From patchwork Wed May 22 13:54:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Haakon Bugge X-Patchwork-Id: 13670884 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 D9E871420A2; Wed, 22 May 2024 13:55:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.165.32 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716386140; cv=none; b=ZuaN4UGFGVXQTUF4jUCKw5KV+5M+qiNxBNucjbmJWdwacwjDIB/e3bQrU9GoKd1UtFLuxfDsCZZHxT/vpbtiZ+pu37N7jABRcXyctpd0JVztHMAqrNRYCrk96gysySfSdqbo4V2SWyF6EUlrNGO8R7hnwrb4TqaSh/Mu9xA3JhE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716386140; c=relaxed/simple; bh=LbTyLk9OwJkqvxmgn+6ZY6LFKU7EWl4UGi9PWLrNn7k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=ckUehfPCWk/oaXyMv9xCHG3on6OESSrg9sTsDmyBvMsYDJy455KPmABoRVjH2+uGMoic8WFegWuppDEqXhkNpThovDj8bWobyq2inxaSvAlHShWdYIPELNydXOyd6nkwIl5C2R+k2DPBH9v/BX1ymF1QSF439+aSbOPMPOmrPEA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=OCZ3cQnV; arc=none smtp.client-ip=205.220.165.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="OCZ3cQnV" Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 44MCqkmT003018; Wed, 22 May 2024 13:55:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=corp-2023-11-20; bh=GMAoVtYiZLoLVeIZtnneE3D8HNGcJZTFwILjLvpvR3Q=; b=OCZ3cQnValq6pt+QhSc/KNnI4n+M7lBlCSSIHIPEZ/M2H+b3JFFs5b8TD+n717tBHHxQ lPjmTgbeTlj9LU51DE6YVpydMd5s5OPKQAhPhVaRV5fS186LnDCnNpyAkRVCZvqwHXZY /XjKAyH7M+aYtxxaPLaWUfuto9I4LdejLbtg/wnAkeKGQJ6ovJgk/3sUzsdYQCA2+YD4 mBVcO2VFUJOqnVXm80Sdn/cSSfk9vtqNjGGiLFABzyvZZJIF1iZzUIQKFIe6Rsxp7jh3 vMBCbdrymX6l0RWc1hY3ZoulXZ7tsnEzbF2/NESL9NMDNlQ2Fp45WMJI56+Z0VBLDGyi Fg== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3y6m7b7h0f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 22 May 2024 13:55:24 +0000 Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.19/8.17.1.19) with ESMTP id 44MCIPwd019528; Wed, 22 May 2024 13:55:23 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3y6js98thw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 22 May 2024 13:55:23 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 44MDsm3G016070; Wed, 22 May 2024 13:55:22 GMT Received: from lab61.no.oracle.com (lab61.no.oracle.com [10.172.144.82]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3y6js98su1-11; Wed, 22 May 2024 13:55:22 +0000 From: =?utf-8?q?H=C3=A5kon_Bugge?= To: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, rds-devel@oss.oracle.com Cc: Jason Gunthorpe , Leon Romanovsky , Saeed Mahameed , Tariq Toukan , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Tejun Heo , Lai Jiangshan , Allison Henderson , Manjunath Patil , Mark Zhang , =?utf-8?q?H=C3=A5kon_Bugge?= , Chuck Lever , Shiraz Saleem , Yang Li Subject: [PATCH v3 5/6] RDMA/mlx5: Brute force GFP_NOIO Date: Wed, 22 May 2024 15:54:42 +0200 Message-Id: <20240522135444.1685642-11-haakon.bugge@oracle.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20240522135444.1685642-1-haakon.bugge@oracle.com> References: <20240522135444.1685642-1-haakon.bugge@oracle.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.650,FMLib:17.12.28.16 definitions=2024-05-22_07,2024-05-22_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxscore=0 spamscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2405010000 definitions=main-2405220093 X-Proofpoint-ORIG-GUID: FG04WMcPX0Z_wfhlZlSwJW2V-VRH6ePq X-Proofpoint-GUID: FG04WMcPX0Z_wfhlZlSwJW2V-VRH6ePq In mlx5_ib_init(), we call memalloc_noio_{save,restore} in a parenthetic fashion when enabled by the module parameter force_noio. This in order to conditionally enable mlx5_ib to work aligned with I/O devices. Any work queued later on work-queues created during module initialization will inherit the PF_MEMALLOC_{NOIO,NOFS} flag(s), due to commit ("workqueue: Inherit NOIO and NOFS alloc flags"). We do this in order to enable ULPs using the RDMA stack and the mlx5_ib driver to be used as a network block I/O device. This to support a filesystem on top of a raw block device which uses said ULP(s) and the RDMA stack as the network transport layer. Under intense memory pressure, we get memory reclaims. Assume the filesystem reclaims memory, goes to the raw block device, which calls into the ULP in question, which calls the RDMA stack. Now, if regular GFP_KERNEL allocations in ULP or the RDMA stack require reclaims to be fulfilled, we end up in a circular dependency. We break this circular dependency by: 1. Force all allocations in the ULP and the relevant RDMA stack to use GFP_NOIO, by means of a parenthetic use of memalloc_noio_{save,restore} on all relevant entry points. 2. Make sure work-queues inherits current->flags wrt. PF_MEMALLOC_{NOIO,NOFS}, such that work executed on the work-queue inherits the same flag(s). Signed-off-by: Håkon Bugge --- drivers/infiniband/hw/mlx5/main.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index 2366c46eebc87..d47ef7d48f492 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -56,6 +56,10 @@ MODULE_AUTHOR("Eli Cohen "); MODULE_DESCRIPTION("Mellanox 5th generation network adapters (ConnectX series) IB driver"); MODULE_LICENSE("Dual BSD/GPL"); +static bool mlx5_ib_force_noio; +module_param_named(force_noio, mlx5_ib_force_noio, bool, 0444); +MODULE_PARM_DESC(force_noio, "Force the use of GFP_NOIO (Y/N)"); + struct mlx5_ib_event_work { struct work_struct work; union { @@ -4488,16 +4492,23 @@ static struct auxiliary_driver mlx5r_driver = { static int __init mlx5_ib_init(void) { + unsigned int noio_flags; int ret; + if (mlx5_ib_force_noio) + noio_flags = memalloc_noio_save(); + xlt_emergency_page = (void *)__get_free_page(GFP_KERNEL); - if (!xlt_emergency_page) - return -ENOMEM; + if (!xlt_emergency_page) { + ret = -ENOMEM; + goto out; + } mlx5_ib_event_wq = alloc_ordered_workqueue("mlx5_ib_event_wq", 0); if (!mlx5_ib_event_wq) { free_page((unsigned long)xlt_emergency_page); - return -ENOMEM; + ret = -ENOMEM; + goto out; } ret = mlx5_ib_qp_event_init(); @@ -4514,7 +4525,7 @@ static int __init mlx5_ib_init(void) ret = auxiliary_driver_register(&mlx5r_driver); if (ret) goto drv_err; - return 0; + goto out; drv_err: auxiliary_driver_unregister(&mlx5r_mp_driver); @@ -4525,6 +4536,9 @@ static int __init mlx5_ib_init(void) qp_event_err: destroy_workqueue(mlx5_ib_event_wq); free_page((unsigned long)xlt_emergency_page); +out: + if (mlx5_ib_force_noio) + memalloc_noio_restore(noio_flags); return ret; }