From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 504C349F102; Mon, 7 Sep 2026 10:52:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.165.32 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788778364; cv=fail; b=gNuFfL2fB7Quz9h7i0QZJexstXwjKhS75yBtDIkM/0ptl7P9F2a6vFi75GlO2ii/gBwb81GXcnuhIRMQyU95f+Sk7SSfM4YbVl5GXjTDVtAUz/kYQYjMsnkH50xXv3j8oFiO5pgcb88k6P89b+fqhQkSwtbZEe9S7imloX1JrlA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788778364; c=relaxed/simple; bh=avdacaS6XzmqXRJM3Sd6/Jiekpzj9H4UVti6oU4GBh0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=WSaWZXDe1jrUPyagTMhmvELbfomeoTQNSEa6NrOnrT3BC8iN3PzYr8r2QyAyBmvHWLBOuaozxZaKYWESLlkgz4DP5ILvc+ph8C3kX0jJTomQgrrX2nUh5LRTfxRR09DMXIzYxf9ueG35ewoOix8hAT6OO1dJTkKkDhCZ6R602Fs= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=ZNq6s1w+; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=bdp7yga6; arc=fail smtp.client-ip=205.220.165.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ZNq6s1w+"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="bdp7yga6" Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6873vFRE1033787; Mon, 7 Sep 2026 10:52:07 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=EHWLtWnlVItwvNDVIU/wu34YTqCvVj70IP/OcNTUg4A=; b= ZNq6s1w+ze9+uN8WC08zqLDB3RoaJ/FCmhCSMjnKqhAlu+z1E1AbJ+HVW7vWZdh/ Jss4QIC+wHPk5ZZbOVr7XQm+27+bkoPMON6FeDb8GXp3ictZRv9bxiGeG99Bl5Vx OyGYbqbpiHmi9Z5Nqs/J0HErHeqxEv9bBO90Sl5i5eIdmjWrWBOXH1UaMHX9Hwd7 gxKbGrMH09rW0jKnv8YJlYW6k7JB0NRqkPFB2o6yjO5y4tdHYZ/0+y4DQL2R9XiY AHdinPwgwSqVqVgCbT8hCSnVO/e0syI1Knf4yv7QjtuNupWnoHZmzODtaDZ6EKYp VbbIXiPOTOjSqECb1JCN2A== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4ggbd3st0c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 07 Sep 2026 10:52:07 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.7/8.18.1.7) with ESMTP id 687Apnin012930; Mon, 7 Sep 2026 10:52:06 GMT Received: from sa9pr02cu001.outbound.protection.outlook.com (mail-southcentralusazon11013056.outbound.protection.outlook.com [40.93.196.56]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4gh7atpvuh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 07 Sep 2026 10:52:05 +0000 (GMT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MtHncWBwY5z1+x0OMoSh21Tqkb8K3HBURBrtTTiWuBEzqq4pzb4se/r+unvt56eWAIX3/EwTNQvBvD0HUCgJoQUbmQepJVcor7FixdYAZ+sNcMNrMXi2qqUr9uC3EYXyPBj4mUWtSUN1tV03V2PpeIFZIl7Q0n47FTshc87KcBR7n1OyE0B0nT6doK0MpNIxdqHajlLeNboAxanujtQgnxLHGZwIx2BBHw/KopaiCJaFdhG2KCP5/ddKCTVnN5xLT49FRhtz3ioUkxu1AOm3sUGB5Zxzd5EP+JkfWn+qlfwxIDLB6gln0dakidktb7Ar/Evw1HsMlpJkCyHarJs2IA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=EHWLtWnlVItwvNDVIU/wu34YTqCvVj70IP/OcNTUg4A=; b=xNv6Hf0K1I1igvVGJF9GvjNxb55S50ay8fwa7Z1viPggLi6jYsm+RyBkinQABtwL1ITnSgPNyC9Z4aONbbPTavojk+00wjSxWA5PZOmpqIbt2Nw+nBC6Ix2N6GMWtVVcJW4BYRCUYjH3yF3fMrlJWp8Wf6rtpcfyUROhjhfeFsXupdaI1Uk1YjQsRZq5jOG6AelmbcPQXJkaeOOJatVoRXsnQhKN/aj3c8gRM6KBMQncDzIy0kYKu31dTg0uXEdO3r/+EHKFqpHfLaOoPLj53syrgJVVr92/WD10llVOfV+Rrnn5TzUwvp4o6Z4OIg4ioD0qSDRPuAp5xRFaoqaHmA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=EHWLtWnlVItwvNDVIU/wu34YTqCvVj70IP/OcNTUg4A=; b=bdp7yga6yQaiSVVi6c+Y1tp7/41z3NH4DjuJRv3PyrxeUp8y00jXk/oi3Z5XqLkbhLd+2NZk/k4/3RtF4L3ewDX1nLI8KFjX9rA2HVhoNVgrTrdoTCJ6ndyOK9268GvkP9lbsY12OjNBr0HysfNTXt/krcH4+QV8cGsTNJZxClk= Received: from DM4PR10MB6229.namprd10.prod.outlook.com (2603:10b6:8:8c::12) by SJ5PPFA7D84DD83.namprd10.prod.outlook.com (2603:10b6:a0f:fc02::7c0) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.406.6; Mon, 7 Sep 2026 10:50:40 +0000 Received: from DM4PR10MB6229.namprd10.prod.outlook.com ([fe80::867:63e7:13fa:fa7d]) by DM4PR10MB6229.namprd10.prod.outlook.com ([fe80::867:63e7:13fa:fa7d%6]) with mapi id 15.21.0406.005; Mon, 7 Sep 2026 10:50:40 +0000 From: John Garry To: james.bottomley@hansenpartnership.com, hare@suse.com, mkp@kernel.org Cc: jmeneghi@redhat.com, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, michael.christie@oracle.com, snitzer@kernel.org, bmarzins@redhat.com, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org, nilay@linux.ibm.com, john.garry@linux.dev, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me Subject: [PATCH v8 03/27] libmultipath: Add path selection support Date: Mon, 7 Sep 2026 10:49:57 +0000 Message-ID: <20260907105021.1763236-4-john.g.garry@oracle.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20260907105021.1763236-1-john.g.garry@oracle.com> References: <20260907105021.1763236-1-john.g.garry@oracle.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: PH0PR07CA0049.namprd07.prod.outlook.com (2603:10b6:510:e::24) To DM4PR10MB6229.namprd10.prod.outlook.com (2603:10b6:8:8c::12) Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR10MB6229:EE_|SJ5PPFA7D84DD83:EE_ X-MS-Office365-Filtering-Correlation-Id: ec2aed83-8bd1-4732-8fae-08df0ccddb80 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|7416014|23010399003|366016|6133799003|10067099003|56012099006|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR10MB6229.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(7416014)(23010399003)(366016)(6133799003)(10067099003)(56012099006)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?USzi8XSNLtJfOxHTTRcYM6FtsNRwzPqt86rhrBrHrWCMXd5VV/hx14AOXl+f?= =?us-ascii?Q?7gvmVxirDUN32ICXOhChWDnwS7qjQ4emWLqSctcJ6UmY4O1jeQRBoYUAvFOA?= =?us-ascii?Q?e5PFUpGPIle4K27Zv7hJ2FXlefyTxS61/rk759CrJE1xGteQjrc9JQP+vFoW?= =?us-ascii?Q?Y9V/EAYHx6bqN5+Bd5pvB3dg0fru2SMy78MH0Cvx6oFW/DM5ZzB892tP+kb2?= =?us-ascii?Q?KF5DVYgfU1xPB5Tr5pKFc107PFeXB1JBOsl20q8EFMjJSr5oQghzmjtAmjIh?= =?us-ascii?Q?FY36EAfqNzKLx5v3LjQY925Z0GgH+g4NPSbTcERV3ST3/t0Vde0f5jtMa9o0?= =?us-ascii?Q?ZqdGCXlm3+tmArqCGHvtMp8ku8mxrALuRiVP+HDhjW4xg0QoJhmTXu4nSMxU?= =?us-ascii?Q?AhmX7jM4RmXvkU/SzQvH9B0o5RBLy91+zafozmKrIhDDmO3VI4sW6T3QqFdk?= =?us-ascii?Q?y2NaPg9Onn8wAE2Y2BBC8hYWmX0x3ToN1xrFADq6ykAKGxoFi6AMr8jAvrfR?= =?us-ascii?Q?uMrt5eJU8i2saHQ3Xr2YmqitQL6Q2RaRcV3AxJnNVrs2YRwMFtEFq++qpL6Y?= =?us-ascii?Q?g9/fYZ6dwdHUjrF7U5JrKhixIHr9bUBDxpjWjT5wz/teDMz7VyMleTkv7iQu?= =?us-ascii?Q?+sZSvKqUhxms3SaS5l1OVnDCHkZEywi9smRMYxxi2/D78Nl7/edviD5rA5mf?= =?us-ascii?Q?4TN+1DxZfQVvRVKFKjp4Oppv67RIbFMChhONnEWEe7nPAAgplLRY0ReZGLFG?= =?us-ascii?Q?WQmBzLGPOk2VOSpCx8+EWORH0q92vPL+aRW53p7iH8q70Tpsg25Svou53OlQ?= =?us-ascii?Q?1F0BZLoyZtOt6b/7s6wGJsJZECd6T81IFiBZHBqiDemZx3jom7xU/yT5Ig9b?= =?us-ascii?Q?HiI3gOyOCCSD10s35rWsat9xk2jpTTPnWegg0ZgkxjErRjdwkStHGmN6RrLC?= =?us-ascii?Q?zjQJmCAcgxVx7++xXM1HizE+M7JnYBiREId8QG0Oio0P+fu8oXitT+rwMo+E?= =?us-ascii?Q?aOdA3UfRam7s7Vqw5Quqly7u4vAmDgN8F0lisYqIf7iHrHZ4tX+gCJyMMQBA?= =?us-ascii?Q?vPxBqf820GeZZhB0MorpxQIEcbM755OF754vkTKMo9H5HGJ7sK0JpI0zovqU?= =?us-ascii?Q?2zvKG8u1mqHfIcHvBtKMpkZKiJdetYEfsv7VA7Wy0HImnKgBMvarxIW62VJf?= =?us-ascii?Q?QyXdnbi3zuWZBotM/ox+GAHT7SxZ5avRWM/SLCh6VAfqnaVm2l+aMXGBqRZX?= =?us-ascii?Q?rK2AV3j8wbQv+YT0bW0k20OUB5RiBcWZI4W/vN8IyV+vES47AfZgRtLjwoXa?= =?us-ascii?Q?ChqQ0T6lzwAhoc9iA7FDRorX1jZtZv2AprC7x4HvHEH9kId9x1EvUrIxY63N?= =?us-ascii?Q?cP+JSKHnE31ZQ3KGq/fT/175MuaquHiO03v3gHm/tR1cGl8gMSvK2QOh1HiW?= =?us-ascii?Q?7Gax72jplXy3umrUTRNGXA1or82iEw+turq3G9x9URL6/afcwYzLr2dR69zx?= =?us-ascii?Q?2ZA/6yGlMbXgZG2eXEMgjRnGiBdDCZNU7vdmM6INBfipa9YFXF3xLQP1St6N?= =?us-ascii?Q?MtLZL27lUmMIv/UK/IUcHzeIXqctS1mzJJk3pMrOy0bv7oUL69L56FjVBENF?= =?us-ascii?Q?t4uEajvLSeGXkTvK44IFec6clPoA2BKWjBe9GjzdqzDjTc2OF5lma15d6JC4?= =?us-ascii?Q?xwFshYFn/IXH5XlI9lNAZC6sGsaEZriPeOhuMC8bdbZNlPEk9GZ5oH1Ycbrs?= =?us-ascii?Q?bumAMhatfI6oXB3wGRueUiuLLkBFDFs=3D?= X-Exchange-RoutingPolicyChecked: b/GCF6phi+h9VqTSAAp5tj18pNS90I1ly0XBMIHTOKZDUQcZh9FGDEfs5fSw2QE+jRJytGy1jZsq3u8msQB37d6u/fSghwnCpnT479pXOEYJjqzq+0YD0A06xaCxdKiSzthUed4TnrBi/fQA36zDbULYn3bp+wuHi7ut2ZOasTBliw/bC/+EED3ds5XJ45NrptKVJkuj5qj20/z+3wXg7Krd7SyqOEEUtgmLNejewOpyb0ZkRhVtDqMJ6/KbVaZlKfHGDScTRaAvJOlJrDngGhg5DDdYJfp+8+v3ZbxpW54YX5L7TojIM9t257FDJ3z9IKpZD0sAy7AjM7zPyJJZ4A== X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: ec2aed83-8bd1-4732-8fae-08df0ccddb80 X-MS-Exchange-CrossTenant-AuthSource: DM4PR10MB6229.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Sep 2026 10:50:40.2210 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 6WX1fTy57rRcMm/hsoXTwustSbApX6JBa+kvZtBUwSqARvP+jGCx3UnqD7+Vyucm1ark9n97EUOGLgzLmLZk8w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ5PPFA7D84DD83 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-07_03,2026-09-07_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 suspectscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0 bulkscore=0 malwarescore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2606160000 definitions=main-2609070119 X-Authority-Analysis: v=2.4 cv=EuDiaycA c=1 sm=1 tr=0 ts=6a9e9757 b=1 cx=c_pps a=qoll8+KPOyaMroiJ2sR5sw==:117 a=qoll8+KPOyaMroiJ2sR5sw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=VdqzKS8jKosA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=jiCTI4zE5U7BLdzWsZGv:22 a=EIcjfB9IiI4px24ztqRk:22 a=Lb5UtHSxAhypNmDEWQsA:9 a=5yU3S35YU4bGjq-dph-N:22 a=Bho9c0fBagfJEIQBS7DQ:22 cc=ntf awl=host:12102 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA3MDExOCBTYWx0ZWRfX4qVHnMoRPXhe iG8n+hl3wYtHzPOt5UNhvbZgan37J8iN0BNoOQZck3SM7VoU2CF6YMREaIj56iwUgB2tqdKmFvg oJyPh5bHFwweipDQPUNVsHRbwok2jMGbd6BrztRv8wF+k784dxcl X-Proofpoint-GUID: Hvb9CfWemuYOoadXCwlFnf_Xg4966XRZ X-Proofpoint-ORIG-GUID: Hvb9CfWemuYOoadXCwlFnf_Xg4966XRZ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA3MDExOCBTYWx0ZWRfX3zEGKlWdBhJw 1RKdZlqsKaFRtA8sRu+zkTe+U8zNq5g1To2yTKcdyTL4w9zwXenCLRSHcMPlUkAt1an+OZpGzMm 1VM0dapfGWF3htpK3uQck9IwLxmTp3kq1e0mn5HGxae9L+Ly9Gd9zHdlMJs0veyOmMj7GP4/JCv r0QeB5YDJCk293NFUF0jdfEyauuO6f1kWCG8UhaTtBSaR6aW06iZt25/3xU0YksR4WQ/BPoMDwi INJrFJLxDtn8uSOLPgC/a56oLjzoQAJGtllSWHOSOk1VDdMg+HwRV314RUJK2qvCSx8HBXt+GkG a0dp2ioIkmuyQ9nZ6acofhnZvvNGrQxU/yCCVpz+A6VwMNDZu/51CivihNiFGPCpPVnhm72f7Iy VhAzO+MxkGwc9gtPev/Orgxl8T7lOKLprHZtxvnTowaCOn0wli9HIQFj/Cgap2RmPEDkJ/gfiZg qeLuOIH9IyPXrdNFtcbxJ0tezWCjimL5RRu/Kz24= From: John Garry Add code for path selection. NVMe ANA is abstracted into enum mpath_access_state. The motivation here is so that SCSI ALUA can be used. Callbacks .is_disabled and .is_optimized are added to get the path access state. Path selection modes round-robin, NUMA, and queue-depth are added, same as NVMe supports. NVMe has almost like-for-like equivalents here: - __mpath_find_path() -> __nvme_find_path() - mpath_find_path() -> nvme_find_path() and similar for all introduced callee functions. Functions mpath_set_iopolicy() and mpath_get_iopolicy() are added for setting default iopolicy. Signed-off-by: John Garry --- include/linux/multipath.h | 33 +++++ lib/multipath.c | 251 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 284 insertions(+) diff --git a/include/linux/multipath.h b/include/linux/multipath.h index ca6e02505be43..9bbab0aa8961a 100644 --- a/include/linux/multipath.h +++ b/include/linux/multipath.h @@ -7,13 +7,31 @@ extern const struct block_device_operations mpath_ops; +enum mpath_iopolicy_e { + MPATH_IOPOLICY_NUMA, + MPATH_IOPOLICY_RR, + MPATH_IOPOLICY_QD, +}; + +enum mpath_access_state { + MPATH_STATE_OPTIMIZED, + MPATH_STATE_NONOPTIMIZED, + MPATH_STATE_OTHER +}; + struct mpath_device { struct mpath_head *mpath_head; struct list_head siblings; struct gendisk *disk; + int numa_node; + atomic_t *nr_active; + enum mpath_access_state access_state; }; struct mpath_head_template { + bool (*is_disabled)(struct mpath_device *); + bool (*is_optimized)(struct mpath_device *); + const struct attribute_group **device_groups; }; #define MPATH_HEAD_DISK_LIVE 0 @@ -25,6 +43,7 @@ struct mpath_head { refcount_t refcount; + enum mpath_iopolicy_e *iopolicy; unsigned long flags; struct gendisk *disk; struct work_struct partition_scan_work; @@ -44,6 +63,14 @@ static inline struct mpath_head *mpath_gendisk_to_head(struct gendisk *disk) return mpath_bd_device_to_head(disk_to_dev(disk)); } +static inline enum mpath_iopolicy_e mpath_read_iopolicy( + struct mpath_head *mpath_head) +{ + return READ_ONCE(*mpath_head->iopolicy); +} +void mpath_synchronize(struct mpath_head *mpath_head); +int mpath_set_iopolicy(const char *str, enum mpath_iopolicy_e *iopolicy); +int mpath_get_iopolicy(char *buf, int iopolicy); int mpath_get_head(struct mpath_head *mpath_head); void mpath_put_head(struct mpath_head *mpath_head); int mpath_head_init(struct mpath_head *mpath_head); @@ -63,4 +90,10 @@ static inline bool is_mpath_disk(struct gendisk *disk) return false; #endif } + +static inline bool mpath_qd_iopolicy(enum mpath_iopolicy_e *iopolicy) +{ + return READ_ONCE(*iopolicy) == MPATH_IOPOLICY_QD; +} + #endif // _LIBMULTIPATH_H diff --git a/lib/multipath.c b/lib/multipath.c index 574868ce53381..3541357d07f8d 100644 --- a/lib/multipath.c +++ b/lib/multipath.c @@ -7,8 +7,245 @@ #include #include +static struct mpath_device *mpath_find_path(struct mpath_head *mpath_head); + static struct workqueue_struct *mpath_wq; +static const char * const mpath_iopolicy_names[] = { + [MPATH_IOPOLICY_NUMA] = "numa", + [MPATH_IOPOLICY_RR] = "round-robin", + [MPATH_IOPOLICY_QD] = "queue-depth", +}; + +static int mpath_iopolicy_parse(const char *str) +{ + return __sysfs_match_string(mpath_iopolicy_names, + ARRAY_SIZE(mpath_iopolicy_names), str); +} + +int mpath_set_iopolicy(const char *str, enum mpath_iopolicy_e *iopolicy) +{ + int policy; + + if (!str) + return -EINVAL; + policy = mpath_iopolicy_parse(str); + if (policy < 0) + return policy; + WRITE_ONCE(*iopolicy, policy); + + return 0; +} +EXPORT_SYMBOL_GPL(mpath_set_iopolicy); + +int mpath_get_iopolicy(char *buf, int iopolicy) +{ + return sprintf(buf, "%s\n", mpath_iopolicy_names[iopolicy]); +} +EXPORT_SYMBOL_GPL(mpath_get_iopolicy); + + +void mpath_synchronize(struct mpath_head *mpath_head) +{ + synchronize_srcu(&mpath_head->srcu); +} +EXPORT_SYMBOL_GPL(mpath_synchronize); + +static bool mpath_path_is_disabled(struct mpath_head *mpath_head, + struct mpath_device *mpath_device) +{ + return mpath_head->mpdt->is_disabled(mpath_device); +} + +static struct mpath_device *__mpath_find_path(struct mpath_head *mpath_head, + int node) +{ + int found_distance = INT_MAX, fallback_distance = INT_MAX, distance; + struct mpath_device *found = NULL, *fallback = NULL, *mpath_device; + + list_for_each_entry_srcu(mpath_device, &mpath_head->dev_list, siblings, + srcu_read_lock_held(&mpath_head->srcu)) { + if (mpath_path_is_disabled(mpath_head, mpath_device)) + continue; + + if (mpath_device->numa_node != NUMA_NO_NODE && + (mpath_read_iopolicy(mpath_head) == + MPATH_IOPOLICY_NUMA)) + distance = node_distance(node, + mpath_device->numa_node); + else + distance = LOCAL_DISTANCE; + + switch(mpath_device->access_state) { + case MPATH_STATE_OPTIMIZED: + if (distance < found_distance) { + found_distance = distance; + found = mpath_device; + } + break; + case MPATH_STATE_NONOPTIMIZED: + if (distance < fallback_distance) { + fallback_distance = distance; + fallback = mpath_device; + } + break; + default: + break; + } + } + + if (!found) + found = fallback; + + if (found) + rcu_assign_pointer(mpath_head->current_path[node], found); + + return found; +} + +static struct mpath_device *mpath_next_dev(struct mpath_head *mpath_head, + struct mpath_device *mpath_dev) +{ + mpath_dev = list_next_or_null_rcu(&mpath_head->dev_list, + &mpath_dev->siblings, struct mpath_device, + siblings); + + if (mpath_dev) + return mpath_dev; + return list_first_or_null_rcu(&mpath_head->dev_list, + struct mpath_device, siblings); +} + +static struct mpath_device *mpath_round_robin_path( + struct mpath_head *mpath_head) +{ + struct mpath_device *mpath_device, *found = NULL; + int node = numa_node_id(); + enum mpath_access_state access_state_old; + struct mpath_device *old = + srcu_dereference(mpath_head->current_path[node], + &mpath_head->srcu); + + if (unlikely(!old)) + return __mpath_find_path(mpath_head, node); + + if (list_is_singular(&mpath_head->dev_list)) { + if (mpath_path_is_disabled(mpath_head, old)) + return NULL; + return old; + } + + for (mpath_device = mpath_next_dev(mpath_head, old); + mpath_device && mpath_device != old; + mpath_device = mpath_next_dev(mpath_head, mpath_device)) { + + if (mpath_path_is_disabled(mpath_head, mpath_device)) + continue; + if (mpath_device->access_state == MPATH_STATE_OPTIMIZED) { + found = mpath_device; + goto out; + } + if (mpath_device->access_state == MPATH_STATE_NONOPTIMIZED) + found = mpath_device; + } + + /* + * The loop above skips the current path for round-robin semantics. + * Fall back to the current path if either: + * - no other optimized path found and current is optimized, + * - no other usable path found and current is usable. + */ + access_state_old = old->access_state; + if (!mpath_path_is_disabled(mpath_head, old) && + (access_state_old == MPATH_STATE_OPTIMIZED || + (!found && access_state_old == MPATH_STATE_NONOPTIMIZED))) + return old; + + if (!found) + return NULL; +out: + rcu_assign_pointer(mpath_head->current_path[node], found); + + return found; +} + +static struct mpath_device *mpath_queue_depth_path( + struct mpath_head *mpath_head) +{ + struct mpath_device *best_opt = NULL, *mpath_device; + struct mpath_device *best_nonopt = NULL; + unsigned int min_depth_opt = UINT_MAX, min_depth_nonopt = UINT_MAX; + unsigned int depth; + + list_for_each_entry_srcu(mpath_device, &mpath_head->dev_list, siblings, + srcu_read_lock_held(&mpath_head->srcu)) { + + if (mpath_path_is_disabled(mpath_head, mpath_device)) + continue; + + depth = atomic_read(mpath_device->nr_active); + + switch (mpath_device->access_state) { + case MPATH_STATE_OPTIMIZED: + if (depth < min_depth_opt) { + min_depth_opt = depth; + best_opt = mpath_device; + } + break; + case MPATH_STATE_NONOPTIMIZED: + if (depth < min_depth_nonopt) { + min_depth_nonopt = depth; + best_nonopt = mpath_device; + } + break; + default: + break; + } + + if (min_depth_opt == 0) + return best_opt; + } + + return best_opt ? best_opt : best_nonopt; +} + +static inline bool mpath_path_is_optimized(struct mpath_head *mpath_head, + struct mpath_device *mpath_device) +{ + return mpath_head->mpdt->is_optimized(mpath_device); +} + +static struct mpath_device *mpath_numa_path(struct mpath_head *mpath_head) +{ + int node = numa_node_id(); + struct mpath_device *mpath_device; + + mpath_device = srcu_dereference(mpath_head->current_path[node], + &mpath_head->srcu); + if (unlikely(!mpath_device)) + return __mpath_find_path(mpath_head, node); + if (unlikely(mpath_path_is_disabled(mpath_head, mpath_device))) + return __mpath_find_path(mpath_head, node); + if (unlikely(!mpath_path_is_optimized(mpath_head, mpath_device))) + return __mpath_find_path(mpath_head, node); + return mpath_device; +} + +__maybe_unused +static struct mpath_device *mpath_find_path(struct mpath_head *mpath_head) +{ + enum mpath_iopolicy_e iopolicy = mpath_read_iopolicy(mpath_head); + + switch (iopolicy) { + case MPATH_IOPOLICY_QD: + return mpath_queue_depth_path(mpath_head); + case MPATH_IOPOLICY_RR: + return mpath_round_robin_path(mpath_head); + default: + return mpath_numa_path(mpath_head); + } +} + int mpath_get_head(struct mpath_head *mpath_head) { if (!refcount_inc_not_zero(&mpath_head->refcount)) @@ -76,6 +313,7 @@ void mpath_remove_disk(struct mpath_head *mpath_head) if (test_and_clear_bit(MPATH_HEAD_DISK_LIVE, &mpath_head->flags)) { struct gendisk *disk = mpath_head->disk; + mpath_synchronize(mpath_head); del_gendisk(disk); } } @@ -133,6 +371,19 @@ void mpath_device_set_live(struct mpath_device *mpath_device) } queue_work(mpath_wq, &mpath_head->partition_scan_work); } + + mutex_lock(&mpath_head->lock); + if (mpath_path_is_optimized(mpath_head, mpath_device)) { + int node, srcu_idx; + + srcu_idx = srcu_read_lock(&mpath_head->srcu); + for_each_online_node(node) + __mpath_find_path(mpath_head, node); + srcu_read_unlock(&mpath_head->srcu, srcu_idx); + } + mutex_unlock(&mpath_head->lock); + + mpath_synchronize(mpath_head); } EXPORT_SYMBOL_GPL(mpath_device_set_live); -- 2.43.7