Re: [PATCH 0/4] Swap migration V3: Overview

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

mike kravetz wrote:
>>>Just to be clear, there are at least two distinct requirements for hotplug.
>>>One only wants to remove a quantity of memory (location unimportant).  The
>>>other wants to remove a specific section of memory (location specific).  I
>>>think the first is easier to address.
>>>
>>
>>The only difficulty to remove a quantity of memory is how to find
>>where is easy to be removed. If this is fixed, I think it is
>>easier to address.
> 
> 
> We have been using Mel's fragmentation patches.  One of the data structures
> created by these patches is a 'usemap' thats tracks how 'blocks' of memory
> are used.  I exposed the usemaps via sysfs along with other hotplug memory
> section attributes.  So, you can then have a user space program scan the
> usemaps looking for sections that can be easily offlined.
> 
yea, looks nice :)
But such pages are already shown as hotpluggable, I think.
ACPI/SRAT will define the range, in ia64.

The difficulty is how to find hard-to-migrate pages, as Andrew pointed out.



Thanks,
-- Kame

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>