RE: skb allocation problems

From: Imran.Patel@nokia.com
Date: Tue Apr 10 2001 - 11:27:29 EST


> On Mon, Apr 09, 2001 at 07:03:46PM +0300, Imran.Patel@nokia.com wrote:
> > I have written a test module which closely mirrors what my
> code tries to
> > do(attached below). This is what i get:
> >
> > PRE_R: old skb:c371ee40 new skb:c371ee30
>
> I guess oldskb->len is <=0xc, and the slab allocator packs
> them near together
> in the same zone.

nope. i have checked it, the length of the older skb is perfectly ok.....and
i even found that this weird behaviour happens only when the old skb buffer
length is between 80 and 224 bytes.

and apart from this problem, i even found out that when i send a packet >=
186 bytes the kernel allocates a lot of memory in the skb...the output from
a simple test module is below:

PRE_R: skb: c7aa0da0 skblen: 185 headroom: 32 tailroom: 7 total_len: 224
PRE_R: skb: c7a43020 skblen: 186 headroom: 32 tailroom: 1334 total_len: 1552

This was generated by sending ipv4 ping packets of different sizes...I
tested it using 2.4.1 and 2.4.3 on two machines (both dual stack).
What the hell's going on :( ???

imran

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This archive was generated by hypermail 2b29 : Sun Apr 15 2001 - 21:00:13 EST