From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Neal Cardwell <ncardwell@google.com>,
Yuchung Cheng <ycheng@google.com>
Subject: Re: [PATCH net-next] tcp: add tcp_add_backlog()
Date: Mon, 29 Aug 2016 16:33:28 -0300 [thread overview]
Message-ID: <20160829193328.GD11144@localhost.localdomain> (raw)
In-Reply-To: <1472498557.14381.275.camel@edumazet-glaptop3.roam.corp.google.com>
On Mon, Aug 29, 2016 at 12:22:37PM -0700, Eric Dumazet wrote:
> On Mon, 2016-08-29 at 15:51 -0300, Marcelo Ricardo Leitner wrote:
> > skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
> >
> > Shouldn't __pskb_pull_tail() already fix this? As it seems the expected
> > behavior and it would have a more global effect then. For drivers not
> > using copybreak, that's needed here anyway, but maybe this help other
> > protocols/situations too.
>
> That would be difficult, because some callers do their own truesize
> tacking (skb might be attached/charged to a socket, so changing
> skb->truesize would need to adjust the amount that was charged)
>
> This is why pskb_expand_head() is not allowed to mess with skb->truesize
> (but in the opposite way, since we probably are increasing
> skb->truesize)
>
Ok, makes sense.
> Not sure it is worth the pain in fast path, where packets are consumed
> so fast that their skb->truesize being slightly over estimated is not an
> issue.
Good point, thanks.
next prev parent reply other threads:[~2016-08-29 19:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-27 14:37 [PATCH net-next] tcp: add tcp_add_backlog() Eric Dumazet
2016-08-27 16:13 ` Yuchung Cheng
2016-08-27 16:25 ` Eric Dumazet
2016-08-29 16:53 ` Yuchung Cheng
2016-08-27 18:24 ` Neal Cardwell
2016-08-29 4:20 ` David Miller
2016-08-29 18:51 ` Marcelo Ricardo Leitner
2016-08-29 19:22 ` Eric Dumazet
2016-08-29 19:33 ` Marcelo Ricardo Leitner [this message]
2016-09-22 22:34 ` Marcelo Ricardo Leitner
2016-09-22 23:21 ` Eric Dumazet
2016-09-23 12:45 ` Marcelo Ricardo Leitner
2016-09-23 13:42 ` Eric Dumazet
2016-09-23 14:09 ` Marcelo Ricardo Leitner
2016-09-23 14:36 ` Eric Dumazet
2016-09-23 14:43 ` David Laight
2016-09-23 15:12 ` Marcelo Ricardo Leitner
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