From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: [RFC v2] mac80211: assign needed_headroom/tailroom for netdevs Date: Tue, 06 May 2008 13:13:08 +0200 Message-ID: <1210072389.13316.17.camel@johannes.berg> References: <1210029835.8012.30.camel@johannes.berg> <20080505.163916.239187195.davem@davemloft.net> <1210032076.8012.49.camel@johannes.berg> <20080505.170805.127854312.davem@davemloft.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-wLe7HruyrRYfdzCBEHrq" Cc: tomasw-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linville-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org To: David Miller Return-path: In-Reply-To: <20080505.170805.127854312.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org --=-wLe7HruyrRYfdzCBEHrq Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Mon, 2008-05-05 at 17:08 -0700, David Miller wrote: > From: Johannes Berg > Date: Tue, 06 May 2008 02:01:16 +0200 >=20 > > Right. I just checked, and realised I remembered wrongly, wpa_supplican= t > > actually binds the socket to the ethertype it wants so > > dev_queue_xmit_nit() shouldn't be called. I'll have to check why I got > > so many cloned packets, best see if it still happens with the > > header_cloned() change. >=20 > skb_cloned() is fine, that's what every TCP packet is. >=20 > skb_header_cloned() is what we expect to be false >=20 > I look forward to the results of your investigation :-) This is indeed the case. With that patch of yours (plus changes to make it print out things) I occasionally see header-cloned SKBs [1] and due to my spacing patch haven't yet seen one that didn't have enough headroom. So this will optimise TCP a lot. I haven't tried bridging yet as AP mode is rather unstable at the moment. johannes [1] those coming from ipv6, udp (possibly zeroconf stuff): [34805.481404] MAC80211: got header cloned skb [34805.481422] [] __copy_skb_header+0x1bc/0x20c [34805.481449] [] __skb_clone+0x2c/0xf4 [34805.481459] [] dev_hard_start_xmit+0xf0/0x2f0 [34805.481473] [] __qdisc_run+0x248/0x27c [34805.481488] [] dev_queue_xmit+0x300/0x3cc [34805.481498] [] ip6_output_finish+0xac/0x12c [34805.481515] [] ip6_output+0x56c/0xe64 [34805.481524] [] ip6_local_out+0x34/0x48 [34805.481533] [] ip6_push_pending_frames+0x3c4/0x524 [34805.481542] [] udp_v6_push_pending_frames+0x1e0/0x340 [34805.481559] [] udpv6_sendmsg+0x744/0xa24 [34805.481569] [] inet_sendmsg+0x4c/0x78 [34805.481580] [] sock_sendmsg+0xac/0xe4 [34805.481589] [] sys_sendmsg+0x1e4/0x2a0 [34805.481599] [] sys_socketcall+0xcc/0x1dc [34805.481608] [] ret_from_syscall+0x0/0x38 [34789.711392] MAC80211: got header cloned skb [34789.711411] [] __copy_skb_header+0x1bc/0x20c [34789.711438] [] __skb_clone+0x2c/0xf4 [34789.711448] [] dev_hard_start_xmit+0xf0/0x2f0 [34789.711462] [] __qdisc_run+0x248/0x27c [34789.711478] [] dev_queue_xmit+0x300/0x3cc [34789.711487] [] ip_finish_output+0x1e8/0x354 [34789.711504] [] ip_local_out+0x34/0x48 [34789.711514] [] ip_push_pending_frames+0x2a4/0x3d8 [34789.711525] [] udp_push_pending_frames+0x128/0x39c [34789.711543] [] udp_sendmsg+0x348/0x660 [34789.711553] [] inet_sendmsg+0x4c/0x78 [34789.711564] [] sock_sendmsg+0xac/0xe4 [34789.711574] [] sys_sendmsg+0x1e4/0x2a0 [34789.711583] [] sys_socketcall+0xcc/0x1dc [34789.711593] [] ret_from_syscall+0x0/0x38 --=-wLe7HruyrRYfdzCBEHrq Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iQIVAwUASCA9Q6Vg1VMiehFYAQKj8xAAjgpxCnLpbiHxkFLB7zzU03p/IMc/YRiv i9G+rmqJXnnpLG3khMzaKyiA10+BQwdXjDfwtBS/5wIeOmnvmEr/A074wXiFOjc9 MN+Oz99tM7nYjMDpBsNowrhQg+pvFWAS2y59uGdU9tU/K029Nk11kxybFsgbaUf+ acGMc3dYmJQrkMgy0vbzC4HUB25DBrUxheT8rPZSsp2bL2JNklG1beqt/b0tFscO OzNxVH4YpXcDiqDk9tVFk20/ZNidRa2eCXP7x+lcQnn9HBc7tm+Fnn9zpg0u7WnR g2WsCpK59Qz3jVDTgAb+I8DwSYsiz/s2437YgHRKTkBCjhWTz7MIuzhBNCQzkzK7 glQd1R9B15I7QgeKasSnYCaiW9N/nPXDXYG0BjMfMic9g0VnFW/XIbRO/AqTz6qb xeErW2xXSETcqxFUirBLtq7r/+70JUVb9l0x9gwx6EtFv1ipCKirN57mDQKaBtUA w2U+TqjWtLHA2TVljYzb5HJT1vjNKk6nuT/zm3CT/WrrawPAiVPjnVDC81aUeMdh MvpLQhEIMz8wjKFH9OVBUNymNxx4NS+FIz/Yeqsxyw2qYqWQjrFyW/cft80YPCwj W4S4tIQAdjDxPTnNQYY+2ieWRAvT8Du7p8oSVRJNy6p1SFzFiPsSHZx54ZF7x0sG G0NmnhEewAc= =T4e6 -----END PGP SIGNATURE----- --=-wLe7HruyrRYfdzCBEHrq-- -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html