From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f178.google.com ([209.85.223.178]:35635 "EHLO mail-ie0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751098AbbGML61 (ORCPT ); Mon, 13 Jul 2015 07:58:27 -0400 Received: by iecuq6 with SMTP id uq6so233159610iec.2 for ; Mon, 13 Jul 2015 04:58:26 -0700 (PDT) Received: from [127.0.0.1] (rrcs-70-62-41-24.central.biz.rr.com. [70.62.41.24]) by smtp.googlemail.com with ESMTPSA id w75sm7986337iod.34.2015.07.13.04.58.25 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 Jul 2015 04:58:25 -0700 (PDT) Message-ID: <55A3A7DF.8080009@gmail.com> Date: Mon, 13 Jul 2015 07:58:23 -0400 From: Austin S Hemmelgarn MIME-Version: 1.0 To: linux-btrfs Subject: [RFC] Add an option to disable automatic chunk reclamation. Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms040605000600010302030705" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a cryptographically signed message in MIME format. --------------ms040605000600010302030705 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Since upgrading to a kernel with the automatic chunk reclamation=20 patches, I've noticed a number of issues with BTRFS that all seem to=20 either be caused by, or are further exacerbated by, this 'feature'. The four big issues I've seen regarding it are: 1. TRIM/DISCARD support is broken as a (partial?) result of this. 2. It appears to expose underlying issues with the defrag code (stuff=20 ending up more fragmented after defrag). 3. Since upgrading to a kernel with this patch, most of the BTRFS=20 filesystems that I have that are very rewrite heavy have gotten very=20 noticeably slower that they were beforehand (and this goes away when I=20 run them on a kernel without auto-reclaim). 4. All of my filesystems are experiencing seemingly non-deterministic=20 delays around most large scale VFS level operations (eg, deleting or=20 relocating lots of files) While I understand that this feature does solve (at least partially) an=20 very real issue with BTRFS, there were a number of people who never had=20 this issue to begin with because we ran regular balance operations on=20 our filesystems. Based on this, I would like to propose that some method be provided to=20 disable auto-reclaim be added. Personally, I would prefer to leave it=20 as the default and have a mount option to disable it. --------------ms040605000600010302030705 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIGuDCC BrQwggScoAMCAQICAxBuVTANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNTAz MjUxOTM0MzhaFw0xNTA5MjExOTM0MzhaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCdD/zW 2rRAFCLnDfXpWxU1+ODqRVUgzHvrRO7ADUxRo1CBDc3JSX5TIW2OGmQ3DAKGOACp8Z0sgxMc B05tzAZ/M7m4jajVrwwdVCdrwVGxTdAai7Kwg4ZCVfyMVhcwo8R2eW3QahBx34G0RKumK9sZ ZQSQ+zULAzpY6uz7T1sAk/erMoivRXF6u8WvOsLkOD1F/Xyv1ZccSUG5YeDgZgc0nZUBvyIp zXSHjgWerFkrxEM3y2z/Ff3eL1sgGYecV/I1F+I5S01V7Kclt/qRW10c/4JEGRcI1FmrJBPu BtMYPbg/3Y9LZROYN+mVIFxZxOfrmjfFZ96xt/TaMXo8vcEKtWcNEjhGBjEbfMUEm4aq8ygQ 4MuEcpJc8DJCHBkg2KBk13DkbU2qNepTD6Uip1C+g+KMr0nd6KOJqSH27ZuNY4xqV4hIxFHp ex0zY7mq6fV2o6sKBGQzRdI20FDYmNjsLJwjH6qJ8laxFphZnPRpBThmu0AjuBWE72GnI1oA aO+bs92MQGJernt7hByCnDO82W/ykbVz+Ge3Sax8NY0m2Xdvp6WFDY/PjD9CdaJ9nwQGsUSa N54lrZ2qMTeCI9Vauwf6U69BA42xgk65VvxvTNqji+tZ4aZbarZ7el2/QDHOb/rRwlCFplS/ z4l1f1nOrE6bnDl5RBJyW3zi74P6GwIDAQABo4IBWTCCAVUwDAYDVR0TAQH/BAIwADBWBglg hkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg b3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYDVR0PAQH/BAQDAgOoMEAGA1UdJQQ5 MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AuY2FjZXJ0Lm9y ZzAxBgNVHR8EKjAoMCagJKAihiBodHRwOi8vY3JsLmNhY2VydC5vcmcvcmV2b2tlLmNybDA0 BgNVHREELTArgRRhaGZlcnJvaW43QGdtYWlsLmNvbYETYWhlbW1lbGdAb2hpb2d0LmNvbTAN BgkqhkiG9w0BAQ0FAAOCAgEAGvl7xb42JMRH5D/vCIDYvFY3dR2FPd5kmOqpKU/fvQ8ovmJa p5N/FDrsCL+YdslxPY+AAn78PYmL5pFHTdRadT++07DPIMtQyy2qd+XRmz6zP8Il7vGcEDmO WmMLYMq4xV9s/N7t7JJp6ftdIYUcoTVChUgilDaRWMLidtslCdRsBVfUjPb1bF5Ua31diKDP e0M9/e2CU36rbcTtiNCXhptMigzuL3zJXUf2B9jyUV8pnqNEQH36fqJ7YTBLcpq3aYa2XbAH Hgx9GehJBIqwspDmhPCFZ/QmqUXCkt+XfvinQ2NzKR6P3+OdYbwqzVX8BdMeojh7Ig8x/nIx mQ+/ufstL1ZYp0bg13fyK/hPYSIBpayaC76vzWovkIm70DIDRIFLi20p/qTd7rfDYy831Hjm +lDdCECF9bIXEWFk33kA97dgQIMbf5chEmlFg8S0e4iw7LMjvRqMX3eCD8GJ2+oqyZUwzZxy S0Mx+rBld5rrN7LsXwZ671HsGqNeYbYeU25e7t7/Gcc6Bd/kPfA+adEuUGFcvUKH3trDYqNq 6mOkAd8WO/mQadlc3ztS++XDMhmIpfBre9MPAr6usqf+wc+R8Nk9KLK39kEgrqVfzc/fgf8L MaD4rHnusdg4gca6Yi+kNrm99anw7SwaBrBvULYBp7ixNRUhaYiNW4YjTrYxggShMIIEnQIB ATCBgDB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5v cmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEW EnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5VMAkGBSsOAwIaBQCgggH1MBgGCSqGSIb3DQEJAzEL BgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MDcxMzExNTgyM1owIwYJKoZIhvcNAQkE MRYEFMBsO/O3eYMU+PCOC0G52rgGZZuIMGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEq MAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwIC AUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgZEGCSsGAQQBgjcQBDGBgzCBgDB5MRAwDgYD VQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMT GUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2Fj ZXJ0Lm9yZwIDEG5VMIGTBgsqhkiG9w0BCRACCzGBg6CBgDB5MRAwDgYDVQQKEwdSb290IENB MR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2ln bmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5V MA0GCSqGSIb3DQEBAQUABIICAFHfXhEI7xrpSmM5pWxgMfA+JKFYoByvK9R39FMDrsEaFJWB 6UmAeY5yoDyI6jFn7UHXQZJ/kWcNyd3ZCjgddcYSbaa8qEyvW/utTyHaMdWnVAP8RSbZBP8W Y8BeakTPNi5QUlTSVdAuYqJELZZxdFDMJPLZTvciYFE56ZhJOeF4kdXaJQe31Lv+FpRjNjsz G9wzMYvD7wZjJkRdrted4w7VXXzN7OdrXfPeLbpedu/NeKqVDxoq5Mu+F3U6MUcEzSpzpZ9N Hwvjh9C5oyt+wIZgAkUXPRojPmh2M12j6rnbkaP5QEc2FqNiE6h9Vhj/z4Ju9SngcVBU2mT0 AiERpm+e5s103niwAiYkPw/+Xqc2e8EJjbGiAiJkLiZaQFGr06X9za6MpFe2bDnOSGfiM1r4 0FpHdw+4MH+wfG01UCIQ5SRbUVU0njireizS3mouc+P5y1nG10agDcD5a2UuL/Th0iu57TSL gg8ZzLYsw3+0H2Gi8PS2+qPyuOoTyAr8BONmWtnSIraxR8+6o7nyIA8cTwU+DfoRrmz1TWJP PWDxU3x3DWqyhCGOxcBq4Zpxh+LAd48mIXlPZUiGK4/hh8L2nzFzoRgp0d4H3NHkywJTCd18 Y8KdAPnlbw4+1XKee0VbQ2B1bzK8CuAKJEmbvxmkVFBtz6PLOCSQtWwnR8vPAAAAAAAA --------------ms040605000600010302030705--