[PATCH 04/11] introduce crashkernel option to kdump.conf

[Coiby Xu]

Currently, kexec-tools compares the value of kernel cmdline parameter
crashkernel with default value string "1G-4G:192M,4G-64G:256M,64G-:512M"
to tell if the user wants kexec-tools to automatically manage the value
of crashkernel. Since extra memory needs to be allocated for cases like
swiotlb memory requirement, this comparison would become invalid.
kexec-tools needs the user to explicitly tell kexec-tools if crashkernel
should be managed automatically. Thus introduce crashkernel in
kdump.conf.

Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
 kdump.conf   | 6 ++++++
 kdump.conf.5 | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/kdump.conf b/kdump.conf
index dea2e94..139ed81 100644
--- a/kdump.conf
+++ b/kdump.conf
@@ -11,6 +11,11 @@
 #
 # Supported options:
 #
+# crashkernel <auto|ANY_FORMAT_SUPPORTED_BY_KERNEL_CRASHKERNEL_CMDLINE>
+#           - when crashkernel=auto, kexec-tools will set up the kernel
+#             crashkernel cmdline automatically. Note this is a best-effort
+#             etimation.
+#
 # raw <partition>
 #           - Will dd /proc/vmcore into <partition>.
 #             Use persistent device names for partition devices,
@@ -170,6 +175,7 @@
 #ssh user(a)my.server.com
 #ssh user@2001:db8::1:2:3:4
 #sshkey /root/.ssh/kdump_id_rsa
+crashkernel auto
 path /var/crash
 core_collector makedumpfile -l --message-level 7 -d 31
 #core_collector scp
diff --git a/kdump.conf.5 b/kdump.conf.5
index 6e6cafa..98c16f8 100644
--- a/kdump.conf.5
+++ b/kdump.conf.5
@@ -26,6 +26,13 @@ understand how this configuration file affects the behavior of kdump.
 
 .SH OPTIONS
 
+.B crashkernel <auto|ANY_FORMAT_SUPPORTED_BY_KERNEL_CRASHKERNEL_CMDLINE>
+.RS
+when crashkernel=auto, kexec-tools will set up the kernel crashkernel cmdline
+automatically when installing a kernel. Note the value is based on prior
+experence and doesn't gurantee the resered memory is sufficient for kdump.
+If OOM occurs, please set it to a different value.
+
 .B raw <partition>
 .RS
 Will dd /proc/vmcore into <partition>.  Use persistent device names for
-- 
2.31.1