linux-kernel - Re: [RFC Patch 1/2] kexec: show memory info in /proc/iomem

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Message-ID: <4A8225DB.8040008@redhat.com>
Date:	Wed, 12 Aug 2009 10:15:55 +0800
From:	Amerigo Wang <amwang@...hat.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	linux-kernel@...r.kernel.org, linux-ia64@...r.kernel.org,
	Neil Horman <nhorman@...hat.com>,
	Andi Kleen <andi@...stfloor.org>, akpm@...ux-foundation.org,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [RFC Patch 1/2] kexec: show memory info in /proc/iomem

Eric W. Biederman wrote:
> Amerigo Wang <amwang@...hat.com> writes:
>
>   
>>> Nacked-by: "Eric W. Biederman" <ebiederm@...ssion.com>
>>>
>>> We can inspect the image we are going to load to get this information.
>>> In fact /sbin/kexec already inspects the image we are going to load
>>> to get this information.  Putting this in the kernel adds kernel
>>> complexity for no gain.
>>>   
>>>       
>> /sbin/kexec is supported to know this, of course. But this is not for
>> /sbin/kexec, this is for user (or other programs) to observe the memory
>> information, so that he can know the memory he reserved is too much or not.
>>     
>
>   
>> Without this, it is a little hard to use patch 2/2.
>>     
>
> So add on option to /sbin/kexec.
>   

This can be another choice.
> Furthermore none of this does a good job of predicting how much
> memory /sbin/fsck will require to check the filesystem before we
> write a crash dump.
>   

No one actually knows this without testing... But if 128M on x86 is 
still not enough, that is probably a bug of fsck, not our fault.

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