path: root/Documentation
diff options
authorYinghai Lu <yinghai@kernel.org>2013-04-15 22:23:47 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2013-04-17 12:35:33 -0700
commit55a20ee7804ab64ac90bcdd4e2868a42829e2784 (patch)
treeae8701054b3da8ac5d46d1cbdbb9c67a5ebd0591 /Documentation
parentc729de8fcea37a1c444e81857eace12494c804a9 (diff)
x86, kdump: Retore crashkernel= to allocate under 896M
Vivek found old kexec-tools does not work new kernel anymore. So change back crashkernel= back to old behavoir, and add crashkernel_high= to let user decide if buffer could be above 4G, and also new kexec-tools will be needed. -v2: let crashkernel=X override crashkernel_high= update description about _high will be ignored by crashkernel=X -v3: update description about kernel-parameters.txt according to Vivek. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1366089828-19692-4-git-send-email-yinghai@kernel.org Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'Documentation')
1 files changed, 11 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cff672da248..709eb3edc6b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -603,9 +603,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for an example.
+ crashkernel_high=size[KMG]
+ [KNL, x86_64] range could be above 4G. Allow kernel
+ to allocate physical memory region from top, so could
+ be above 4G if system have more than 4G ram installed.
+ Otherwise memory region will be allocated below 4G, if
+ available.
+ It will be ignored if crashkernel=X is specified.
- [KNL, x86_64] range under 4G. When crashkernel= is
- passed, kernel allocate physical memory region
+ [KNL, x86_64] range under 4G. When crashkernel_high= is
+ passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
requires at least 64M+32K low memory. Kernel would
@@ -613,6 +620,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
This one let user to specify own low range under 4G
for second kernel instead.
0: to disable low allocation.
+ It will be ignored when crashkernel_high=X is not used
+ or memory reserved is below 4G.
cs89x0_dma= [HW,NET]
Format: <dma>