diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 13 |
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. crashkernel_low=size[KMG] - [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> |