Re: [RESEND PATCH] kexec : add sparse memory related values to vmcore

From: Liu hua <sdu.liu@huawei.com>
To: Simon Horman <horms@verge.net.au>
Cc: wangnan0@huawei.com, peifeiyue@huawei.com, liusdu@126.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	hui.geng@huawei.com, kumagai-atsushi@mxc.nes.nec.co.jp,
	ebiederm@xmission.com, anderson@redhat.com
Subject: Re: [RESEND PATCH] kexec : add sparse memory related values to vmcore
Date: Tue, 3 Jun 2014 09:26:52 +0800	[thread overview]
Message-ID: <538D245C.5090101@huawei.com> (raw)
In-Reply-To: <20140529001328.GD22705@verge.net.au>

On 2014/5/29 8:13, Simon Horman 写道:
> On Wed, May 28, 2014 at 09:49:56PM +0800, Liu Hua wrote:
>> This patch deales with sparse memory model.
>>
>> For ARM32 platforms, different vendors may define different
>> SECTION_SIZE_BITS, which we did not write to vmcore.
>>
>> For example:
>>
>>   1 arch/arm/mach-clps711x/include/mach/memory.h
>>     #define SECTION_SIZE_BITS 24
>>   2 arch/arm/mach-exynos/include/mach/memory.h
>>     #define SECTION_SIZE_BITS 28
>>   3 arch/arm/mach-sa1100/include/mach/memory.h
>>     #define SECTION_SIZE_BITS 27
> 
> I wonder if this problem will eventually go away, or at least only
> apply to older platforms, as ARM moves towards multiplatform: a single
> kernel for more than one platform.


>> It is really a bad news for user space tools such as
>> makedumpfile and crash, who have to defines them as
>> macros. So for the same architecture, we may need to
>> recomile them to parse vmcores with different
>> SECTION_SIZE_BITS.
>>
>> And if we enable LPAE, MAX_PHYSMEM_SIZE can alse
>> be variable.
>>
>> This patch adds these SECTION_SIZE_BITS and MAX_PHYSMEM_SIZE
>> to vmcore. which makes user space tools more compatible.
>>
>> BTW, makedumpfile has queued the related patch.
>>
>> Signed-off-by: Liu Hua <sdu.liu@huawei.com>
>> ---
>>  kernel/kexec.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/kernel/kexec.c b/kernel/kexec.c
>> index bf0b929e..8b1a193 100644
>> --- a/kernel/kexec.c
>> +++ b/kernel/kexec.c
>> @@ -1577,6 +1577,8 @@ static int __init crash_save_vmcoreinfo_init(void)
>>  	VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
>>  	VMCOREINFO_STRUCT_SIZE(mem_section);
>>  	VMCOREINFO_OFFSET(mem_section, section_mem_map);
>> +	VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
>> +	VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
>>  #endif
>>  	VMCOREINFO_STRUCT_SIZE(page);
>>  	VMCOREINFO_STRUCT_SIZE(pglist_data);
>> -- 
>> 1.9.0
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
>>
> 
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> 
> .
> 


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