From fb391599f2eaf22197e3e914187c957ef7eeb4c5 Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Thu, 18 Oct 2007 23:41:02 -0700 Subject: [PATCH] Add documentation for extended crashkernel syntax This adds the documentation for the extended crashkernel syntax into Documentation/kdump/kdump.txt. Signed-off-by: Bernhard Walle Cc: Andi Kleen Cc: "Luck, Tony" Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Paul Mundt Cc: Vivek Goyal Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/kdump/kdump.txt | 26 ++++++++++++++++++++++++++ Documentation/kernel-parameters.txt | 7 +++++++ 2 files changed, 33 insertions(+) diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 1b37b28cc2..d0ac72cc19 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -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=:[,:,...][@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 ======================= diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 189df0bcab..0a3fed4452 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -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: ,,,,, -- 2.39.5