Messages in this thread Patch in this message | | | Date | Fri, 21 Aug 2009 02:55:34 -0400 | From | Amerigo Wang <> | Subject | [Patch 8/8] doc: update the kdump document |
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Update the document for kdump.
Signed-off-by: WANG Cong <amwang@redhat.com>
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Index: linux-2.6/Documentation/kdump/kdump.txt =================================================================== --- linux-2.6.orig/Documentation/kdump/kdump.txt +++ linux-2.6/Documentation/kdump/kdump.txt @@ -147,6 +147,15 @@ System kernel config options analysis tools require a vmlinux with debug symbols in order to read and analyze a dump file. +4) Enable "automatically reserve memory for kexec kernel" in + "Processor type and features." + + CONFIG_KEXEC_AUTO_RESERVE=y + + This will let you to use "crashkernel=auto", instead of specifying + numbers for "crashkernel=". Note, you need to have enough memory. + The threshold and reserved memory size are arch-dependent. + Dump-capture kernel config options (Arch Independent) ----------------------------------------------------- @@ -266,6 +275,25 @@ This would mean: 2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M 3) if the RAM size is larger than 2G, then reserve 128M +Or you can use: + + crashkernel=auto + +if you have enough memory. The threshold is 4G, below which this won't work. + +The automatically reserved memory size would be 128M on x86_32, 256M on +ppc, 1/32 of your physical memory size on x86_64 and ppc64 (but it will not +exceed 1TB/32 if you have more). IA64 has its own policy, shown below: + + Memory size Reserved memory + =========== =============== + [4G, 12G) 256M + [12G, 128G) 512M + [128G, 256G) 768M + [256G, 378G) 1024M + [378G, 512G) 1536M + [512G, 768G) 2048M + [768G, ) 3072M Boot into System Kernel
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