Re: [PATCH] net: allow pskb_expand_head() to get maximum tailroom

David Miller
2012-04-11T14:11:34Z

From: Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Date: Wed, 11 Apr 2012 08:08:39 +0200

> Marc Merlin reported many order-1 allocations failures in TX path on its
> wireless setup, that dont make any sense with MTU=1500 network, and non
> SG capable hardware.
>
> Turns out part of the problem comes from pskb_expand_head() not using
> ksize() to get exact head size given by kmalloc(). Doing the same thing
> than __alloc_skb() allows more tailroom in skb and can prevent future
> reallocations.
>
> As a bonus, struct skb_shared_info becomes cache line aligned.
>
> Reported-by: Marc MERLIN <marc-xnduUnryOU1AfugRpC6u6w@public.gmane.org>
> Tested-by: Marc MERLIN <marc-xnduUnryOU1AfugRpC6u6w@public.gmane.org>
> Signed-off-by: Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied and queued up for -stable.
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