From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] net: Frag list lost on head expansion.
Date: Fri, 03 Sep 2010 08:19:28 +0200 [thread overview]
Message-ID: <1283494768.3699.1507.camel@edumazet-laptop> (raw)
In-Reply-To: <1283492880.3699.1437.camel@edumazet-laptop>
Le vendredi 03 septembre 2010 à 07:48 +0200, Eric Dumazet a écrit :
> David, I had this same idea some days ago when reviewing this code,
> but when I came to conclusion we could not avoid the get_page /
> put_page() on skb_shinfo(skb)->frags[i].page. I thought it was not worth
> trying to avoid the frag_list grab/release operation.
>
> But we are the only user of this skb and skb_shinfo(skb)->frag_list, so
> your patch seems good to me.
>
> Please note you are not fixing a bug, because the new frag_list pointer
> was correctly copied in the
>
> memcpy(data + size, skb_end_pointer(skb),
> offsetof(struct skb_shared_info,
> frags[skb_shinfo(skb)->nr_frags]));
>
> Please rewrite the changelog to say this patch is an optimization, to
> avoid the atomic ops on each skb found in frag_list ?
>
Well, skb is not shared, but we have no guarantee skb_shinfo(skb) is
not.
To optimize this thing, you'll need to add a new parameter to
skb_release_data() ?
next prev parent reply other threads:[~2010-09-03 6:19 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-03 3:43 [PATCH] net: Frag list lost on head expansion David Miller
2010-09-03 5:48 ` Eric Dumazet
2010-09-03 6:19 ` Eric Dumazet [this message]
2010-09-03 9:09 ` [PATCH net-next-2.6] net: pskb_expand_head() optimization Eric Dumazet
2010-09-03 13:46 ` David Miller
2010-09-07 2:20 ` David Miller
2010-09-07 5:02 ` Eric Dumazet
2010-09-07 5:05 ` David Miller
2010-09-07 9:16 ` Jarek Poplawski
2010-09-07 9:37 ` Eric Dumazet
2010-09-10 19:54 ` David Miller
2010-09-11 12:31 ` Jarek Poplawski
2010-09-12 3:30 ` David Miller
2010-09-12 10:45 ` Jarek Poplawski
2010-09-12 10:58 ` Jarek Poplawski
2010-09-12 15:58 ` David Miller
2010-09-12 16:13 ` David Miller
2010-09-12 20:57 ` Jarek Poplawski
2010-09-12 22:08 ` David Miller
2010-09-13 7:49 ` Jarek Poplawski
2010-09-12 19:55 ` Ben Pfaff
2010-09-12 20:24 ` David Miller
2010-09-12 20:45 ` Jarek Poplawski
2010-09-20 0:17 ` David Miller
2010-09-20 7:21 ` Jarek Poplawski
2010-09-20 9:02 ` Eric Dumazet
2010-09-20 9:14 ` Jarek Poplawski
2010-09-20 12:12 ` Jarek Poplawski
2010-09-20 12:40 ` Eric Dumazet
2010-09-20 16:59 ` David Miller
2010-09-07 1:25 ` David Miller
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