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

From: Maxim Uvarov <muvarov@gmail.com>
To: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: riel@redhat.com, kexec@lists.infradead.org, hughd@google.com,
	linux-kernel@vger.kernel.org, lisa.mitchell@hp.com,
	vgoyal@redhat.com, linux-mm@kvack.org, d.hatayama@jp.fujitsu.com,
	zhangyanfei@cn.fujitsu.com, ebiederm@xmission.com,
	kosaki.motohiro@jp.fujitsu.com, akpm@linux-foundation.org,
	walken@google.com, cpw@sgi.com, jingbai.ma@hp.com
Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore
Date: Fri, 28 Jun 2013 20:40:14 +0400	[thread overview]
Message-ID: <CAJGZr0+9VUweN1Ssdq6P9Lug1GnTB3+RPv77JLRmnw=rpd9+Dw@mail.gmail.com> (raw)
In-Reply-To: <20130603174351.d04b2ac71d1bab0df242e0ba@mxc.nes.nec.co.jp>

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Did test on 1TB machine. Total vmcore capture and save took 143 minutes
while vmcore size increased from 9Gb to 59Gb.

Will do some debug for that.

Maxim.

2013/6/3 Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>

> Hello Maxim,
>
> On Thu, 30 May 2013 14:30:01 +0400
> Maxim Uvarov <muvarov@gmail.com> wrote:
>
> > 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?
>
> You can fetch them from here, "mmap" branch is the change:
>
>   git://git.code.sf.net/p/makedumpfile/code
>
> And they will be merged into v1.5.4.
>
>
> Thanks
> Atsushi Kumagai
>
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>

-- 
Best regards,
Maxim Uvarov

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