From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/memory_hotplug: drop PageReserved() check in online_pages_range() move_pfn_range_to_zone() will set all pages to PG_reserved via memmap_init_zone(). The only way a page could no longer be reserved would be if a MEM_GOING_ONLINE notifier would clear PG_reserved - which is not done (the online_page callback is used for that purpose by e.g., Hyper-V instead). walk_system_ram_range() will never call online_pages_range() with duplicate PFNs, so drop the PageReserved() check. This seems to be a leftover from ancient times where the memmap was initialized when adding memory and we wanted to check for already onlined memory. Link: http://lkml.kernel.org/r/20190814154109.3448-3-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Arun KS <arunks@xxxxxxxxxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Nadav Amit <namit@xxxxxxxxxx> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-drop-pagereserved-check-in-online_pages_range +++ a/mm/memory_hotplug.c @@ -653,9 +653,7 @@ static int online_pages_range(unsigned l { unsigned long onlined_pages = *(unsigned long *)arg; - if (PageReserved(pfn_to_page(start_pfn))) - onlined_pages += online_pages_blocks(start_pfn, nr_pages); - + onlined_pages += online_pages_blocks(start_pfn, nr_pages); online_mem_sections(start_pfn, start_pfn + nr_pages); *(unsigned long *)arg = onlined_pages; _
