Re: [PATCH v21 5/5] docs: kdump: Update the crashkernel description for arm64

Baoquan He
2022-03-15T11:59:49Z

On 02/27/22 at 11:07am, Zhen Lei wrote:
> Now arm64 has added support for "crashkernel=X,high" and
> "crashkernel=Y,low", and implements "crashkernel=X[@offset]" in the
> same way as x86. So update the Documentation.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

Looks good to me, thx.

Acked-by: Baoquan He <bhe@redhat.com>

> ---
> Documentation/admin-guide/kernel-parameters.txt | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index f5a27f067db9ed9..63098786c93828c 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -789,7 +789,7 @@
> memory region [offset, offset + size] for that kernel
> image. If '@offset' is omitted, then a suitable offset
> is selected automatically.
> - [KNL, X86-64] Select a region under 4G first, and
> + [KNL, X86-64, ARM64] Select a region under 4G first, and
> fall back to reserve region above 4G when '@offset'
> hasn't been specified.
> See Documentation/admin-guide/kdump/kdump.rst for further details.
> @@ -802,20 +802,20 @@
> Documentation/admin-guide/kdump/kdump.rst for an example.
>
> crashkernel=size[KMG],high
> - [KNL, X86-64] range could be above 4G. Allow kernel
> + [KNL, X86-64, ARM64] 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=size[KMG],low
> - [KNL, X86-64] range under 4G. When crashkernel=X,high
> + [KNL, X86-64, ARM64] range under 4G. When crashkernel=X,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, also enough extra
> low memory is needed to make sure DMA buffers for 32-bit
> - devices won't run out. Kernel would try to allocate at
> + devices won't run out. Kernel would try to allocate
> at least 256M below 4G automatically.
> This one let user to specify own low range under 4G
> for second kernel instead.
> --
> 2.25.1
>