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Date: Tue, 1 Feb 2011 15:19:50 +0800
From: =?utf-8?Q?Am=C3=A9rico?= Wang <xiyou.wangcong@gmail.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: kosaki.motohiro@jp.fujitsu.com,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        linux kernel mailing list <linux-kernel@vger.kernel.org>,
        Jarod Wilson <jwilson@redhat.com>
Subject: Re: Query about kdump_msg hook into crash_kexec()
Message-ID: <20110201071933.GA21239@cr0.nay.redhat.com>
References: <20110131225939.GH11974@redhat.com>
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On Mon, Jan 31, 2011 at 05:59:39PM -0500, Vivek Goyal wrote:
>
>Anyway, if an image is loaded and we have setup to capture dump also
>why do we need to save kmsg with the help of an helper. I am assuming
>this is more of a debugging aid if we have no other way to capture the
>kernel log buffer. So if somebody has setup kdump to capture the
>vmcore, why to call another handler which tries to save part of the
>vmcore (kmsg) separately.
>

Well, kmsg dumper is not only for panic/oops, it can also save kernel
messages when the system is reboot/halt.

Yeah, it is true that vmcore contains log_buf, but I think the users
of ramoops/mtdoops are mainly those who don't have kdump configured
in their kernels, they are cheaper than kdump, but less powerful.

Thanks.
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