makedumpfile memory usage grows with system memory size

[tachibana at mxm.nes.nec.co.jp]

Hi Don,

On 2012/03/30 09:19:16 -0400, Don Zickus <dzickus at redhat.com> wrote:
> On Fri, Mar 30, 2012 at 06:43:34PM +0900, Atsushi Kumagai wrote:
> > Hello Don,
> > Does setting TMPDIR solve your problem ? Please refer to the man page.
> > 
> > 
> >     ENVIRONMENT VARIABLES
> >            TMPDIR  This  environment  variable  is  for  a temporary memory bitmap
> >                    file.  If your machine has a lots of memory and you  use  tmpfs
> >                    on  /tmp,  makedumpfile can fail for a little memory in the 2nd
> >                    kernel because makedumpfile makes a very large temporary memory
> >                    bitmap  file in this case. To avoid this failure, you can set a
> >                    TMPDIR environment variable. If you do not set a  TMPDIR  envi-
> >                    ronment variable, makedumpfile uses /tmp directory for a tempo-
> >                    rary bitmap file as a default.
> 
> I do not think it will because we run the second kernel inside the
> initramfs and do not mount any extra disks.  So the only location available
> for the temporary memory bitmap would be memory either tmpfs or something
> else.  Regardless the file ends up in memory.

If a file system for a dump file is on the local system, it is effective that
we specify a directory as TMPDIR in the same file system, isn't it?


Thanks
tachibana

> 
> > 
> > 
> > On the other hand, I'm considering the enhancement suggested by Hatayama-san now.
> 
> His idea looks interesting if it works.  Thanks.
> 
> Cheers,
> Don
> 
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