Re: [PATCH v24 6/6] docs: kdump: Update the crashkernel description for arm64

From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Baoquan He <bhe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	<x86@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
	<linux-kernel@vger.kernel.org>, Dave Young <dyoung@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	Eric Biederman <ebiederm@xmission.com>,
	<kexec@lists.infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	<devicetree@vger.kernel.org>, "Jonathan Corbet" <corbet@lwn.net>,
	<linux-doc@vger.kernel.org>, Randy Dunlap <rdunlap@infradead.org>,
	Feng Zhou <zhoufeng.zf@bytedance.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	Chen Zhou <dingguo.cz@antgroup.com>,
	"John Donnelly" <John.p.donnelly@oracle.com>,
	Dave Kleikamp <dave.kleikamp@oracle.com>
Subject: Re: [PATCH v24 6/6] docs: kdump: Update the crashkernel description for arm64
Date: Sat, 7 May 2022 09:41:00 +0800	[thread overview]
Message-ID: <6e662eae-e788-13d3-368a-e88ed159fc85@huawei.com> (raw)
In-Reply-To: <20220506231451.GB122876@MiWiFi-R3L-srv>

On 2022/5/7 7:14, Baoquan He wrote:
> On 05/06/22 at 07:44pm, Zhen Lei wrote:
>> Now arm64 has added support for "crashkernel=X,high" and
>> "crashkernel=Y,low". Unlike x86, crash low memory is not allocated if
>> "crashkernel=Y,low" is not specified.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>>  Documentation/admin-guide/kernel-parameters.txt | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 3f1cc5e317ed4a5..aa44c61114aa4b8 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -808,7 +808,7 @@
>>  			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
>> @@ -821,7 +821,7 @@
>>  			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.
>> @@ -829,6 +829,11 @@
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>>  
>> +			[KNL, ARM64] range in low memory.
>> +			This one let user to specify a low range in DMA zone for
>                                           ^ not needed,
>                         Maybe Catalin can fix it when merging.

Delete "This one let user to" or the entire sentence? I understand it to be the former.

> 
> Other than this, LGTM,
> 
> Acked-by: Baoquan He <bhe@redhat.com>
> 
>> +			crash dump kernel.
>> +			It will be ignored when crashkernel=X,high is not used.
>> +
>>  	cryptomgr.notests
>>  			[KNL] Disable crypto self-tests
>>  
>> -- 
>> 2.25.1
>>
> 
> .
> 

-- 
Regards,
  Zhen Lei

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