From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Yanfei Subject: Re: [PATCH 4/6] x86/mem-hotplug: Support initialize page tables bottom up Date: Tue, 24 Sep 2013 22:07:11 +0800 Message-ID: <52419C8F.4020201@gmail.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130924140545.GA517@mtj.dyndns.org> Sender: linux-doc-owner@vger.kernel.org To: Tejun Heo Cc: Zhang Yanfei , "Rafael J . Wysocki" , lenb@kernel.org, Thomas Gleixner , mingo@elte.hu, "H. Peter Anvin" , Andrew Morton , Toshi Kani , Wanpeng Li , Thomas Renninger , Yinghai Lu , Jiang Liu , Wen Congyang , Lai Jiangshan , isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, Mel Gorman , Minchan Kim , mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, Rik van Riel , jweiner@redhat.com, prarit@redhat.com, "x86@kernel.org" , linux-doc@vger.kernel.org, "linux-kernel@vger.kernel.org" List-Id: linux-acpi@vger.kernel.org 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