linux-kernel - Re: [PATCH v2 04/18] x86/sgx: Use sgx_epc_lru

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Date:   Fri, 02 Dec 2022 13:51:10 -0800
From:   Kristen Carlson Accardi <kristen@...ux.intel.com>
To:     Dave Hansen <dave.hansen@...el.com>, jarkko@...nel.org,
        dave.hansen@...ux.intel.com, tj@...nel.org,
        linux-kernel@...r.kernel.org, linux-sgx@...r.kernel.org,
        cgroups@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Cc:     zhiquan1.li@...el.com, Sean Christopherson <seanjc@...gle.com>
Subject: Re: [PATCH v2 04/18] x86/sgx: Use sgx_epc_lru_lists for existing
 active page list

On Fri, 2022-12-02 at 13:43 -0800, Dave Hansen wrote:
> On 12/2/22 10:36, Kristen Carlson Accardi wrote:
> > +       spin_lock(&sgx_global_lru.lock);
> >         for (i = 0; i < SGX_NR_TO_SCAN; i++) {
> > -               if (list_empty(&sgx_active_page_list))
> > +               epc_page =
> > sgx_epc_pop_reclaimable(&sgx_global_lru);
> > +               if (!epc_page)
> >                         break;
> 
> One other nit about the structure of the patches: This introduced
> *both*
> reclaimable and unreclaimable list_heads.  But, it has zero use for
> the
> unreclaimable ones during the refactoring here.  I probably would
> have
> left out the 'unreclaimable' bits for now.

I know - and originally the addition of unreclaimable was added later,
but when I posted the RFC I felt there was some misunderstanding about
what this data structure was and how it would be used because the
addition of the unreclaimable bits came later. So I stuck both lists in
one so it'd be a better view of what the data structure would look
like.

> 
> BTW, this is a nice sign:
> 
> >  arch/x86/kernel/cpu/sgx/main.c | 39 +++++++++++++++++-------------
> > ----
> >  1 file changed, 19 insertions(+), 20 deletions(-)
> 
>