Re: [PATCH v7 0/4] support reserving crashkernel above 4G on arm64 kdump

[John Donnelly <john.p.donnelly@oracle.com>]

> On May 19, 2020, at 5:21 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> 
> On Thu, Mar 26, 2020 at 4:10 AM Chen Zhou <chenzhou10@huawei.com> wrote:
>> 
>> Hi all,
>> 
>> Friendly ping...
> 
> I was asked about this patch series, and see that you last posted it in
> December. I think you should rebase it to linux-5.7-rc6 and post the
> entire series again to make progress, as it's unlikely that any maintainer
> would pick up the patches from last year.
> 
> For the contents, everything seems reasonable to me, but I noticed that
> you are adding a property to the /chosen node without adding the
> corresponding documentation to
> Documentation/devicetree/bindings/chosen.txt
> 
> Please add that, and Cc the devicetree maintainers on the updated
> patch.
> 
>         Arnd
> 
>> On 2019/12/23 23:23, Chen Zhou wrote:
>>> This patch series enable reserving crashkernel above 4G in arm64.
>>> 
>>> There are following issues in arm64 kdump:
>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>>> when there is no enough low memory.
>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>>> will boot failure because there is no low memory available for allocation.
>>> 
>>> The previous changes and discussions can be retrieved from:
>>> 
>>> Changes since [v6]
>>> - Fix build errors reported by kbuild test robot.
> ...


 Hi 

We found 

https://lkml.org/lkml/2020/4/30/1583

Has cured our Out-Of-Memory kdump failures. 

From	Henry Willard 
Subject	[PATCH] mm: Limit boost_watermark on small zones.

I am currently not on linux-kernel@vger.kernel.org. dlist for all to see  this message so you may want to rebase and see if this cures your OoM issue and share the results.