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SubjectRe: [POC] Extend "movable_node" to "movable_node=" and add the interface in /sys to show the value
On Wed, Oct 11, 2017 at 04:42:15PM +0800, Baoquan He wrote:
>Hi dear Fan San,
Hi dear Uncle Bao,

>
>On 10/11/17 at 04:23pm, Chao Fan wrote:
>> On Wed, Oct 11, 2017 at 03:55:13PM +0800, Baoquan He wrote:
>> >Hi Fan San,
>> >> 1. Get and parse the srat table before kernel extracted, then mark the memory
>> >> region in movable node which should be avoided in kaslr.
>> >> I have send the patch:
>> >> https://www.spinics.net/lists/kernel/msg2595546.html
>> >> But the change is large and then here is the second method.
>> >>
>> >> 2. Extend the movable_node to movable_node=nn@ss, in which nn means
>> >> the size of memory in immovable node, and ss means the start position of
>> >> this memory region.
>> >> But it brings another question, it may be a little difficult for a normal
>> >> user to specify the nn and ss. Because it's hard for a user to know the value
>> >> of the memory in immovable node.
>> >> So I wonder if it's good to add a interface in /sys, like:
>> >> # cat /sys/device/system/memory/immovable_node
>> >
>> Hi Baoquan,
>>
>> Thanks for your reply,
>>
>> >You can post patch. By the way, can the existing
>> >/sys/devices/system/memory/memoryX/removable be used instead?
>>
>> I ever search the interfaces of /sys/devices/system/memory/, and noticed
>> this "removable", it does be able to help us judge it's removable or not.
>> But we should also get the information of the memory length and start position
>> by other interface. If there is a interface that show the nn and ss, we
>> can use them and change grub directly.
>> And there are more "memoryX" in one node. In my machine, I can see
>> memory0(linked to /sys/devices/system/memory/memory0) - memory7 in
>> /sys/devices/system/node/node0. And total memory38 for 4 nodes. I think
>> it's a little heavy to handle every memoryX.
>> But in SRAT table, one node has one or two memory regions. So I thinks
>> it's more straight and easy to use. How do you think about it?
>
>I am fine, I just mention it.

OK, I just explain I did not find the suitable existing interface.

>
>Then please show your code envelopped in well formatted patch.

OK, will try to make it.

Thanks,
Chao Fan
>
>Thanks
>Baoquan
>
>> >
>> >> nn@ss
>> >> nn@ss
>> >> ...
>> >> to show the two value.
>> >> When srat table is parsed in acpi_parse_memory_affinity, fill the value
>> >> and user can get and use them.
>> >>
>> >> If anyone has a better method, please let me know.
>> >> Any comments will be welcome.
>> >>
>> >> Thanks,
>> >> Chao Fan
>> >>
>> >>
>> >
>> >
>>
>>
>
>


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