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Date:   Thu, 8 Dec 2022 15:31:40 +0000
From:   Jarkko Sakkinen <jarkko@kernel.org>
To:     Kristen Carlson Accardi <kristen@linux.intel.com>
Cc:     dave.hansen@linux.intel.com, tj@kernel.org,
        linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
        cgroups@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        zhiquan1.li@intel.com, Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH v2 03/18] x86/sgx: Add 'struct sgx_epc_lru_lists' to
 encapsulate lru list(s)
Message-ID: <Y5IDXF+6GmURxbYF@kernel.org>
References: <20221202183655.3767674-1-kristen@linux.intel.com>
 <20221202183655.3767674-4-kristen@linux.intel.com>
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In-Reply-To: <20221202183655.3767674-4-kristen@linux.intel.com>
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On Fri, Dec 02, 2022 at 10:36:39AM -0800, Kristen Carlson Accardi wrote:
> Introduce a data structure to wrap the existing reclaimable list
> and its spinlock in a struct to minimize the code changes needed
> to handle multiple LRUs as well as reclaimable and non-reclaimable
> lists, both of which will be introduced and used by SGX EPC cgroups.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
> Cc: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/kernel/cpu/sgx/sgx.h | 65 +++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
> index 39cb15a8abcb..5e6d88438fae 100644
> --- a/arch/x86/kernel/cpu/sgx/sgx.h
> +++ b/arch/x86/kernel/cpu/sgx/sgx.h
> @@ -90,6 +90,71 @@ static inline void *sgx_get_epc_virt_addr(struct sgx_epc_page *page)
>  	return section->virt_addr + index * PAGE_SIZE;
>  }
>  
> +/*
> + * This data structure wraps a list of reclaimable EPC pages, and a list of
> + * non-reclaimable EPC pages and is used to implement a LRU policy during
> + * reclamation.
> + */
> +struct sgx_epc_lru_lists {
> +	spinlock_t lock;
> +	struct list_head reclaimable;
> +	struct list_head unreclaimable;
> +};
 
Why this is named like this, and not sgx_epc_global_rcu? Are there
any other use cases?

BR, Jarkko