From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>, David Miller <davem@davemloft.net>,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] net: netdev_alloc_skb() use build_skb()
Date: Tue, 05 Jun 2012 04:50:31 +0200 [thread overview]
Message-ID: <1338864631.2760.1971.camel@edumazet-glaptop> (raw)
In-Reply-To: <20120604212050.GA2139@redhat.com>
On Tue, 2012-06-05 at 00:20 +0300, Michael S. Tsirkin wrote:
> On Mon, Jun 04, 2012 at 09:56:52PM +0200, Eric Dumazet wrote:
> > On Mon, 2012-06-04 at 22:48 +0300, Michael S. Tsirkin wrote:
> >
> > > If I do this what will truesize be? 128, no?
> >
> > My example was not correct, since you must have enough room for the
> > SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) ( 320 bytes )
> >
> > So it would be 128 + 320 = 448
> >
>
>
> Ugh. I forgot about that. shinfo goes into the same page,
> so we'll have to also make all frags shorter by 320
> to leave space for shinfo at tail.
> overall looks like we need hyprevisor extensions if
> we want to use build_skb ...
Maybe not.
If you provided a 2048 bytes block and hypervisor filled one (small)
frame, there might be available room at the end of the block for the
shinfo already.
If yes : You can use build_skb()
If not : netdev_alloc_skb_ip_align()
I mentioned this trick for ixgbe driver.
next prev parent reply other threads:[~2012-06-05 2:50 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-17 12:18 Stable regression with 'tcp: allow splice() to build full TSO packets' Willy Tarreau
2012-05-17 15:01 ` Willy Tarreau
2012-05-17 15:43 ` Eric Dumazet
2012-05-17 15:56 ` Willy Tarreau
2012-05-17 16:33 ` Eric Dumazet
2012-05-17 16:40 ` Willy Tarreau
2012-05-17 16:47 ` Eric Dumazet
2012-05-17 16:49 ` Eric Dumazet
2012-05-17 17:22 ` Willy Tarreau
2012-05-17 17:34 ` [PATCH net-next] net: netdev_alloc_skb() use build_skb() Eric Dumazet
2012-05-17 17:45 ` Willy Tarreau
2012-06-04 12:39 ` Michael S. Tsirkin
2012-06-04 12:44 ` Willy Tarreau
2012-05-17 19:53 ` David Miller
2012-05-18 4:41 ` Eric Dumazet
2012-06-04 12:37 ` Michael S. Tsirkin
2012-06-04 13:06 ` Eric Dumazet
2012-06-04 13:41 ` Michael S. Tsirkin
2012-06-04 14:01 ` Eric Dumazet
2012-06-04 14:09 ` Eric Dumazet
2012-06-04 14:17 ` Michael S. Tsirkin
2012-06-04 15:01 ` Eric Dumazet
2012-06-04 17:20 ` Michael S. Tsirkin
2012-06-04 17:44 ` Eric Dumazet
2012-06-04 18:16 ` Michael S. Tsirkin
2012-06-04 19:24 ` Eric Dumazet
2012-06-04 19:48 ` Michael S. Tsirkin
2012-06-04 19:56 ` Eric Dumazet
2012-06-04 21:20 ` Michael S. Tsirkin
2012-06-05 2:50 ` Eric Dumazet [this message]
2012-06-04 18:16 ` Michael S. Tsirkin
2012-06-04 19:29 ` Eric Dumazet
2012-06-04 19:43 ` Michael S. Tsirkin
2012-06-04 19:52 ` Eric Dumazet
2012-06-04 21:54 ` Michael S. Tsirkin
2012-06-05 2:46 ` Eric Dumazet
2012-06-04 19:56 ` Michael S. Tsirkin
2012-06-04 20:05 ` Eric Dumazet
2012-05-17 18:38 ` Stable regression with 'tcp: allow splice() to build full TSO packets' Ben Hutchings
2012-05-17 19:55 ` David Miller
2012-05-17 20:04 ` Willy Tarreau
2012-05-17 20:07 ` David Miller
2012-05-17 20:41 ` Eric Dumazet
2012-05-17 21:14 ` Willy Tarreau
2012-05-17 21:40 ` Eric Dumazet
2012-05-17 21:50 ` Eric Dumazet
2012-05-17 21:57 ` Willy Tarreau
2012-05-17 22:01 ` Eric Dumazet
2012-05-17 22:10 ` Eric Dumazet
2012-05-17 22:16 ` Willy Tarreau
2012-05-17 22:22 ` Eric Dumazet
2012-05-17 22:24 ` Willy Tarreau
2012-05-17 22:25 ` David Miller
2012-05-17 22:30 ` Willy Tarreau
2012-05-17 22:35 ` David Miller
2012-05-17 22:49 ` Willy Tarreau
2012-05-17 22:27 ` Joe Perches
2012-05-17 21:54 ` Willy Tarreau
2012-05-17 21:47 ` Willy Tarreau
2012-05-17 22:14 ` Eric Dumazet
2012-05-17 22:29 ` Willy Tarreau
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1338864631.2760.1971.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=davem@davemloft.net \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=w@1wt.eu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).