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Fri Nov 6 13:01:15 EST 2009


changes.  Once it is confirmed there is a solution with the 64bit
kernel we just need a small patch to boot.txt and a few tweaks to 
/sbin/kexec to handle a 64bit bzImage.

>> I don't buy the argument that there is a direct connection between
>> the amount of memory you have and how much memory it takes to dump it.
>> Even an indirect connections seems suspicious.
>
> Memory requirement by user space might be of interest though like dump
> filtering tools. I vaguely remember that it used to first traverse all
> the memory pages, create some internal data structures and then start
> dumping.
>
> So memory required by filtering tool might be directly proportional to
> amount of memory present in the system.

Assuming your dump filtering tool creates a bitmap of pages to be dumped
you get a ration of 32K to 1.  Or 3MB for 100GB and 32MB for 1TB.
Which is noticeable in the worst case but definitely not enough to push
us past 2GB.

> Vitaly, have you really run into cases where 2G upper limit is a concern.
> What is the configuration you have, how much memory it has and how much
> memory are you planning to reserve for kdump kernel?

A good question.

Eric



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