Messages in this thread Patch in this message | | | Date | Tue, 18 Aug 2009 16:33:41 +0100 | From | "Jan Beulich" <> | Subject | [PATCH] fix updating of num_physpages for hot plugged memory |
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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@novell.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
--- mm/memory_hotplug.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- linux-2.6.31-rc6/mm/memory_hotplug.c 2009-08-18 15:31:56.000000000 +0200 +++ 2.6.31-rc6-use-totalram_pages/mm/memory_hotplug.c 2009-08-17 15:21:19.000000000 +0200 @@ -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)) @@ -831,7 +834,6 @@ 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);
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