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Message-ID: <371249f3-88b6-0bb0-ac69-0cf28f006da0@intel.com>
Date:   Fri, 2 Dec 2022 14:15:27 -0800
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Subject: Re: [PATCH v2 06/18] x86/sgx: Introduce RECLAIM_IN_PROGRESS flag for
 EPC pages
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To:     Kristen Carlson Accardi <kristen@linux.intel.com>,
        jarkko@kernel.org, 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>
Cc:     zhiquan1.li@intel.com, Sean Christopherson <seanjc@google.com>
References: <20221202183655.3767674-1-kristen@linux.intel.com>
 <20221202183655.3767674-7-kristen@linux.intel.com>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <20221202183655.3767674-7-kristen@linux.intel.com>
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On 12/2/22 10:36, Kristen Carlson Accardi wrote:
> When selecting pages to be reclaimed from the page pool (sgx_global_lru),
> the list of reclaimable pages is walked, and any page that is both
> reclaimable and not in the process of being freed is added to a list of
> potential candidates to be reclaimed. After that, this separate list is
> further examined and may or may not ultimately be reclaimed. In order
> to prevent this page from being removed from the sgx_epc_lru_lists
> struct in a separate thread by sgx_drop_epc_page(), keep track of
> whether the EPC page is in the middle of being reclaimed with
> the addtion of a RECLAIM_IN_PROGRESS flag, and do not delete the page
> off the LRU in sgx_drop_epc_page() if it has not yet finished being
> reclaimed.

This never really comes out and tells us what problem is being addressed.