From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx119.postini.com [74.125.245.119]) by kanga.kvack.org (Postfix) with SMTP id 9CF946B0034 for ; Thu, 30 May 2013 05:14:08 -0400 (EDT) Received: by mail-ob0-f171.google.com with SMTP id dn14so6176obc.16 for ; Thu, 30 May 2013 02:14:07 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <51A2BBA7.50607@jp.fujitsu.com> References: <20130523052421.13864.83978.stgit@localhost6.localdomain6> <20130523052547.13864.83306.stgit@localhost6.localdomain6> <20130523152445.17549682ae45b5aab3f3cde0@linux-foundation.org> <51A2BBA7.50607@jp.fujitsu.com> Date: Thu, 30 May 2013 13:14:07 +0400 Message-ID: Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore From: Maxim Uvarov Content-Type: multipart/alternative; boundary=001a11c238a8a96d1204ddebebd7 Sender: owner-linux-mm@kvack.org List-ID: To: HATAYAMA Daisuke Cc: Andrew Morton , riel@redhat.com, hughd@google.com, jingbai.ma@hp.com, "kexec@lists.infradead.org" , linux-kernel@vger.kernel.org, lisa.mitchell@hp.com, linux-mm@kvack.org, Atsushi Kumagai , "Eric W. Biederman" , kosaki.motohiro@jp.fujitsu.com, zhangyanfei@cn.fujitsu.com, walken@google.com, Cliff Wickman , Vivek Goyal --001a11c238a8a96d1204ddebebd7 Content-Type: text/plain; charset=ISO-8859-1 2013/5/27 HATAYAMA Daisuke > (2013/05/24 18:02), Maxim Uvarov wrote: > >> >> >> >> 2013/5/24 Andrew Morton > akpm@linux-foundation.**org >> >> >> >> On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke < >> d.hatayama@jp.fujitsu.com >> >> wrote: >> >> > This patch introduces mmap_vmcore(). >> > >> > Don't permit writable nor executable mapping even with mprotect() >> > because this mmap() is aimed at reading crash dump memory. >> > Non-writable mapping is also requirement of remap_pfn_range() when >> > mapping linear pages on non-consecutive physical pages; see >> > is_cow_mapping(). >> > >> > Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by >> > remap_vmalloc_range_pertial at the same time for a single >> > vma. do_munmap() can correctly clean partially remapped vma with >> two >> > functions in abnormal case. See zap_pte_range(), vm_normal_page() >> and >> > their comments for details. >> > >> > On x86-32 PAE kernels, mmap() supports at most 16TB memory only. >> This >> > limitation comes from the fact that the third argument of >> > remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned >> long. >> >> More reviewing and testing, please. >> >> >> Do you have git pull for both kernel and userland changes? I would like >> to do some more testing on my machines. >> >> Maxim. >> > > Thanks! That's very helpful. > > -- > Thanks. > HATAYAMA, Daisuke > > Any update for this? Where can I checkout all sources? -- Best regards, Maxim Uvarov --001a11c238a8a96d1204ddebebd7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



2013/5/27 HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com&= gt;
(2013/05/24 18:02), Maxim Uvarov wrote:



2013/5/24 Andrew Morton <akpm@linux-foundation.org <mailto:akpm@linux-foundation.o= rg>>


=A0 =A0 On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke <d.hatayama@jp.fujitsu.c= om <mailto:d.hatayama@jp.fujitsu.com>> wrote:

=A0 =A0 =A0> This patch introduces mmap_vmcore().
=A0 =A0 =A0>
=A0 =A0 =A0> Don't permit writable nor executable mapping even with = mprotect()
=A0 =A0 =A0> because this mmap() is aimed at reading crash dump memory.<= br> =A0 =A0 =A0> Non-writable mapping is also requirement of remap_pfn_range= () when
=A0 =A0 =A0> mapping linear pages on non-consecutive physical pages; see=
=A0 =A0 =A0> is_cow_mapping().
=A0 =A0 =A0>
=A0 =A0 =A0> Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and= by
=A0 =A0 =A0> remap_vmalloc_range_pertial at the same time for a single =A0 =A0 =A0> vma. do_munmap() can correctly clean partially remapped vma= with two
=A0 =A0 =A0> functions in abnormal case. See zap_pte_range(), vm_normal_= page() and
=A0 =A0 =A0> their comments for details.
=A0 =A0 =A0>
=A0 =A0 =A0> On x86-32 PAE kernels, mmap() supports at most 16TB memory = only. This
=A0 =A0 =A0> limitation comes from the fact that the third argument of =A0 =A0 =A0> remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsi= gned long.

=A0 =A0 More reviewing and testing, please.


Do you have git pull for both kernel and userland changes? I would like to = do some more testing on my machines.

Maxim.

Thanks! That's very helpful.

--
Thanks.
HATAYAMA, Daisuke

Any update for this? Where can I checkout = all sources?

--
Best regards,<= br>Maxim Uvarov
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