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Commit fb391599 authored by Bernhard Walle's avatar Bernhard Walle Committed by Linus Torvalds
Browse files

Add documentation for extended crashkernel syntax 



This adds the documentation for the extended crashkernel syntax into
Documentation/kdump/kdump.txt.

Signed-off-by: default avatarBernhard Walle <bwalle@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7d7712a3

Documentation/kdump/kdump.txt

+26 −0
Original line number Diff line number Diff line
@@ -231,6 +231,32 @@ Dump-capture kernel config options (Arch Dependent, ia64) 
  any space below the alignment point will be wasted.





Extended crashkernel syntax

===========================



While the "crashkernel=size[@offset]" syntax is sufficient for most

configurations, sometimes it's handy to have the reserved memory dependent

on the value of System RAM -- that's mostly for distributors that pre-setup

the kernel command line to avoid a unbootable system after some memory has

been removed from the machine.



The syntax is:



    crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset]

    range=start-[end]



For example:



    crashkernel=512M-2G:64M,2G-:128M



This would mean:



    1) if the RAM is smaller than 512M, then don't reserve anything

       (this is the "rescue" case)

    2) if the RAM size is between 512M and 2G, then reserve 64M

    3) if the RAM size is larger than 2G, then reserve 128M





Boot into System Kernel

=======================

Documentation/kernel-parameters.txt

+7 −0
Original line number Diff line number Diff line
@@ -497,6 +497,13 @@ and is between 256 and 4096 characters. It is defined in the file 
			[KNL] Reserve a chunk of physical memory to

			hold a kernel to switch to with kexec on panic.



	crashkernel=range1:size1[,range2:size2,...][@offset]

			[KNL] Same as above, but depends on the memory

			in the running system. The syntax of range is

			start-[end] where start and end are both

			a memory unit (amount[KMG]). See also

			Documentation/kdump/kdump.txt for a example.



	cs4232=		[HW,OSS]

			Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>