On Wed, Apr 05, 2017 at 05:42:59PM +0200, Michal Hocko wrote:
But one thing that is really bugging me is how could you see low pfns
in the previous oops. Please drop the last patch and sprinkle printks
down the remove_memory path to see where this all go south. I believe
that there is something in the initialization code lurking in my code.
Please also scratch the pfn_valid check in online_pages diff. It will
not help here.
Got it.
shrink_pgdat_span: start_pfn=0x10000, end_pfn=0x10100, pgdat_start_pfn=0x0, pgdat_end_pfn=0x20000
The problem is that pgdat_start_pfn here should be 0x10000. As you
suspected, it never got set. This fixes things for me.
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 623507f..37c1b63 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -884,7 +884,7 @@ static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned lon
{
unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
- if (start_pfn < pgdat->node_start_pfn)
+ if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
pgdat->node_start_pfn = start_pfn;
pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
---
Along these lines, maybe we should also do
- if (start_pfn < zone->zone_start_pfn)
+ if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
in resize_zone_range()?
--
Reza Arbab
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