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From: Tejun Heo <tj@kernel.org>
To: Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
	cgroups@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Shakeel Butt <shakeelb@google.com>,
	Muchun Song <songmuchun@bytedance.com>
Subject: Re: [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory
Date: Thu, 22 Sep 2022 09:08:01 -1000	[thread overview]
Message-ID: <YyyykUJQtYbPVctn@slm.duckdns.org> (raw)
In-Reply-To: <4b8605533e5deade739249bfb341ab9c06d56a1e.camel@linux.intel.com>

Hello,

On Thu, Sep 22, 2022 at 11:59:14AM -0700, Kristen Carlson Accardi wrote:
> Thanks for your question. The SGX EPC memory is a global shared
> resource that can be over committed. The SGX EPC controller should be
> used similarly to the normal memory controller. Normally when there is
> pressure on EPC memory, the reclaimer thread will write out pages from
> EPC memory to a backing RAM that is allocated per enclave. It is
> possible currently for even a single enclave to force all the other
> enclaves to have their epc pages written to backing RAM by allocating
> all the available system EPC memory. This can cause performance issues
> for the enclaves when they have to fault to load pages page in.

Can you please give more concrete examples? I'd love to hear how the SGX EPC
memory is typically used in what amounts and what's the performance
implications when they get reclaimed and so on. ie. Please describe a
realistic usage scenario of contention with sufficient details on how the
system is set up, what the applications are using the SGX EPC memory for and
how much, how the contention on memory affects the users and so on.

Thank you.

-- 
tejun

  reply	other threads:[~2022-09-22 19:08 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 17:10 [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 01/20] x86/sgx: Call cond_resched() at the end of sgx_reclaim_pages() Kristen Carlson Accardi
2022-09-23 12:32   ` Jarkko Sakkinen
2022-09-23 12:35     ` Jarkko Sakkinen
2022-09-23 12:37       ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 02/20] x86/sgx: Store EPC page owner as a 'void *' to handle multiple users Kristen Carlson Accardi
2022-09-22 18:54   ` Dave Hansen
2022-09-23 12:49   ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 03/20] x86/sgx: Track owning enclave in VA EPC pages Kristen Carlson Accardi
2022-09-22 18:55   ` Dave Hansen
2022-09-22 20:04     ` Kristen Carlson Accardi
2022-09-22 21:39       ` Dave Hansen
2022-09-23 12:52   ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 04/20] x86/sgx: Add 'struct sgx_epc_lru' to encapsulate lru list(s) Kristen Carlson Accardi
2022-09-23 13:20   ` Jarkko Sakkinen
2022-09-29 23:04     ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 05/20] x86/sgx: Introduce unreclaimable EPC page lists Kristen Carlson Accardi
2022-09-23 13:29   ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 06/20] x86/sgx: Introduce RECLAIM_IN_PROGRESS flag for EPC pages Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 07/20] x86/sgx: Use a list to track to-be-reclaimed pages during reclaim Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 08/20] x86/sgx: Add EPC page flags to identify type of page Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 09/20] x86/sgx: Allow reclaiming up to 32 pages, but scan 16 by default Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 10/20] x86/sgx: Return the number of EPC pages that were successfully reclaimed Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 11/20] x86/sgx: Add option to ignore age of page during EPC reclaim Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 12/20] x86/sgx: Add helper to retrieve SGX EPC LRU given an EPC page Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 13/20] x86/sgx: Prepare for multiple LRUs Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 14/20] x86/sgx: Expose sgx_reclaim_pages() for use by EPC cgroup Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 15/20] x86/sgx: Add helper to grab pages from an arbitrary EPC LRU Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 16/20] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 17/20] cgroup, x86/sgx: Add SGX EPC cgroup controller Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 18/20] x86/sgx: Enable EPC cgroup controller in SGX core Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 19/20] x86/sgx: Add stats and events interfaces to EPC cgroup controller Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 20/20] docs, cgroup, x86/sgx: Add SGX EPC cgroup controller documentation Kristen Carlson Accardi
2022-09-22 17:41 ` [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory Tejun Heo
2022-09-22 18:59   ` Kristen Carlson Accardi
2022-09-22 19:08     ` Tejun Heo [this message]
2022-09-22 21:03       ` Dave Hansen
2022-09-24  0:09         ` Tejun Heo
2022-09-26 18:30           ` Kristen Carlson Accardi
2022-10-07 16:39           ` Kristen Carlson Accardi
2022-10-07 16:42             ` Tejun Heo
2022-10-07 16:46               ` Kristen Carlson Accardi
2022-09-23 12:24 ` Jarkko Sakkinen

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