Re: [RFC][PATCH 0/2] Export memblock migrate type to /sysfs

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Wed, 24 Oct 2007 09:37:40 -0700
Badari Pulavarty <pbadari@us.ibm.com> wrote:

> Hi,
> 
> Now that grouping of pages by mobility is in mainline, I would like 
> to make use of it for selection memory blocks for hotplug memory remove.
> Following set of patches exports memblock's migrate type to /sysfs. 
> This would be useful for user-level agent for selecting memory blocks
> to try to remove.
> 
> 	[PATCH 1/2] Fix migratetype_names[] and make it available
> 	[PATCH 2/2] Add mem_type in /syfs to show memblock migrate type
> 
At first, I welcome this patch. Thanks :)
> Todo:
> 
> 	Currently, we decide the memblock's migrate type looking at
> first page of memblock. But on some architectures (x86_64), each
> memblock can contain multiple groupings of pages by mobility. Is it
> important to address ?

Hmm, that is a problem annoying me. There is 2 points.

1. In such arch, we'll have to use ZONE_MOVABLE for hot-removable.
2. But from view of showing information to users, more precice is better
   of course.

How about showing information as following ?
==
%cat ./memory/memory0/mem_type
 1 0 0 0 0
%
as 
 Reserved Unmovable Movable Reserve Isolate

==
This is not difficult and can show all information.

Thanks,
-Kame

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