From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBBDDC433DB for ; Sat, 13 Mar 2021 16:55:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6F0C64F13 for ; Sat, 13 Mar 2021 16:55:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233977AbhCMQym (ORCPT ); Sat, 13 Mar 2021 11:54:42 -0500 Received: from mga09.intel.com ([134.134.136.24]:64049 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233635AbhCMQym (ORCPT ); Sat, 13 Mar 2021 11:54:42 -0500 IronPort-SDR: XHwBZlFY/Szwfaecu1Fnj9dy6hsWuALE4JNeTMJU8Nrmfr3cLuGNn6aCCzYzPJYZh/ZSxTiH0j hyufNr9HmLUA== X-IronPort-AV: E=McAfee;i="6000,8403,9922"; a="189040915" X-IronPort-AV: E=Sophos;i="5.81,245,1610438400"; d="scan'208";a="189040915" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Mar 2021 08:54:41 -0800 IronPort-SDR: q+dZ4Wdw1KWvvWQuaBlglJ3vdF/LGB5BBKjuN9QbvctfyF6y/4AbdDbUELjkR9dOXXCNvcfIBx p7xtDLTWeL8w== X-IronPort-AV: E=Sophos;i="5.81,245,1610438400"; d="scan'208";a="411366510" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Mar 2021 08:54:41 -0800 Date: Sat, 13 Mar 2021 08:57:01 -0800 From: Jacob Pan To: Tejun Heo Cc: Vipin Sharma , mkoutny@suse.com, rdunlap@infradead.org, thomas.lendacky@amd.com, brijesh.singh@amd.com, jon.grimm@amd.com, eric.vantassell@amd.com, pbonzini@redhat.com, hannes@cmpxchg.org, frankja@linux.ibm.com, borntraeger@de.ibm.com, corbet@lwn.net, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, gingell@google.com, rientjes@google.com, dionnaglaze@google.com, kvm@vger.kernel.org, x86@kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, "Tian, Kevin" , "Liu, Yi L" , "Raj, Ashok" , Alex Williamson , Jason Gunthorpe , Jacob Pan , "jean-philippe@linaro.org" , jacob.jun.pan@intel.com Subject: Re: [RFC v2 2/2] cgroup: sev: Miscellaneous cgroup documentation. Message-ID: <20210313085701.1fd16a39@jacob-builder> In-Reply-To: References: <20210302081705.1990283-1-vipinsh@google.com> <20210302081705.1990283-3-vipinsh@google.com> <20210303185513.27e18fce@jacob-builder> <20210312125821.22d9bfca@jacob-builder> <20210312145904.4071a9d6@jacob-builder> Organization: OTC X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi Tejun, On Sat, 13 Mar 2021 05:20:39 -0500, Tejun Heo wrote: > On Fri, Mar 12, 2021 at 02:59:04PM -0800, Jacob Pan wrote: > > Our primary goal is to limit the amount of IOASIDs that VMs can > > allocate. If a VM is migrated to a different cgroup, I think we need to > > charge/uncharge the destination/source cgroup in order enforce the > > limit. I am not an expert here, any feedback would be appreciated. > > That simply isn't a supported usage model. None of other resources will > get tracked if you do that. Isn't PIDs controller doing the charge/uncharge? I was under the impression that each resource can be independently charged/uncharged, why it affects other resources? Sorry for the basic question. I also didn't quite get the limitation on cgroup v2 migration, this is much simpler than memcg. Could you give me some pointers? BTW, since the IOASIDs are used to tag DMA and bound with guest process(mm) for shared virtual addressing. fork() cannot be supported, so I guess clone is not a solution here. Thanks, Jacob