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From: Vivek Goyal <vgoyal@redhat.com>
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: ebiederm@xmission.com, cpw@sgi.com,
	kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/13] vmcore: copy ELF note segments in buffer on 2nd kernel
Date: Tue, 19 Feb 2013 18:05:42 -0500	[thread overview]
Message-ID: <20130219230542.GF6039@redhat.com> (raw)
In-Reply-To: <20130219.020234.255275278.d.hatayama@jp.fujitsu.com>

On Tue, Feb 19, 2013 at 02:02:34AM +0900, HATAYAMA Daisuke wrote:

[..]
> Anyway, what I'll do in the next version, are in summary:
> 
> - append pad notes in each notes on the 1st kernel in every
>   architectures, and
> - check if each note is in page-size boundary, and if not so, copy it
>   in the 2nd kernel and then append pad notes to it.

Makes sense to me. Most of the time first kernel and second kernel are
same so no copying of notes will take place. Only in corner cases of
older kernel being used as first kernel, copying will take place.

One other possibility is that deny mmap() if first kernel did not
prepare notes on page size boundary.

Thanks
Vivek

WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	lisa.mitchell@hp.com, kumagai-atsushi@mxc.nes.nec.co.jp,
	ebiederm@xmission.com, cpw@sgi.com
Subject: Re: [PATCH 09/13] vmcore: copy ELF note segments in buffer on 2nd kernel
Date: Tue, 19 Feb 2013 18:05:42 -0500	[thread overview]
Message-ID: <20130219230542.GF6039@redhat.com> (raw)
In-Reply-To: <20130219.020234.255275278.d.hatayama@jp.fujitsu.com>

On Tue, Feb 19, 2013 at 02:02:34AM +0900, HATAYAMA Daisuke wrote:

[..]
> Anyway, what I'll do in the next version, are in summary:
> 
> - append pad notes in each notes on the 1st kernel in every
>   architectures, and
> - check if each note is in page-size boundary, and if not so, copy it
>   in the 2nd kernel and then append pad notes to it.

Makes sense to me. Most of the time first kernel and second kernel are
same so no copying of notes will take place. Only in corner cases of
older kernel being used as first kernel, copying will take place.

One other possibility is that deny mmap() if first kernel did not
prepare notes on page size boundary.

Thanks
Vivek

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  reply	other threads:[~2013-02-19 23:05 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-14 10:11 [PATCH 00/13] kdump, vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-02-14 10:11 ` HATAYAMA Daisuke
2013-02-14 10:11 ` [PATCH 01/13] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-02-14 10:11   ` HATAYAMA Daisuke
2013-02-15 15:01   ` Vivek Goyal
2013-02-15 15:01     ` Vivek Goyal
2013-02-14 10:11 ` [PATCH 02/13] vmcore: round up buffer size of ELF headers by PAGE_SIZE HATAYAMA Daisuke
2013-02-14 10:11   ` HATAYAMA Daisuke
2013-02-15 15:18   ` Vivek Goyal
2013-02-15 15:18     ` Vivek Goyal
2013-02-18 15:58     ` HATAYAMA Daisuke
2013-02-18 15:58       ` HATAYAMA Daisuke
2013-02-14 10:11 ` [PATCH 03/13] vmcore: fill unused part of buffer for ELF headers with 0 HATAYAMA Daisuke
2013-02-14 10:11   ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 04/13] vmcore: introduce types for objects copied in 2nd kernel HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 15:28   ` Vivek Goyal
2013-02-15 15:28     ` Vivek Goyal
2013-02-18 16:06     ` HATAYAMA Daisuke
2013-02-18 16:06       ` HATAYAMA Daisuke
2013-02-19 23:07       ` Vivek Goyal
2013-02-19 23:07         ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 05/13] vmcore: modify ELF32 code according to new type HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 15:30   ` Vivek Goyal
2013-02-15 15:30     ` Vivek Goyal
2013-02-18 16:11     ` HATAYAMA Daisuke
2013-02-18 16:11       ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 06/13] vmcore: modify vmcore clean-up function to free buffer on 2nd kernel HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 15:32   ` Vivek Goyal
2013-02-15 15:32     ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 07/13] vmcore: modify read_vmcore() to read " HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 15:51   ` Vivek Goyal
2013-02-15 15:51     ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 08/13] vmcore: remove unused helper function HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 15:52   ` Vivek Goyal
2013-02-15 15:52     ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 09/13] vmcore: copy ELF note segments in buffer on 2nd kernel HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15 16:53   ` Vivek Goyal
2013-02-15 16:53     ` Vivek Goyal
2013-02-18 17:02     ` HATAYAMA Daisuke
2013-02-18 17:02       ` HATAYAMA Daisuke
2013-02-19 23:05       ` Vivek Goyal [this message]
2013-02-19 23:05         ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 10/13] vmcore: round-up offset of vmcore object in page-size boundary HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 11/13] vmcore: count holes generated by round-up operation for vmcore size HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 12/13] vmcore: copy non page-size aligned head and tail pages in 2nd kernel HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 13/13] vmcore: introduce mmap_vmcore() HATAYAMA Daisuke
2013-02-14 10:12   ` HATAYAMA Daisuke
2013-02-15  3:57 ` [PATCH 00/13] kdump, vmcore: support mmap() on /proc/vmcore Atsushi Kumagai
2013-02-15  3:57   ` Atsushi Kumagai
2013-02-18  0:16   ` Hatayama, Daisuke
2013-02-18  0:16     ` Hatayama, Daisuke
2013-03-27  5:51 ` makedumpfile mmap() benchmark Jingbai Ma
2013-03-27  5:51   ` Jingbai Ma
2013-03-27  6:23   ` HATAYAMA Daisuke
2013-03-27  6:23     ` HATAYAMA Daisuke
2013-03-27  6:35     ` Jingbai Ma
2013-03-27  6:35       ` Jingbai Ma

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