[RFC] pearing off zone from physical memory layout [0/10]

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

Hi,

This series of patches remove members from zone, which depends on physical
memory layout, zone_start_pfn, spanned_pages, zone_mem_map against 2.6.16-rc1.

By this, zone's meaning will be changed from "a range of memory to be used
in a same manner" to "a group of memory to be used in a same manner".

Now, the kernel and memmap became sparse if SPARSEMEM=y,  but zone is considered
as a range of memory.

memory-hot-add adds memory to HIGHMEM, but a zone is considered as a range.
This means memory layout (after hot add) like this is ok,
NORMAL | NORMAL  | HIGHMEM | HIGHMEM.
but this is insane
NORMAL | HIGHMEM | NORMAL  | HIGHMEM. (we can do, but insane)

IMHO, a zone is  an unit of allocation/reclaim of same type of pages.
I think that a zone should be defined by its usage/purpose not by physical
memory layout.

Some codes which wants to walk through all pages in a zone is supported by
for_each_page_in_zone() macro.

I tested this on my desktop machine a little, but  I know this patch needs
more work on some arch (ia64 etc...).

comments ?


-- 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>