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Message-ID: <d17c270bcbf631736d52b762dad8a6758d7dc951.camel@linux.intel.com>
Subject: Re: [PATCH v2 04/18] x86/sgx: Use sgx_epc_lru_lists for existing
 active page list
From:   Kristen Carlson Accardi <kristen@linux.intel.com>
To:     Dave Hansen <dave.hansen@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>
Date:   Fri, 02 Dec 2022 13:51:10 -0800
In-Reply-To: <ad1bcb0f-661d-a701-2175-c8750d8af8d8@intel.com>
References: <20221202183655.3767674-1-kristen@linux.intel.com>
         <20221202183655.3767674-5-kristen@linux.intel.com>
         <ad1bcb0f-661d-a701-2175-c8750d8af8d8@intel.com>
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On Fri, 2022-12-02 at 13:43 -0800, Dave Hansen wrote:
> On 12/2/22 10:36, Kristen Carlson Accardi wrote:
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0spin_lock(&sgx_global_lru.lo=
ck);
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0for (i =3D 0; i < SGX_N=
R_TO_SCAN; i++) {
> > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0if (list_empty(&sgx_active_page_list))
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0epc_page =3D
> > sgx_epc_pop_reclaimable(&sgx_global_lru);
> > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0if (!epc_page)
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
break;
>=20
> One other nit about the structure of the patches: This introduced
> *both*
> reclaimable and unreclaimable list_heads.=C2=A0 But, it has zero use for
> the
> unreclaimable ones during the refactoring here.=C2=A0 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.

>=20
> BTW, this is a nice sign:
>=20
> > =C2=A0arch/x86/kernel/cpu/sgx/main.c | 39 +++++++++++++++++------------=
-
> > ----
> > =C2=A01 file changed, 19 insertions(+), 20 deletions(-)
>=20
>=20