Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19

Kamezawa Hiroyuki
2005-11-01T16:59:18Z

Kamezawa Hiroyuki wrote:
> Ingo Molnar wrote:
>
>> so it's all about expectations: _could_ you reasonably remove a piece
>> of RAM? Customer will say: "I have stopped all nonessential services,
>> and free RAM is at 90%, still I cannot remove that piece of faulty
>> RAM, fix the kernel!". No reasonable customer will say: "True, I have
>> all RAM used up in mlock()ed sections, but i want to remove some RAM
>> nevertheless".
>>
> Hi, I'm one of men in -lhms
>
> In my understanding...
> - Memory Hotremove on IBM's LPAR? approach is
> [remove some amount of memory from somewhere.]
> For this approach, Mel's patch will work well.
> But this will not guaranntee a user can remove specified range of
> memory at any time because how memory range is used is not defined by
> an admin
> but by the kernel automatically. But to extract some amount of memory,
> Mel's patch is very important and they need this.
>
One more consideration...
Some cpus which support virtialization will be shipped by some vendor in near future.
If someone uses vitualized OS, only problem is *resizing*.
Hypervisor will be able to remap semi-physical pages anyware with hardware assistance
but system resizing needs operating system assistance.
To this direction, [remove some amount of memory from somewhere.] is important approach.

-- Kame