makedumpfile memory usage grows with system memory size

[Atsushi Kumagai]

Hello Michael,

On Mon, 02 Apr 2012 19:15:33 +0200
Michael Holzheu <holzheu at linux.vnet.ibm.com> wrote:

> Hello Ken'ichi,
> 
> On Thu, 2012-03-29 at 17:09 +0900, Ken'ichi Ohmichi wrote:
> > On Wed, 28 Mar 2012 17:22:04 -0400
> > makedumpfile uses the system memory of 2nd-kernel for a bitmap if RHEL.
> > The bitmap represents each page of 1st-kernel is excluded or not.
> > So the bitmap size depends on 1st-kernel's system memory.
> 
> Does this mean that makedumpfile's memory demand linearly grows with 1
> bit per page of 1-st kernel's memory?

Yes, you are right. (Precisely, 2 bit per page.)

> Is that the exact factor, if /tmp is in memory? Or is there any other
> memory allocation that is not constant regarding the 1-st kernel memory
> size?

bitmap file is main cause of memory consuming if 2nd kernel uses initramfs
only. There are other parts where the size of allocated memory varies based
on 1-st kernel memory size, but they don't have big influence.


Thanks
Atsushi Kumagai