[PATCH v3 0/2] arm64: kdump: Function supplement and performance optimization

[Baoquan He]

Hi Catalin,

On 07/11/22 at 05:03pm, Zhen Lei wrote:
> v2 --> v3:
> 1. Discard patch 3 in v2, a cleanup patch.
> 
> v1 --> v2:
> 1. Update the commit message of Patch 1, explicitly indicates that "crashkernel=X,high"
>    is specified but "crashkernel=Y,low" is not specified.
> 2. Drop Patch 4-5. Currently, focus on function integrity, performance optimization
>    will be considered in later versions.
> 3. Patch 3 is not mandatory, it's just a cleanup now, although it is a must for patch 4-5.
>    But to avoid subsequent duplication of effort, I'm glad it was accepted.
> 
> 
> v1:
> After the basic functions of "support reserving crashkernel above 4G on arm64
> kdump"(see https://lkml.org/lkml/2022/5/6/428) are implemented, we still have
> three features to be improved.
> 1. When crashkernel=X,high is specified but crashkernel=Y,low is not specified,
>    the default crash low memory size is provided.
> 2. For crashkernel=X without '@offset', if the low memory fails to be allocated,
>    fall back to reserve region from high memory(above DMA zones).
> 3. If crashkernel=X,high is used, page mapping is performed only for the crash
>    high memory, and block mapping is still used for other linear address spaces.
>    Compared to the previous version:
>    (1) For crashkernel=X[@offset], the memory above 4G is not changed to block
>        mapping, leave it to the next time.
>    (2) The implementation method is modified. Now the implementation is simpler
>        and clearer.

Do you have plan to pick this series so that it can be taken into 5.20
rc-1~3?

We have back ported the basic crashkernel=high, low, support into our
distros and have taken wide testing on arm64 servers, need this patchset
to back port for more testing. 

Thanks
Baoquan

> 
> Zhen Lei (2):
>   arm64: kdump: Provide default size when crashkernel=Y,low is not
>     specified
>   arm64: kdump: Support crashkernel=X fall back to reserve region above
>     DMA zones
> 
>  .../admin-guide/kernel-parameters.txt         | 10 ++-----
>  arch/arm64/mm/init.c                          | 28 +++++++++++++++++--
>  2 files changed, 28 insertions(+), 10 deletions(-)
> 
> -- 
> 2.25.1
>