Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752900AbbBALVD (ORCPT ); Sun, 1 Feb 2015 06:21:03 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:41557 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752605AbbBALU7 (ORCPT ); Sun, 1 Feb 2015 06:20:59 -0500 Message-ID: <1422789633.11044.18.camel@infradead.org> Subject: Re: [PATCH] tun: orphan an skb on tx From: David Woodhouse To: Herbert Xu Cc: Eric Dumazet , "Michael S. Tsirkin" , Jan Kiszka , "David S. Miller" , Paul Moore , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , qemu-devel Date: Sun, 01 Feb 2015 11:20:33 +0000 In-Reply-To: <20100414005822.GD18044@gondor.apana.org.au> References: <20100413145944.GA7716@redhat.com> <4BC48F79.5090409@siemens.com> <1271176838.16881.537.camel@edumazet-laptop> <20100413173919.GC26011@redhat.com> <1271183463.16881.545.camel@edumazet-laptop> <20100414005822.GD18044@gondor.apana.org.au> Content-Type: multipart/signed; micalg="sha-1"; protocol="application/x-pkcs7-signature"; boundary="=-veIGnxzbfFksq7FaRHqw" X-Mailer: Evolution 3.12.10 (3.12.10-1.fc21) Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9979 Lines: 161 --=-veIGnxzbfFksq7FaRHqw Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2010-04-14 at 08:58 +0800, Herbert Xu wrote: > On Tue, Apr 13, 2010 at 08:31:03PM +0200, Eric Dumazet wrote: > > > > Herbert Acked your patch, so I guess its OK, but I think it can be > > dangerous. >=20 > The tun socket accounting was never designed to stop it from > flooding another tun interface. It's there to stop it from > transmitting above a destination interface TX bandwidth and > cause unnecessary packet drops. It also limits the total amount > of kernel memory that can be pinned down by a single tun interface. >=20 > In this case, all we're doing is shifting the accounting from the > "hardware" queue to the qdisc queue. >=20 > So your ability to flood a tun interface is essentially unchanged. I've just been looking at VPN performance, using netperf to flood an openconnect/ocserv connection over GigE and profiling my VPN client. If I run netperf over the *unencrypted* link, it only sends 1Gb/s of packets =E2=80=94 because the packets are correctly accounted to netperf's = UDP socket until the moment they're actually transmitted on the wire, and the backpressure works correctly. When I run over the VPN, netperf thinks it sent 2=C2=BD times the amount of TX traffic. Packets are being dropped by the tun device before even feeding them up to the VPN client to be sent =E2=80=94 presumably because o= f this skb_orphan() call. (The client itself should do the right thing, and only suck packets out of the tun at the rate it can shove them out *its* UDP socket.) Did we ever look at the alternative solution of taking ownership only after a timeout, or on demand when we need to shut down the device? --=20 dwmw2 --=-veIGnxzbfFksq7FaRHqw Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIISxDCCBjQw ggQcoAMCAQICAR4wDQYJKoZIhvcNAQEFBQAwfTELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxKTAn BgNVBAMTIFN0YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MB4XDTA3MTAyNDIxMDE1NVoX DTE3MTAyNDIxMDE1NVowgYwxCzAJBgNVBAYTAklMMRYwFAYDVQQKEw1TdGFydENvbSBMdGQuMSsw KQYDVQQLEyJTZWN1cmUgRGlnaXRhbCBDZXJ0aWZpY2F0ZSBTaWduaW5nMTgwNgYDVQQDEy9TdGFy dENvbSBDbGFzcyAxIFByaW1hcnkgSW50ZXJtZWRpYXRlIENsaWVudCBDQTCCASIwDQYJKoZIhvcN AQEBBQADggEPADCCAQoCggEBAMcJg8zOLdgasSmkLhOrlr6KMoOMpohBllVHrdRvEg/q6r8jR+EK 75xCGhR8ToREoqe7zM9/UnC6TS2y9UKTpT1v7RSMzR0t6ndl0TWBuUr/UXBhPk+Kmy7bI4yW4urC +y7P3/1/X7U8ocb8VpH/Clt+4iq7nirMcNh6qJR+xjOhV+VHzQMALuGYn5KZmc1NbJQYclsGkDxD z2UbFqE2+6vIZoL+jb9x4Pa5gNf1TwSDkOkikZB1xtB4ZqtXThaABSONdfmv/Z1pua3FYxnCFmdr /+N2JLKutIxMYqQOJebr/f/h5t95m4JgrM3Y/w7YX9d7YAL9jvN4SydHsU6n65cCAwEAAaOCAa0w ggGpMA8GA1UdEwEB/wQFMAMBAf8wDgYDVR0PAQH/BAQDAgEGMB0GA1UdDgQWBBRTcu2SnODaywFc fH6WNU7y1LhRgjAfBgNVHSMEGDAWgBROC+8apEBbpRdphzDKNGhD0EGu8jBmBggrBgEFBQcBAQRa MFgwJwYIKwYBBQUHMAGGG2h0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9jYTAtBggrBgEFBQcwAoYh aHR0cDovL3d3dy5zdGFydHNzbC5jb20vc2ZzY2EuY3J0MFsGA1UdHwRUMFIwJ6AloCOGIWh0dHA6 Ly93d3cuc3RhcnRzc2wuY29tL3Nmc2NhLmNybDAnoCWgI4YhaHR0cDovL2NybC5zdGFydHNzbC5j b20vc2ZzY2EuY3JsMIGABgNVHSAEeTB3MHUGCysGAQQBgbU3AQIBMGYwLgYIKwYBBQUHAgEWImh0 dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwNAYIKwYBBQUHAgEWKGh0dHA6Ly93d3cu c3RhcnRzc2wuY29tL2ludGVybWVkaWF0ZS5wZGYwDQYJKoZIhvcNAQEFBQADggIBAAqDCH14qywG XLhjjF6uHLkjd02hcdh9hrw+VUsv+q1eeQWB21jWj3kJ96AUlPCoEGZ/ynJNScWy6QMVQjbbMXlt UfO4n4bGGdKo3awPWp61tjAFgraLJgDk+DsSvUD6EowjMTNx25GQgyYJ5RPIzKKR9tQW8gGK+2+R HxkUCTbYFnL6kl8Ch507rUdPPipJ9CgJFws3kDS3gOS5WFMxcjO5DwKfKSETEPrHh7p5shuuNktv sv6hxHTLhiMKX893gxdT3XLS9OKmCv87vkINQcNEcIIoFWbP9HORz9v3vQwR4e3ksLc2JZOAFK+s sS5XMEoznzpihEP0PLc4dCBYjbvSD7kxgDwZ+Aj8Q9PkbvE9sIPP7ON0fz095HdThKjiVJe6vofq +n6b1NBc8XdrQvBmunwxD5nvtTW4vtN6VY7mUCmxsCieuoBJ9OlqmsVWQvifIYf40dJPZkk9YgGT zWLpXDSfLSplbY2LL9C9U0ptvjcDjefLTvqSFc7tw1sEhF0n/qpA2r0GpvkLRDmcSwVyPvmjFBGq Up/pNy8ZuPGQmHwFi2/14+xeSUDG2bwnsYJQG2EdJCB6luQ57GEnTA/yKZSTKI8dDQa8Sd3zfXb1 9mOgSF0bBdXbuKhEpuP9wirslFe6fQ1t5j5R0xi72MZ8ikMu1RQZKCyDbMwazlHiMIIGQjCCBSqg AwIBAgIDCdkyMA0GCSqGSIb3DQEBBQUAMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRD b20gTHRkLjErMCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYG A1UEAxMvU3RhcnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0EwHhcN MTQwNTA0MTczMDIyWhcNMTUwNTA0MjM0MTAxWjBdMRkwFwYDVQQNExAzODNCMTVkSHFQSUR0cDZO MRwwGgYDVQQDDBNkd213MkBpbmZyYWRlYWQub3JnMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZy YWRlYWQub3JnMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAy7K+t+REIdZGFUfgR8Io QrJ/VLZil9I00JcwqTo8BiGy1dqSIB2y923siya5SDKMh1YurtCPsX96cNzwPmmN2cs0MKeVPQWz iQhHk3uKcB6LvvS7pzTahRWMRmTyW3CH+RphRM9plvyClY23GEeEnpBnGz4GaJJiPcJjGgzyZ/tI q473pOlSrDPZnZk43vt/5CJN46nIZOZ2I+PzlgINI+EbiwsXVn3VohHB7nVTwGaRLk5oywGt8ZT7 tDdxn3BQ3inO1sr5MtkV1o2cHlenIC8mlU8nL/mrqqVve7Vib1YQUycW+Pj4CBYm4FTeuctAvNzK U/daeBclOZ8ofgQe2wIDAQABo4IC2TCCAtUwCQYDVR0TBAIwADALBgNVHQ8EBAMCBLAwHQYDVR0l BBYwFAYIKwYBBQUHAwIGCCsGAQUFBwMEMB0GA1UdDgQWBBRAjCSCV70BpLBeXge5DXi+mPhHTTAf BgNVHSMEGDAWgBRTcu2SnODaywFcfH6WNU7y1LhRgjAeBgNVHREEFzAVgRNkd213MkBpbmZyYWRl YWQub3JnMIIBTAYDVR0gBIIBQzCCAT8wggE7BgsrBgEEAYG1NwECAzCCASowLgYIKwYBBQUHAgEW Imh0dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwgfcGCCsGAQUFBwICMIHqMCcWIFN0 YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MAMCAQEagb5UaGlzIGNlcnRpZmljYXRlIHdh cyBpc3N1ZWQgYWNjb3JkaW5nIHRvIHRoZSBDbGFzcyAxIFZhbGlkYXRpb24gcmVxdWlyZW1lbnRz IG9mIHRoZSBTdGFydENvbSBDQSBwb2xpY3ksIHJlbGlhbmNlIG9ubHkgZm9yIHRoZSBpbnRlbmRl ZCBwdXJwb3NlIGluIGNvbXBsaWFuY2Ugb2YgdGhlIHJlbHlpbmcgcGFydHkgb2JsaWdhdGlvbnMu MDYGA1UdHwQvMC0wK6ApoCeGJWh0dHA6Ly9jcmwuc3RhcnRzc2wuY29tL2NydHUxLWNybC5jcmww gY4GCCsGAQUFBwEBBIGBMH8wOQYIKwYBBQUHMAGGLWh0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9z dWIvY2xhc3MxL2NsaWVudC9jYTBCBggrBgEFBQcwAoY2aHR0cDovL2FpYS5zdGFydHNzbC5jb20v Y2VydHMvc3ViLmNsYXNzMS5jbGllbnQuY2EuY3J0MCMGA1UdEgQcMBqGGGh0dHA6Ly93d3cuc3Rh cnRzc2wuY29tLzANBgkqhkiG9w0BAQUFAAOCAQEAWS2KNN7O3vZVtNHXVqgbmijeptKwt+8b6yiF wT3kJoywInPl5U+OeKRZfQKTHghM4Ohof6lF244ZMxhir/xp7l/zkZ/BUbxLwp6kIL27Gi5pgP4D KLnTZheQL9N5Yi/vMONxMWcpcW+ZNv5hnDCfEsfVcLXC8sNLPjx2ezfMIhSSPwBuJpmOun70te4E P0YBqjSalPfvc5fC5KgaYtqTDFwo9Mw25X5HHDC0r6BK5aNrF1nD/xYTX7cdvZZWl7cUApr4PCrn uI2DEn7OWQ/rY407ytV1c5pjvmuv/IT/ZUb/kXV6Q47UvrJp2Ifi2VhsBcnHHasKavjtRCmpDsGM rTCCBkIwggUqoAMCAQICAwnZMjANBgkqhkiG9w0BAQUFADCBjDELMAkGA1UEBhMCSUwxFjAUBgNV BAoTDVN0YXJ0Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNp Z25pbmcxODA2BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xp ZW50IENBMB4XDTE0MDUwNDE3MzAyMloXDTE1MDUwNDIzNDEwMVowXTEZMBcGA1UEDRMQMzgzQjE1 ZEhxUElEdHA2TjEcMBoGA1UEAwwTZHdtdzJAaW5mcmFkZWFkLm9yZzEiMCAGCSqGSIb3DQEJARYT ZHdtdzJAaW5mcmFkZWFkLm9yZzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMuyvrfk RCHWRhVH4EfCKEKyf1S2YpfSNNCXMKk6PAYhstXakiAdsvdt7IsmuUgyjIdWLq7Qj7F/enDc8D5p jdnLNDCnlT0Fs4kIR5N7inAei770u6c02oUVjEZk8ltwh/kaYUTPaZb8gpWNtxhHhJ6QZxs+BmiS Yj3CYxoM8mf7SKuO96TpUqwz2Z2ZON77f+QiTeOpyGTmdiPj85YCDSPhG4sLF1Z91aIRwe51U8Bm kS5OaMsBrfGU+7Q3cZ9wUN4pztbK+TLZFdaNnB5XpyAvJpVPJy/5q6qlb3u1Ym9WEFMnFvj4+AgW JuBU3rnLQLzcylP3WngXJTmfKH4EHtsCAwEAAaOCAtkwggLVMAkGA1UdEwQCMAAwCwYDVR0PBAQD AgSwMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDBDAdBgNVHQ4EFgQUQIwkgle9AaSwXl4H uQ14vpj4R00wHwYDVR0jBBgwFoAUU3Ltkpzg2ssBXHx+ljVO8tS4UYIwHgYDVR0RBBcwFYETZHdt dzJAaW5mcmFkZWFkLm9yZzCCAUwGA1UdIASCAUMwggE/MIIBOwYLKwYBBAGBtTcBAgMwggEqMC4G CCsGAQUFBwIBFiJodHRwOi8vd3d3LnN0YXJ0c3NsLmNvbS9wb2xpY3kucGRmMIH3BggrBgEFBQcC AjCB6jAnFiBTdGFydENvbSBDZXJ0aWZpY2F0aW9uIEF1dGhvcml0eTADAgEBGoG+VGhpcyBjZXJ0 aWZpY2F0ZSB3YXMgaXNzdWVkIGFjY29yZGluZyB0byB0aGUgQ2xhc3MgMSBWYWxpZGF0aW9uIHJl cXVpcmVtZW50cyBvZiB0aGUgU3RhcnRDb20gQ0EgcG9saWN5LCByZWxpYW5jZSBvbmx5IGZvciB0 aGUgaW50ZW5kZWQgcHVycG9zZSBpbiBjb21wbGlhbmNlIG9mIHRoZSByZWx5aW5nIHBhcnR5IG9i bGlnYXRpb25zLjA2BgNVHR8ELzAtMCugKaAnhiVodHRwOi8vY3JsLnN0YXJ0c3NsLmNvbS9jcnR1 MS1jcmwuY3JsMIGOBggrBgEFBQcBAQSBgTB/MDkGCCsGAQUFBzABhi1odHRwOi8vb2NzcC5zdGFy dHNzbC5jb20vc3ViL2NsYXNzMS9jbGllbnQvY2EwQgYIKwYBBQUHMAKGNmh0dHA6Ly9haWEuc3Rh cnRzc2wuY29tL2NlcnRzL3N1Yi5jbGFzczEuY2xpZW50LmNhLmNydDAjBgNVHRIEHDAahhhodHRw Oi8vd3d3LnN0YXJ0c3NsLmNvbS8wDQYJKoZIhvcNAQEFBQADggEBAFktijTezt72VbTR11aoG5oo 3qbSsLfvG+sohcE95CaMsCJz5eVPjnikWX0Ckx4ITODoaH+pRduOGTMYYq/8ae5f85GfwVG8S8Ke pCC9uxouaYD+Ayi502YXkC/TeWIv7zDjcTFnKXFvmTb+YZwwnxLH1XC1wvLDSz48dns3zCIUkj8A biaZjrp+9LXuBD9GAao0mpT373OXwuSoGmLakwxcKPTMNuV+RxwwtK+gSuWjaxdZw/8WE1+3Hb2W Vpe3FAKa+Dwq57iNgxJ+zlkP62ONO8rVdXOaY75rr/yE/2VG/5F1ekOO1L6yadiH4tlYbAXJxx2r Cmr47UQpqQ7BjK0xggNvMIIDawIBATCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2 BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMJ 2TIwCQYFKw4DAhoFAKCCAa8wGAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUx DxcNMTUwMjAxMTEyMDMzWjAjBgkqhkiG9w0BCQQxFgQUag8aB7SZ3lX2vhudOzcavTobmEkwgaUG CSsGAQQBgjcQBDGBlzCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0Q29tIEx0ZC4x KzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2BgNVBAMTL1N0 YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMJ2TIwgacGCyqG SIb3DQEJEAILMYGXoIGUMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRDb20gTHRkLjEr MCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYGA1UEAxMvU3Rh cnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0ECAwnZMjANBgkqhkiG 9w0BAQEFAASCAQDFG/jBxNnsS7t7Nmmqm3k2eM7V0fPwx0rbNHaUxyGfKPvPOBJoYKCpOP0x24OQ 27Uf8AIvmNc9ohGeZkI6SR/yzTGM2guvzkIs8U/aETKkZZcigWaK6N2oHlEvCJxMLu5Ap2fIrxJ9 Qj7Bww2n2H6+ffU6N0YRDTZ024Nm9h11lB6PfW6ZJV3w90NVOUzwI7OonCPtt/fn6mrkDYX/NcH0 B/cjvLmRTrPWIPBEglKIlLD29DXVBpe4llPoY6zfaxBcYetb8MolM3d3dkFrQ0b3Yue5CmvgGvu8 c7aK41ttJjTV+u5KVjIocBuoMA5qCkSVG17NxGPg7ssoFE5QuDDYAAAAAAAA --=-veIGnxzbfFksq7FaRHqw-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/