Messages in this thread Patch in this message | | | Date | Tue, 23 May 2006 17:29:32 +0900 | From | Yasunori Goto <> | Subject | [Patch]Fix spanned_pages is not updated at a case of memory hot-add. |
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Hello.
I found there is a bug in grow_zone_span() and grow_pgdat_span().
Please apply.
--------- If hot-added memory's address is smaller than old area, spanned_pages will not be updated. It must be fixed.
example) Old zone_start_pfn = 0x60000, and spanned_pages = 0x10000 Added new memory's start_pfn = 0x50000, and end_pfn = 0x60000
new spanned_pages will be still 0x10000 by old code. (It should be updated to 0x20000.) Because old_zone_end_pfn will be 0x70000, and end_pfn smaller than it. So, spanned_pages will not be updated. In current code, spanned_pages is updated only when end_pfn is updated. But, it should be updated even if end_pfn is not updated, because start_pfn might be changed.
This is for 2.6.17-rc4-mm3. I tested this patch on Tiger4 with my node emulation.
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
------------------------------------------------
mm/memory_hotplug.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-)
Index: pgdat15/mm/memory_hotplug.c =================================================================== --- pgdat15.orig/mm/memory_hotplug.c 2006-05-23 14:58:21.000000000 +0900 +++ pgdat15/mm/memory_hotplug.c 2006-05-23 14:58:29.000000000 +0900 @@ -95,16 +95,18 @@ EXPORT_SYMBOL_GPL(__add_pages); static void grow_zone_span(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { - unsigned long old_zone_end_pfn; + unsigned long new_zone_end_pfn; zone_span_writelock(zone); - old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; + new_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; if (start_pfn < zone->zone_start_pfn) zone->zone_start_pfn = start_pfn; - if (end_pfn > old_zone_end_pfn) - zone->spanned_pages = end_pfn - zone->zone_start_pfn; + if (end_pfn > new_zone_end_pfn) + new_zone_end_pfn = end_pfn; + + zone->spanned_pages = new_zone_end_pfn - zone->zone_start_pfn; zone_span_writeunlock(zone); } @@ -112,14 +114,16 @@ static void grow_zone_span(struct zone * static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, unsigned long end_pfn) { - unsigned long old_pgdat_end_pfn = + unsigned long new_pgdat_end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages; if (start_pfn < pgdat->node_start_pfn) pgdat->node_start_pfn = start_pfn; - if (end_pfn > old_pgdat_end_pfn) - pgdat->node_spanned_pages = end_pfn - pgdat->node_start_pfn; + if (end_pfn > new_pgdat_end_pfn) + new_pgdat_end_pfn = end_pfn; + + pgdat->node_spanned_pages = new_pgdat_end_pfn - pgdat->node_start_pfn; } int online_pages(unsigned long pfn, unsigned long nr_pages) -- Yasunori Goto
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