Date: Mon, 29 Apr 2013 15:36:12 -0400
From: Vivek Goyal <vgoyal@redhat.com>
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: ebiederm@xmission.com, akpm@linux-foundation.org, cpw@sgi.com,
        kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com,
        kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
        zhangyanfei@cn.fujitsu.com, jingbai.ma@hp.com
Subject: Re: [PATCH v4 5/8] vmcore: copy ELF note segments in the 2nd kernel
 per page vmcore objects
Message-ID: <20130429193611.GQ8204@redhat.com>
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On Sat, Apr 13, 2013 at 09:21:33AM +0900, HATAYAMA Daisuke wrote:

[..]
> ELF notes are per-cpu, so total size of ELF note segments increases
> according to the number of CPUs. The current maximum number of CPUs on
> x86_64 is 5192, and there's already system with 4192 CPUs in SGI,
> where total size amounts to 1MB. This can be larger in the neare
> futrue or possibly even now on another architecture. Thus, to avoid
> the case where memory allocation for large block fails, we allocate
> vmcore objects per pages.

IIRC, eric had suggested using vmalloc() and remap_vmalloc_range(). What's
wrong with that? That should keep your vc_list relatively smaller.

Thanks
Vivek
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