From: "Michael S. Tsirkin" <mst@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.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: Mon, 4 Jun 2012 22:48:07 +0300 [thread overview]
Message-ID: <20120604194806.GB1648@redhat.com> (raw)
In-Reply-To: <1338837842.2760.1883.camel@edumazet-glaptop>
On Mon, Jun 04, 2012 at 09:24:02PM +0200, Eric Dumazet wrote:
> On Mon, 2012-06-04 at 21:16 +0300, Michael S. Tsirkin wrote:
>
> > Will take a look, thanks.
> > By the way, this comment at build_skb:
> > * @frag_size: size of fragment, or 0 if head was kmalloced
> >
> > is not very clear to me. Could you clarify what exactly size
> > of fragment means in this context?
> >
>
>
> If your driver did :
>
> data = kmalloc(100) then you use @frag_size=0, so that build_skb() does
> the ksize(data) to fetch real size (It can depend on slab/slub/sob
> allocator)
>
>
> If you used netdev_alloc_frag(128), then you use 128 because there is no
> way build_skb() can guess the size of the fragment. Its also how we
> signal to build_skb() that skb->head_frag is set to 1.
>
> __netdev_alloc_skb() for example does :
>
> void *data = netdev_alloc_frag(fragsz);
> skb = build_skb(data, fragsz);
>
If I do this what will truesize be? 128, no?
next prev parent reply other threads:[~2012-06-04 19:48 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 [this message]
2012-06-04 19:56 ` Eric Dumazet
2012-06-04 21:20 ` Michael S. Tsirkin
2012-06-05 2:50 ` Eric Dumazet
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
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