Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore

From: Maxim Uvarov <muvarov@gmail.com>
To: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	riel@redhat.com, hughd@google.com, jingbai.ma@hp.com,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	linux-kernel@vger.kernel.org, lisa.mitchell@hp.com,
	linux-mm@kvack.org,
	Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	kosaki.motohiro@jp.fujitsu.com, walken@google.com,
	Cliff Wickman <cpw@sgi.com>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore
Date: Thu, 30 May 2013 14:30:01 +0400	[thread overview]
Message-ID: <CAJGZr0Ld6Q4a4f-VObAbvqCp=+fTFNEc6M-Fdnhh28GTcSm1=w@mail.gmail.com> (raw)
In-Reply-To: <51A71B49.3070003@cn.fujitsu.com>

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2013/5/30 Zhang Yanfei <zhangyanfei@cn.fujitsu.com>

> On 05/30/2013 05:14 PM, Maxim Uvarov wrote:
> >
> >
> >
> > 2013/5/27 HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com <mailto:
> d.hatayama@jp.fujitsu.com>>
> >
> >     (2013/05/24 18:02), Maxim Uvarov wrote:
> >
> >
> >
> >
> >         2013/5/24 Andrew Morton <akpm@linux-foundation.org <mailto:
> akpm@linux-foundation.org> <mailto:akpm@linux-foundation.__org <mailto:
> akpm@linux-foundation.org>>>
> >
> >
> >             On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke <
> d.hatayama@jp.fujitsu.com <mailto:d.hatayama@jp.fujitsu.com> <mailto:
> d.hatayama@jp.fujitsu.__com <mailto: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

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