Re: [PATCH v2] makedumpfile: request the kernel do page scans

Lisa Mitchell
2013-01-16T16:53:34Z

On Wed, 2013-01-16 at 05:15 -0700, Lisa Mitchell wrote:

> Cliff I tried your patch above on makedumpfile v1.5.1 (built dynamically
> on the same DL980 I was running the test on), with all the RHEL 6
> versions of kernel patches you gave me from 1207 plus the kernel patch
> to kexec recommended for makedumpfile v1.5.1 built on top of a
> preliminary RHEL 6.4 kernel source (higher patch level of 2.6.32
> kernel), this time on a 1 TB Memory system (We have lost access to a 4
> TB Memory system for some time, now). On this same system, regular
> Makedumpfile v1.5.1 worked fine to produce a dump. But the Makedumpfile
> with the patches above could not even start the dump, and printed:
>
> Saving vmcore-dmesg.txt
> Saved vmcore-dmesg.txt
> PL_REQUEST_MEMMAP returned -1
> Restarting system.
>
> This happened with both a crashkernel size=200M that would have invoked
> cyclic buffer mode, and also with a larger one, 384M that should not
> have needed cyclic mode. I had no cyclic buffer mode set or turned off
> in the makedumpfile command line, just recording memory usage with:
>
> core_collector makedumpfile -c --message-level 31 -d 31
> debug_mem_level 2
>
>

I got a slightly different error message when I tried the test again on
the same system, setting crashkernel=512M, and adding --non-cyclic to
the makedumpfile command line. It was:

Saving vmcore-dmesg.txt
Saved vmcore-dmesg.txt
Checking for memory holes : [100 %]
PL_REQUEST_MEMMAP returned -1
create_2nd_bitmap: Can't exclude unnecessary pages.