From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id F32466B0032 for ; Thu, 30 May 2013 06:30:02 -0400 (EDT) Received: by mail-ob0-f172.google.com with SMTP id wo10so147522obc.17 for ; Thu, 30 May 2013 03:30:02 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <51A71B49.3070003@cn.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> <51A71B49.3070003@cn.fujitsu.com> Date: Thu, 30 May 2013 14:30:01 +0400 Message-ID: Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore From: Maxim Uvarov Content-Type: multipart/alternative; boundary=001a11c2fbd0208b6404ddecfb4e Sender: owner-linux-mm@kvack.org List-ID: To: Zhang Yanfei Cc: HATAYAMA Daisuke , 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, walken@google.com, Cliff Wickman , Vivek Goyal --001a11c2fbd0208b6404ddecfb4e Content-Type: text/plain; charset=ISO-8859-1 2013/5/30 Zhang Yanfei > On 05/30/2013 05:14 PM, Maxim Uvarov wrote: > > > > > > > > 2013/5/27 HATAYAMA Daisuke d.hatayama@jp.fujitsu.com>> > > > > (2013/05/24 18:02), Maxim Uvarov wrote: > > > > > > > > > > 2013/5/24 Andrew Morton akpm@linux-foundation.org> akpm@linux-foundation.org>>> > > > > > > On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke < > d.hatayama@jp.fujitsu.com 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? > > This series is now in Andrew Morton's -mm tree. > > Ok, and what about makedumpfile changes? Is it possible to fetch them from somewhere? > -- > Thanks. > Zhang Yanfei > -- Best regards, Maxim Uvarov --001a11c2fbd0208b6404ddecfb4e Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



2013/5/30 Zhang Yanfei <zhangyanfei@cn.fujitsu.com>= ;
On 05/30/2013 05:14 PM, Maxim Uvarov wrote:<= br> >
>
>
> 2013/5/27 HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com <mailto:d.hatayama@jp.fujitsu.com>>
>
> =A0 =A0 (2013/05/24 18:02), Maxim Uvarov wrote:
>
>
>
>
> =A0 =A0 =A0 =A0 2013/5/24 Andrew Morton <akpm@linux-foundation.org <mailto:akpm@linux-foundation.org> <= ;mailto:akpm@linux-foundation.__org <mailto:akpm@linux-f= oundation.org>>>
>
>
> =A0 =A0 =A0 =A0 =A0 =A0 On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Da= isuke <d.hatayama@jp.fujits= u.com <mailto:d.hatayam= a@jp.fujitsu.com> <mailto:d.hatayama@jp.fujitsu.__com <mailto:d.hatayama@jp.fujitsu.com>>> wrote:
>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> This patch introduces mmap_vmcore(). > =A0 =A0 =A0 =A0 =A0 =A0 =A0>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> Don't permit writable nor executab= le mapping even with mprotect()
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> because this mmap() is aimed at readin= g crash dump memory.
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> Non-writable mapping is also requireme= nt of remap_pfn_range() when
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> mapping linear pages on non-consecutiv= e physical pages; see
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> is_cow_mapping().
> =A0 =A0 =A0 =A0 =A0 =A0 =A0>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> Set VM_MIXEDMAP flag to remap memory b= y remap_pfn_range and by
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> remap_vmalloc_range_pertial at the sam= e time for a single
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> vma. do_munmap() can correctly clean p= artially remapped vma with two
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> functions in abnormal case. See zap_pt= e_range(), vm_normal_page() and
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> their comments for details.
> =A0 =A0 =A0 =A0 =A0 =A0 =A0>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> On x86-32 PAE kernels, mmap() supports= at most 16TB memory only. This
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> limitation comes from the fact that th= e third argument of
> =A0 =A0 =A0 =A0 =A0 =A0 =A0> remap_pfn_range(), pfn, is of 32-bit l= ength on x86-32: unsigned long.
>
> =A0 =A0 =A0 =A0 =A0 =A0 More reviewing and testing, please.
>
>
> =A0 =A0 =A0 =A0 Do you have git pull for both kernel and userland chan= ges? I would like to do some more testing on my machines.
>
> =A0 =A0 =A0 =A0 Maxim.
>
>
> =A0 =A0 Thanks! That's very helpful.
>
> =A0 =A0 --
> =A0 =A0 Thanks.
> =A0 =A0 HATAYAMA, Daisuke
>
> Any update for this? Where can I checkout all sources?

This series is now in Andrew Morton's -mm tree.

Ok, and what about makedumpfile changes? Is it possible to fetch th= em from somewhere?
=A0
--
Thanks.
Zhang Yanfei



--
Best rega= rds,
Maxim Uvarov
--001a11c2fbd0208b6404ddecfb4e-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org