From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from rhun.apana.org.au ([64.62.148.172]:42739 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751108AbYEDDRE (ORCPT ); Sat, 3 May 2008 23:17:04 -0400 Date: Sun, 4 May 2008 11:16:52 +0800 From: Herbert Xu To: Johannes Berg Cc: David Miller , mb@bu3sch.de, netdev@vger.kernel.org, linux-wireless@vger.kernel.org Subject: Re: mac80211 truesize bugs Message-ID: <20080504031652.GA30993@gondor.apana.org.au> (sfid-20080504_051655_947748_4395920F) References: <1209760731.3608.17.camel@johannes.berg> <20080502.163334.148944203.davem@davemloft.net> <1209815533.3987.21.camel@johannes.berg> <20080503.180300.10562559.davem@davemloft.net> <1209865354.6210.23.camel@johannes.berg> <20080504020203.GA30514@gondor.apana.org.au> <1209866916.6210.39.camel@johannes.berg> <20080504021213.GA30660@gondor.apana.org.au> <1209867740.6210.46.camel@johannes.berg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1209867740.6210.46.camel@johannes.berg> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, May 04, 2008 at 04:22:20AM +0200, Johannes Berg wrote: > > Yes, wireless always needs at least 24 bytes, but more likely 34 > (encryption+QoS). However, I just increased LL_MAX_HEADER to 54 and that > doesn't seem to have helped. How did you test it? > What's wrong with, instead, doing skb_orphan() and then > pskb_expand_head()? That seems to have the same effect. If you packet sticks around for long enough then this skews the accounting. In any case, thinking too much about optimising this part is a waste of time because we should be thinking about having enough head room in the packet so that we don't have to expand it in the first place except for the odd packet. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt