The patch titled
memory hotplug: fix updating of num_physpages for hot plugged memory
has been added to the -mm tree. Its filename is
memory-hotplug-fix-updating-of-num_physpages-for-hot-plugged-memory.patch
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------------------------------------------------------
Subject: memory hotplug: fix updating of num_physpages for hot plugged memory
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Sizing of memory allocations shouldn't depend on the number of physical
pages found in a system, as that generally includes (perhaps a huge amount
of) non-RAM pages. The amount of what actually is usable as storage
should instead be used as a basis here.
In line with that, the memory hotplug code should update num_physpages in
a way that it retains its original (post-boot) meaning; in particular,
decreasing the value should at best be done with great care - this patch
doesn't try to ever decrease this value at all as it doesn't really seem
meaningful to do so.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
Cc: Badari Pulavarty <pbadari@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff -puN mm/memory_hotplug.c~memory-hotplug-fix-updating-of-num_physpages-for-hot-plugged-memory mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memory-hotplug-fix-updating-of-num_physpages-for-hot-plugged-memory
+++ a/mm/memory_hotplug.c
@@ -339,8 +339,11 @@ EXPORT_SYMBOL_GPL(__remove_pages);
void online_page(struct page *page)
{
+ unsigned long pfn = page_to_pfn(page);
+
totalram_pages++;
- num_physpages++;
+ if (pfn >= num_physpages)
+ num_physpages = pfn + 1;
#ifdef CONFIG_HIGHMEM
if (PageHighMem(page))
@@ -832,7 +835,6 @@ repeat:
zone->present_pages -= offlined_pages;
zone->zone_pgdat->node_present_pages -= offlined_pages;
totalram_pages -= offlined_pages;
- num_physpages -= offlined_pages;
setup_per_zone_wmarks();
calculate_zone_inactive_ratio(zone);
_
Patches currently in -mm which might be from JBeulich@xxxxxxxxxx are
linux-next.patch
memory-hotplug-fix-updating-of-num_physpages-for-hot-plugged-memory.patch
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