Message-ID: <52419C8F.4020201@gmail.com>
Date: Tue, 24 Sep 2013 22:07:11 +0800
From: Zhang Yanfei <zhangyanfei.yes@gmail.com>
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To: Tejun Heo <tj@kernel.org>
CC: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
        "Rafael J . Wysocki" <rjw@sisk.pl>, lenb@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>, mingo@elte.hu,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Toshi Kani <toshi.kani@hp.com>, Wanpeng Li <liwanp@linux.vnet.ibm.com>,
        Thomas Renninger <trenn@suse.de>, Yinghai Lu <yinghai@kernel.org>,
        Jiang Liu <jiang.liu@huawei.com>, Wen Congyang <wency@cn.fujitsu.com>,
        Lai Jiangshan <laijs@cn.fujitsu.com>, isimatu.yasuaki@jp.fujitsu.com,
        izumi.taku@jp.fujitsu.com, Mel Gorman <mgorman@suse.de>,
        Minchan Kim <minchan@kernel.org>, mina86@mina86.com,
        gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com,
        lwoodman@redhat.com, Rik van Riel <riel@redhat.com>,
        jweiner@redhat.com, prarit@redhat.com,
        "x86@kernel.org" <x86@kernel.org>, linux-doc@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>, linux-acpi@vger.kernel.org,
        imtangchen@gmail.com
Subject: Re: [PATCH 4/6] x86/mem-hotplug: Support initialize page tables bottom
 up
References: <524162DA.30004@cn.fujitsu.com> <5241649B.3090302@cn.fujitsu.com> <20130924123340.GE2366@htj.dyndns.org> <52419264.3020409@gmail.com> <20130924132727.GI2366@htj.dyndns.org> <524194F6.4000101@gmail.com> <20130924133908.GJ2366@htj.dyndns.org> <5241996B.5080701@gmail.com> <20130924140545.GA517@mtj.dyndns.org>
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On 09/24/2013 10:05 PM, Tejun Heo wrote:
> On Tue, Sep 24, 2013 at 09:53:47PM +0800, Zhang Yanfei wrote:
>> OK, this is just because we allocate pagtables just above the kernel.
>> And if we use up the BRK space that is reserved for inital pagetables,
>> we will use memblock to allocate memory for pagetables, and the memory
>> allocated here should be mapped already. So we first map [kernel_end, end)
>> to make memory above the kernel be mapped as soon as possible. And then
>> use pagetables allocated above the kernel to map [ISA_END_ADDRESS, kernel_end).
> 
> I see.  The code seems fine to me then.  Can you please add comment
> explaining why the split calls are necessary?

Okay, will add the comment.

Thanks.

-- 
Thanks.
Zhang Yanfei
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