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Date:   Fri, 21 Oct 2022 02:52:09 +0000
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From:   "Yajun Deng" <yajun.deng@linux.dev>
Message-ID: <12e1236e3200c03b7fb2771cf7f8f72a@linux.dev>
Subject: Re: [PATCH] x86/e820: make e820 type string uniform
To:     "Dave Hansen" <dave.hansen@intel.com>, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        hpa@zytor.com
Cc:     noodles@fb.com, ross.philipson@oracle.com, daniel.kiper@oracle.com,
        x86@kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <8f84e984-c42b-b672-c9db-e7d4464b2a15@intel.com>
References: <8f84e984-c42b-b672-c9db-e7d4464b2a15@intel.com>
 <20221020115609.223940-1-yajun.deng@linux.dev>
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October 20, 2022 11:44 PM, "Dave Hansen" <dave.hansen@intel.com> wrote:=
=0A=0A> On 10/20/22 04:56, Yajun Deng wrote:=0A> =0A>> /proc/iomem:=0A>> =
...=0A>> 00000000-00000fff : Reserved=0A>> 00001000-0005efff : System RAM=
=0A>> 0005f000-0005ffff : Reserved=0A>> 00060000-0009ffff : System RAM=0A=
>> 000a0000-000fffff : Reserved=0A>> 000a0000-000bffff : PCI Bus 0000:00=
=0A>> 000c0000-000cddff : Video ROM=0A>> 000f0000-000fffff : System ROM=
=0A>> 00100000-80ff3017 : System RAM=0A>> 80ff3018-81003e57 : System RAM =
(kernel)=0A>> 81003e58-81004017 : System RAM=0A>> 81004018-81023c57 : Sys=
tem RAM (kernel)=0A>> 81023c58-87672fff : System RAM=0A> =0A> I guess thi=
s is a pretty minimal change. It definitely makes=0A> /proc/iomem more hu=
man-readable.=0A> =0A> Did you consider if this change might break any us=
ers of this file?=0A=0AYes, it may be.=0AI don't know how many users use =
this file, but I think the impact of this change is limited.=0A=0A1st: Th=
is is not the first time this file has been changed. In commit =0A     ad=
5fb870c486("e820, efi: add ACPI 6.0 persistent memory types"), the E820_P=
RAM changed =0A     from "Persistent RAM" to "Persistent Memory (legacy)"=
.=0A=0A2nd: only super users can access the full information from /proc/i=
omem, which means the users=0A     of this file are limited.=0A     In co=
mmit 51d7b120418e("/proc/iomem: only expose physical resource addresses t=
o privileged users")=0A=0A3rd: The E820_TYPE_RESERVED_KERN changed from "=
System RAM" to "System RAM (kernel)" is a minimal change,=0A     and it a=
lso contains the "System RAM" string.