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From: "Haitao Huang" <haitao.huang@linux.intel.com>
To: "hpa@zytor.com" <hpa@zytor.com>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
	"bp@alien8.de" <bp@alien8.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"jarkko@kernel.org" <jarkko@kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"Mehta, Sohil" <sohil.mehta@intel.com>,
	"tj@kernel.org" <tj@kernel.org>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"Huang, Kai" <kai.huang@intel.com>
Cc: "kristen@linux.intel.com" <kristen@linux.intel.com>,
	"yangjie@microsoft.com" <yangjie@microsoft.com>,
	"Li, Zhiquan1" <zhiquan1.li@intel.com>, "Christopherson,,
	Sean" <seanjc@google.com>,
	"mikko.ylinen@linux.intel.com" <mikko.ylinen@linux.intel.com>,
	"Zhang, Bo" <zhanb@microsoft.com>,
	"anakrish@microsoft.com" <anakrish@microsoft.com>
Subject: Re: [PATCH v5 02/18] cgroup/misc: Add SGX EPC resource type and export APIs for SGX driver
Date: Tue, 03 Oct 2023 02:00:04 -0500	[thread overview]
Message-ID: <op.2b78ee0awjvjmi@hhuan26-mobl.amr.corp.intel.com> (raw)
In-Reply-To: <0b24d7ad4de129681a8783f930f48962e572b653.camel@intel.com>

On Wed, 27 Sep 2023 22:59:12 -0500, Huang, Kai <kai.huang@intel.com> wrote:

> On Fri, 2023-09-22 at 20:06 -0700, Haitao Huang wrote:
>> From: Kristen Carlson Accardi <kristen@linux.intel.com>
>>
>> Add SGX EPC memory, MISC_CG_RES_SGX_EPC, to be a valid resource type
>> for the misc controller.
>>
>> Add per resource type private data so that SGX can store additional per
>> cgroup data in misc_cg->misc_cg_res[MISC_CG_RES_SGX_EPC].
>
> To be honest I don't quite understand why putting the above two changes  
> in this
> patch together with exporting misc_cg_root/parent() below.
>
> Any reason why the above two cannot be done together with patch ("  
> x86/sgx:
> Limit process EPC usage with misc cgroup controller"), where these  
> changes are
> actually related?
>
> We all already know that a new EPC misc cgroup will be added.  There's  
> no need
> to actually introduce the new type here only to justify exporting some  
> helper
> functions.
>

I think previous authors intended to separate all prerequisite misc  
changes from SGX changes.
I can combine them if maintainers are fine with it.

>>
>> Export misc_cg_root() so the SGX driver can initialize and add those
>> additional structures to the root misc cgroup as part of initialization
>> for EPC cgroup support. This bootstraps the same additional
>> initialization for non-root cgroups in the 'alloc()' callback added in  
>> the
>> previous patch.
>>
>> The SGX driver, as the EPC memory provider, will have a background
>> worker to reclaim EPC pages to make room for new allocations in the same
>> cgroup when its usage counter reaches near the limit controlled by the
>> cgroup and its ancestors. Therefore it needs to do a walk from the
>> current cgroup up to the root. To enable this walk, move parent_misc()
>> into misc_cgroup.h and make inline to make this function available to
>> SGX, rename it to misc_cg_parent(), and update kernel/cgroup/misc.c to
>> use the new name.
>
> Looks too many details in the above two paragraphs.  Could we have a more
> concise justification for exporting these two functions?
>

This was added to address Jarkko's question, "why does SGX driver need to  
do iterative walks?"
See: https://lore.kernel.org/all/CVHOU5G1SCUT.RCBVZ3W8G2NJ@suppilovahvero/

> And if it were me, I would put it at a relatively later position (e.g.,  
> before
> the patch actually implements EPC cgroup) for better review.  This also  
> applies
> to the first patch.
>

I was told to move all prerequisites to the front or separate out.

https://lore.kernel.org/linux-sgx/CU4H43P3H35X.1BCA3CE4D1250@seitikki/



  reply	other threads:[~2023-10-03  7:02 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-23  3:06 [PATCH v5 00/18] Add Cgroup support for SGX EPC memory Haitao Huang
2023-09-23  3:06 ` [PATCH v5 01/18] cgroup/misc: Add per resource callbacks for CSS events Haitao Huang
2023-09-25 17:09   ` Jarkko Sakkinen
2023-09-26  3:04     ` Haitao Huang
2023-09-26 13:10       ` Jarkko Sakkinen
2023-09-26 13:13         ` Jarkko Sakkinen
2023-09-27  1:56           ` Haitao Huang
2023-10-02 22:47             ` Jarkko Sakkinen
2023-10-02 22:55               ` Jarkko Sakkinen
2023-10-04 15:45                 ` Haitao Huang
2023-10-04 17:18                   ` Tejun Heo
2023-09-27  9:20   ` Huang, Kai
2023-10-03 14:29     ` Haitao Huang
2023-10-17 18:55   ` Michal Koutný
2023-09-23  3:06 ` [PATCH v5 02/18] cgroup/misc: Add SGX EPC resource type and export APIs for SGX driver Haitao Huang
2023-09-25 18:50   ` Tejun Heo
2023-09-28  3:59   ` Huang, Kai
2023-10-03  7:00     ` Haitao Huang [this message]
2023-10-03 19:33       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 03/18] x86/sgx: Add sgx_epc_lru_lists to encapsulate LRU lists Haitao Huang
2023-09-23  3:06 ` [PATCH v5 04/18] x86/sgx: Use sgx_epc_lru_lists for existing active page list Haitao Huang
2023-09-23  3:06 ` [PATCH v5 05/18] x86/sgx: Store reclaimable EPC pages in sgx_epc_lru_lists Haitao Huang
2023-09-27 10:14   ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 06/18] x86/sgx: Introduce EPC page states Haitao Huang
2023-09-25 17:11   ` Jarkko Sakkinen
2023-09-27 10:28   ` Huang, Kai
2023-10-03  4:49     ` Haitao Huang
2023-10-03 20:03       ` Huang, Kai
2023-10-04 15:24         ` Haitao Huang
2023-10-04 21:05           ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 07/18] x86/sgx: Introduce RECLAIM_IN_PROGRESS state Haitao Huang
2023-09-25 17:13   ` Jarkko Sakkinen
2023-09-27 10:42   ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 08/18] x86/sgx: Use a list to track to-be-reclaimed pages Haitao Huang
2023-09-28  9:28   ` Huang, Kai
2023-10-03  5:09     ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 09/18] x86/sgx: Store struct sgx_encl when allocating new VA pages Haitao Huang
2023-09-27 11:14   ` Huang, Kai
2023-09-27 15:35     ` Haitao Huang
2023-09-27 21:21       ` Huang, Kai
2023-09-29 15:06         ` Haitao Huang
2023-10-02 11:05           ` Huang, Kai
2023-09-27 11:35   ` Huang, Kai
2023-10-03  6:45     ` Haitao Huang
2023-10-03 20:07       ` Huang, Kai
2023-10-04 15:03         ` Haitao Huang
2023-10-04 21:13           ` Huang, Kai
2023-10-05  4:22             ` Haitao Huang
2023-10-05  6:49               ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 10/18] x86/sgx: Add EPC page flags to identify owner types Haitao Huang
2023-09-23  3:06 ` [PATCH v5 11/18] x86/sgx: store unreclaimable pages in LRU lists Haitao Huang
2023-09-27 11:57   ` Huang, Kai
2023-10-03  5:42     ` Haitao Huang
2023-09-28  9:41   ` Huang, Kai
2023-10-03  5:15     ` Haitao Huang
2023-10-03 20:12       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 12/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Haitao Huang
2023-10-09 23:45   ` Huang, Kai
2023-10-10  0:23     ` Sean Christopherson
2023-10-10  0:50       ` Huang, Kai
2023-10-10  1:34         ` Huang, Kai
2023-10-10 16:49           ` Haitao Huang
2023-10-11  0:51             ` Huang, Kai
2023-10-12 13:27               ` Haitao Huang
2023-10-16 10:57                 ` Huang, Kai
2023-10-16 19:52                   ` Haitao Huang
2023-10-16 21:09                     ` Huang, Kai
2023-10-17  0:10                       ` Haitao Huang
2023-10-17  1:34                         ` Huang, Kai
2023-10-17 12:58                           ` Haitao Huang
2023-10-17 18:54                             ` Michal Koutný
2023-10-17 19:13                               ` Michal Koutný
2023-10-18  4:39                                 ` Haitao Huang
2023-10-18  4:37                               ` Haitao Huang
2023-10-18 13:55                                 ` Dave Hansen
2023-10-18 15:26                                   ` Haitao Huang
2023-10-18 15:37                                     ` Dave Hansen
2023-10-18 15:52                                       ` Michal Koutný
2023-10-18 16:25                                         ` Haitao Huang
2023-10-16 21:32                     ` Sean Christopherson
2023-10-17  0:09                       ` Haitao Huang
2023-10-17 15:43                         ` Sean Christopherson
2023-10-17 11:49                       ` Mikko Ylinen
2023-10-11  1:14             ` Huang, Kai
2023-10-16 11:02               ` Huang, Kai
2023-10-10  1:42       ` Haitao Huang
2023-10-10  2:23         ` Huang, Kai
2023-10-10 13:26           ` Haitao Huang
2023-10-11  0:01             ` Sean Christopherson
2023-10-11 15:02               ` Haitao Huang
2023-10-10  1:04     ` Haitao Huang
2023-10-10  1:18       ` Huang, Kai
2023-10-10  1:38         ` Haitao Huang
2023-10-10  2:12           ` Huang, Kai
2023-10-10 17:05             ` Haitao Huang
2023-10-11  0:31               ` Huang, Kai
2023-10-11 16:04                 ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 13/18] x86/sgx: Expose sgx_reclaim_pages() for use by EPC cgroup Haitao Huang
2023-10-05 12:24   ` Huang, Kai
2023-10-05 19:23     ` Haitao Huang
2023-10-05 20:25       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 14/18] x86/sgx: Add helper to grab pages from an arbitrary EPC LRU Haitao Huang
2023-09-23  3:06 ` [PATCH v5 15/18] x86/sgx: Prepare for multiple LRUs Haitao Huang
2023-10-05 12:30   ` Huang, Kai
2023-10-05 19:33     ` Haitao Huang
2023-10-05 20:38       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 16/18] x86/sgx: Limit process EPC usage with misc cgroup controller Haitao Huang
2023-09-25 17:15   ` Jarkko Sakkinen
2023-10-05 21:01   ` Huang, Kai
2023-10-10  0:12   ` Huang, Kai
2023-10-10  0:16   ` Huang, Kai
2023-10-10  0:26   ` Huang, Kai
2023-10-22 18:26     ` Haitao Huang
2023-10-10  9:19   ` Huang, Kai
2023-10-10  9:32   ` Huang, Kai
2023-10-17 18:54   ` Michal Koutný
2023-10-19 16:05     ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 17/18] Docs/x86/sgx: Add description for cgroup support Haitao Huang
2023-09-23  3:06 ` [PATCH v5 18/18] selftests/sgx: Add scripts for EPC cgroup testing Haitao Huang

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