Re: [RFC][-mm][PATCH 3/6] oom-killer: count lowmem rss

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

Christoph Lameter wrote:
>
> I dont think this patch will work in !NUMA but its useful there too. Can
> you make this work in general?
>
for NUMA
==
+static inline int is_lowmem_page(struct page *page)
+{
+	if (unlikely(page_zonenum(page) < policy_zone))
+		return 1;
+	return 0;
+}
==

is used. Doesn't this work well ?
This check means
It enough memory:
   On my ia64 box ZONE_DMA(<4G), x86-64 box(GFP_DMA32) is caught
If small memory (typically < 4G)
   ia64 box no lowmem, x86-64 box GPF_DMA is caught
If all zones are policy zone (ppc)
   no lowmem zone.

Because "amount of memory" changes the situation "which is lowmem?",
I used policy zone. If this usage is not appropriate, I'll add some new.

BTW, is it better to export this value from somewhere ?

Thanks,
-Kame