linux-kernel - Re: [PATCH 02/14] x86/sgx: Add /sys/kernel/debug/x86/sgx_total

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Message-ID: <6f3cc681e10877e639b882eaabf1a5e21bd2fc94.camel@kernel.org>
Date:   Thu, 16 Sep 2021 17:09:43 +0300
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Reinette Chatre <reinette.chatre@...el.com>,
        linux-sgx@...r.kernel.org, shuah@...nel.org
Cc:     seanjc@...gle.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 02/14] x86/sgx: Add /sys/kernel/debug/x86/sgx_total_mem

On Wed, 2021-09-15 at 13:30 -0700, Reinette Chatre wrote:
> From: Jarkko Sakkinen <jarkko@...nel.org>
> 
> Just like normal memory, SGX memory can be overcommitted.  SGX has its
> own reclaim mechanism which kicks in when physical SGX memory (Enclave
> Page Cache / EPC) is exhausted.  That reclaim mechanism is relatively
> rarely exercised and needs selftests to poke at it.
> 
> The amount of EPC on the system is determined by the BIOS and it varies
> wildly between systems.  It can be dozens of MB on desktops, or many GB
> on servers.
> 
> To run in a reasonable amount of time, the selftest needs to know how
> much EPC there is in the system.
> 
> Introduce a new debugfs file to export that information.
> 
> Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
> [reinette: Use as placeholder patch until other discussions complete]
> Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>

This could be replaced with the following two patches:

https://lore.kernel.org/linux-sgx/20210914030422.377601-1-jarkko@kernel.org/T/#t

I forgot to CC this to you when I sent it, sorry about that.

/Jarkko