RE: [PATCH] crash dump: don't delete non-E820_RAM during init

[Zhang, Jun]

Hello, Anvin
1) use "memmap=exactmap", which remove all ranges include ram and non-ram range. So my first patch reserve the non-ram range.
2)don't use " memmap=exactmap ", so it reserve all ranges. But we only need non-ram, so we need kernel to remove RAM, just as my second patch.


Best Regards!

Jun Zhang
Inet: 8821-4273
Dir.Tel: 86-21-6116-4273
Email: jun.zhang@xxxxxxxxx


-----Original Message-----
From: H. Peter Anvin [mailto:hpa@xxxxxxxxx] 
Sent: Monday, November 05, 2012 10:39 AM
To: Zhang, Jun
Cc: Thomas Gleixner; Ingo Molnar; x86@xxxxxxxxxx; Andrew Morton; Fleming, Matt; Paul Gortmaker; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] crash dump: don't delete non-E820_RAM during init

On 11/05/2012 02:37 AM, Zhang, Jun wrote:
> Hello, Gortmaker
> I will modify my subject. Thanks!
> 
> Hello, Anvin
> from our three options, I think third option is better. But in 3) option, there are two choose, 3.1) is like memmap=REMOVERAM, 3.2) is memmap=CRASHKDUMP.
> In 3.1) we maybe need ifdef/endif within the { } of the function (like exactmap).
> In 3.2) we can remove the ifdef/endif. 
> Which one is the better? Maybe you have a better solution, please share it. 
> Thanks!
> 
> Next is our three option.
> 1)  my patch.
> 2)  modify kexec, only pass two parameters -- memmap=544K@64K 
>     memmap=64964K@32768K, in kernel setup_memory_map, we can remove RAM 
>     range.
> 3)  add extra optional, 3.1) like memmap=REMOVERAM
>                    3.2) like memmap=CRASHKDUMP
> 

Again, 2 would be better because it is a localized change to kexec.  If that works I don't see why there is any reason to change anything else.

	-hpa


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