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

Eric W. Biederman
2009-08-12T02:39:56Z

Amerigo Wang <amwang@redhat.com> writes:

2> Eric W. Biederman wrote:
>> Amerigo Wang <amwang@redhat.com> writes:
>>
>>
>>>> Nacked-by: "Eric W. Biederman" <ebiederm@xmission.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.

x86 covers a very large range of hardware. Some of it nearly as large as
the big ia64 machines. So why would ia64 require significantly more memory
than x86?

Eric