From patchwork Thu Mar 24 20:22:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Parav Pandit X-Patchwork-Id: 8664631 Return-Path: X-Original-To: patchwork-linux-rdma@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3D5BB9F44D for ; Thu, 24 Mar 2016 20:24:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2253F200CF for ; Thu, 24 Mar 2016 20:24:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 713132038A for ; Thu, 24 Mar 2016 20:24:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752325AbcCXUYl (ORCPT ); Thu, 24 Mar 2016 16:24:41 -0400 Received: from mail-pa0-f41.google.com ([209.85.220.41]:34489 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953AbcCXUYf (ORCPT ); Thu, 24 Mar 2016 16:24:35 -0400 Received: by mail-pa0-f41.google.com with SMTP id fe3so30591172pab.1; Thu, 24 Mar 2016 13:24:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=bfQGrT6n9ygwkXoZOzcpG4GwZpFwg0Znp2xl5OkPOC0=; b=qh2ZaE0y3it71LwvuL11BTgBBTMaC+oYK8khezZTt4Kso4r0+z7f4hbPHf+GJvroeS +R41IUnO7o9HREqFQ3GodXluGpdZZv5bjLcHW4gVK2THjDr2LBMq4yAA5heIl39/BeCk hoKOP6qLHgfYR1XlcFOq7iQgt8pxdWSDXVngTvhiTp9b42JVxm2V3X066g2kAi3J10mA KVAJKaAEniBaVKNPUshfiOY2dxNax0xr2cKcnCXFB0N7iIpuH++oNtaNJbnjoQOjvKLC mNdlEQ204A6BSHYTSlgmJz98GS284uHETujtjEoBAkgSXVQMefjx+MJM028Fw8X3e1OK rVmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=bfQGrT6n9ygwkXoZOzcpG4GwZpFwg0Znp2xl5OkPOC0=; b=SvDVdhvYedziQnIAriUeDUP3UhFmHmEADPy2HqXTYP32qc98LfQmC8a+25Ng5zsvZF LNNP2rzegS6YTnlCCPwzGxrGRfGePflLLB4YrtAPfm13o6IR4d0+FRA0L+jb4Icus+h5 RgrJpWIYKhI09zK3+P59uaZQvS/mTsiaayOBjb7jnTmI0LJ/SMx9PBWRYZ95wS0DgNoB 9GiDR0yRhgHyOcqRH4qwxHfqYo5O+n4tfsFEYqcz7qNrRYU9odYpw/XxrEDh0Ib89k3u qJaGKDvpE15Q7aJ+4462uVi8xeVei2apozSrPPL/1R0rRhXdfpc+kyLbcFrCryPMooCv U3gg== X-Gm-Message-State: AD7BkJJNdidOSKrKTbgY0yDJrYyztMS3sTednSh3U3g7BVfsEni3SvUdq+G21PEwdpgBaw== X-Received: by 10.66.199.66 with SMTP id ji2mr15648142pac.34.1458851074537; Thu, 24 Mar 2016 13:24:34 -0700 (PDT) Received: from server1.localdomain ([106.206.129.143]) by smtp.gmail.com with ESMTPSA id k65sm11976779pfb.30.2016.03.24.13.24.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Mar 2016 13:24:33 -0700 (PDT) From: Parav Pandit To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, dledford@redhat.com, liranl@mellanox.com, sean.hefty@intel.com, jgunthorpe@obsidianresearch.com, haggaie@mellanox.com Cc: corbet@lwn.net, james.l.morris@oracle.com, serge@hallyn.com, ogerlitz@mellanox.com, matanb@mellanox.com, akpm@linux-foundation.org, linux-security-module@vger.kernel.org, pandit.parav@gmail.com Subject: [PATCHv10 3/3] rdmacg: Added documentation for rdmacg Date: Fri, 25 Mar 2016 01:52:42 +0530 Message-Id: <1458850962-16057-4-git-send-email-pandit.parav@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1458850962-16057-1-git-send-email-pandit.parav@gmail.com> References: <1458850962-16057-1-git-send-email-pandit.parav@gmail.com> MIME-Version: 1.0 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Added documentation for v1 and v2 version describing high level design and usage examples on using rdma controller. Signed-off-by: Parav Pandit --- Documentation/cgroup-v1/rdma.txt | 123 +++++++++++++++++++++++++++++++++++++++ Documentation/cgroup-v2.txt | 43 ++++++++++++++ 2 files changed, 166 insertions(+) create mode 100644 Documentation/cgroup-v1/rdma.txt diff --git a/Documentation/cgroup-v1/rdma.txt b/Documentation/cgroup-v1/rdma.txt new file mode 100644 index 0000000..f5e0a54 --- /dev/null +++ b/Documentation/cgroup-v1/rdma.txt @@ -0,0 +1,123 @@ + RDMA Controller + ---------------- + +Contents +-------- + +1. Overview + 1-1. What is RDMA controller? + 1-2. Why RDMA controller needed? + 1-3. How is RDMA controller implemented? +2. Usage Examples + +1. Overview + +1-1. What is RDMA controller? +----------------------------- + +RDMA controller allows user to limit RDMA/IB specific resources +that a given set of processes can use. These processes are grouped using +RDMA controller. + +RDMA controller allows operating on resources defined by the IB stack +which are mainly IB verb resources and in future hardware specific +well defined resources. + +1-2. Why RDMA controller needed? +-------------------------------- + +Currently user space applications can easily take away all the rdma device +specific resources such as AH, CQ, QP, MR etc. Due to which other applications +in other cgroup or kernel space ULPs may not even get chance to allocate any +rdma resources. This leads to service unavailability. + +Therefore RDMA controller is needed through which resource consumption +of processes can be limited. Through this controller various different rdma +resources described by IB stack can be accounted. + +1-3. How is RDMA controller implemented? +---------------------------------------- + +RDMA cgroup allows limit configuration of resources. These resources are not +defined by the rdma controller. Instead they are defined by the IB stack. +This provides great flexibility to allow IB stack to define additional +resources without any changes to rdma cgroup. +Rdma cgroup maintains resource accounting per cgroup, per device using +resource pool structure. Each such resource pool is limited up to +64 resources in given resource pool by rdma cgroup, which can be extended +later if required. + +This resource pool object is linked to the cgroup css. Typically there +are 0 to 4 resource pool instances per cgroup, per device in most use cases. +But nothing limits to have it more. At present hundreds of RDMA devices per +single cgroup may not be handled optimally, however there is no +known use case for such configuration either. + +Since RDMA resources can be allocated from any process and can be freed by any +of the child processes which shares the address space, rdma resources are +always owned by the creator cgroup css. This allows process migration from one +to other cgroup without major complexity of transferring resource ownership; +because such ownership is not really present due to shared nature of +rdma resources. Linking resources around css also ensures that cgroups can be +deleted after processes migrated. This allow progress migration as well with +active resources, even though that’s not the primary use case. + +Whenever RDMA resource charing occurs, owner rdma cgroup is returned to +the caller. Same rdma cgroup should be passed while uncharging the resource. +This also allows process migrated with active RDMA resource to charge +to new owner cgroup for new resource. It also allows to uncharge resource of +a process from previously charged cgroup which is migrated to new cgroup, +even though that is not a primary use case. + +Resource pool object is created in following situations. +(a) User sets the limit and no previous resource pool exist for the device +of interest for the cgroup. +(b) No resource limits were configured, but IB/RDMA stack tries to +charge the resource. So that it correctly uncharge them when applications are +running without limits and later on when limits are enforced during uncharging, +otherwise usage count will drop to negative. + +Resource pool is destroyed if it all the resource limits are set to max +and it is the last resource getting deallocated. + +User should set all the limit to max value if it intents to remove/unconfigure +the resource pool for a particular device. + +IB stack honors limits enforced by the rdma controller. When application +query about maximum resource limits of IB device, it returns minimum of +what is configured by user for a given cgroup and what is supported by +IB device. + +Following resources can be accounted. + uctx Maximum number of User Contexts + pd Maximum number of Protection domains + ah Maximum number of Address handles + mr Maximum number of Memory Regions + mw Maximum number of Memory Windows + cq Maximum number of Completion Queues + srq Maximum number of Shared Receive Queues + qp Maximum number of Queue Pairs + flow Maximum number of Flows + + +2. Usage Examples +----------------- + +(a) Configure resource limit: +echo mlx4_0 mr=100 qp=10 ah=2 > /sys/fs/cgroup/rdma/1/rdma.max +echo ocrdma1 mr=120 qp=20 cq=10 > /sys/fs/cgroup/rdma/2/rdma.max + +(b) Query resource limit: +cat /sys/fs/cgroup/rdma/2/rdma.max +#Output: +mlx4_0 uctx=max pd=max ah=2 mr=100 mw=max cq=max srq=max qp=10 flow=max +ocrdma1 uctx=1 pd=5 ah=1 mr=10 cq=10 srq=max qp=20 flow=max flow=max + +(c) Query current usage: +cat /sys/fs/cgroup/rdma/2/rdma.current +#Output: +mlx4_0 uctx=1 pd=2 ah=2 mr=95 mw=0 cq=2 srq=0 qp=8 flow=0 +ocrdma1 uctx=1 pd=6 ah=9 mr=20 mw=0 cq=1 srq=0 qp=2 flow=0 + +(d) Delete resource limit: +echo mlx4_0 mr=max qp=max ah=max > /sys/fs/cgroup/rdma/1/rdma.max diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index ff49cf9..b3e0712 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -47,6 +47,8 @@ CONTENTS 5-3. IO 5-3-1. IO Interface Files 5-3-2. Writeback + 5-4. RDMA + 5-4-1. RDMA Interface Files P. Information on Kernel Programming P-1. Filesystem Support for Writeback D. Deprecated v1 Core Features @@ -1088,6 +1090,47 @@ writeback as follows. total available memory and applied the same way as vm.dirty[_background]_ratio. +5-4. RDMA + +The "rdma" controller regulates the distribution of RDMA resources. +This controller implements resource accounting of resources defined +by IB stack. + +5-4-1. RDMA Interface Files + + rdma.max + A readwrite file that exists for all the cgroups except root that + describes current configured resource limit for a RDMA/IB device. + + Lines are keyed by device name and are not ordered. + Each line contains space separated resource name and its configured + limit that can be distributed. + + Following keys are defined. + + uctx Maximum number of User Contexts + pd Maximum number of Protection domains + ah Maximum number of Address handles + mr Maximum number of Memory Regions + mw Maximum number of Memory Windows + cq Maximum number of Completion Queues + srq Maximum number of Shared Receive Queues + qp Maximum number of Queue Pairs + flow Maximum number of Flows + + An example for mlx4 and ocrdma device follows. + + mlx4_0 uctx=max pd=4 ah=2 mr=10 mw=max cq=1 srq=1 qp=10 flow=10 + ocrdma1 uctx=2 pd=2 ah=2 mr=20 mw=max cq=1 srq=1 qp=10 flow=10 + + rdma.current + A read-only file that describes current resource usage. + It exists for all the cgroup except root. + + An example for mlx4 and ocrdma device follows. + + mlx4_1 uctx=1 ah=0 pd=1 cq=4 qp=4 mr=100 srq=0 flow=10 + ocrdma1 uctx=2 pd=2 ah=2 mr=20 mw=max cq=1 srq=1 qp=10 flow=10 P. Information on Kernel Programming