netdev - Re: [PATCH net-next v2] tcp: Set rcv zerocopy hint correctly if skb last frag is < PAGE

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Message-ID: <20191215121510.25ad4353@cakuba.netronome.com>
Date:   Sun, 15 Dec 2019 12:15:10 -0800
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Arjun Roy <arjunroy@...gle.com>,
        Soheil Hassas Yeganeh <soheil@...gle.com>
Subject: Re: [PATCH net-next v2] tcp: Set rcv zerocopy hint correctly if skb
 last frag is < PAGE_SIZE

On Sun, 15 Dec 2019 11:54:51 -0800, Eric Dumazet wrote:
> From: Arjun Roy <arjunroy@...gle.com>
> 
> 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.
> 
> recv_skip_hint is used by the application to skip over
> bytes that can not be mmaped, so returning a too big
> chunk is pessimistic and forces more bytes to be copied.
> 
> Signed-off-by: Arjun Roy <arjunroy@...gle.com>
> Acked-by: Soheil Hassas Yeganeh <soheil@...gle.com>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Applied, thank you!!