edumazet@google.com
Subject: Re: [PATCH net-next] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE_SIZE.
Date: Sun, 15 Dec 2019 11:59:40 -0800	[thread overview]
Message-ID: <80810ad7-a044-a88f-6032-0508661aadc2@gmail.com> (raw)
In-Reply-To: <20191215112214.3dd72168@cakuba.netronome.com>



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.


      reply	other threads:[~2019-12-15 19:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]

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