From: Dave Hansen <dave.hansen@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
linux-sgx@vger.kernel.org, kai.svahn@intel.com,
bruce.schlobohm@intel.com
Subject: Re: [PATCH RFC] x86/sgx: Allocate form local NUMA node first
Date: Wed, 24 Jun 2020 17:25:59 -0700 [thread overview]
Message-ID: <59f91e2e-56c2-0395-0ed4-df76a9d7d252@intel.com> (raw)
In-Reply-To: <20200624235406.GH25092@linux.intel.com>
On 6/24/20 4:54 PM, Sean Christopherson wrote:
>> Does this actually work?
>>
>> The node span (->node_start_pfn through start+->node_spanned_pages) only
>> contains pages which the OS is actively managing, usually RAM but
>> sometimes also persistent memory. This has some assumption that the SGX
>> PFNs are within the node's span. I would only _expect_ that to happen
>> if the node was built like this:
>>
>> | Node-X RAM | EPC | Node-X RAM |
>>
>> If the EPC was on either end:
>>
>> | Node-X RAM | EPC |
>> or
>> | EPC | Node-X RAM |
>>
>> I suspect that the pgdat span wouldn't include EPC. EPC is, if I
>> remember correctly, a E820_RESERVED region.
> It is indeed E820_RESERVED, but the BIOS WG for ICX states that EPC regions
> should be enumerated in ACPI SRAT along with regular memory.
>
> But, I haven't actually verified that info makes its way into the kernel's
> pgdata stuff.
Considering this, are we all agreed that this patch is in no condition
to be submitted upstream?
next prev parent reply other threads:[~2020-06-25 0:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 4:39 [PATCH RFC] x86/sgx: Allocate form local NUMA node first Jarkko Sakkinen
2020-06-24 23:12 ` Jarkko Sakkinen
2020-06-24 23:24 ` Dave Hansen
2020-06-24 23:54 ` Sean Christopherson
2020-06-25 0:25 ` Dave Hansen [this message]
2020-06-25 0:57 ` Sean Christopherson
2020-06-25 2:57 ` Jarkko Sakkinen
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