From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/memory_hotplug: simplify online_pages_range() online_pages always corresponds to nr_pages. Simplify the code, getting rid of online_pages_blocks(). Add some comments. Link: http://lkml.kernel.org/r/20190814154109.3448-4-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 | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-simplify-online_pages_range +++ a/mm/memory_hotplug.c @@ -632,31 +632,27 @@ static void generic_online_page(struct p #endif } -static int online_pages_blocks(unsigned long start, unsigned long nr_pages) -{ - unsigned long end = start + nr_pages; - int order, onlined_pages = 0; - - while (start < end) { - order = min(MAX_ORDER - 1, - get_order(PFN_PHYS(end) - PFN_PHYS(start))); - (*online_page_callback)(pfn_to_page(start), order); - - onlined_pages += (1UL << order); - start += (1UL << order); - } - return onlined_pages; -} - static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { - unsigned long onlined_pages = *(unsigned long *)arg; + const unsigned long end_pfn = start_pfn + nr_pages; + unsigned long pfn; + int order; + + /* + * Online the pages. The callback might decide to keep some pages + * PG_reserved (to add them to the buddy later), but we still account + * them as being online/belonging to this zone ("present"). + */ + for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) { + order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn))); + (*online_page_callback)(pfn_to_page(pfn), order); + } - onlined_pages += online_pages_blocks(start_pfn, nr_pages); - online_mem_sections(start_pfn, start_pfn + nr_pages); + /* mark all involved sections as online */ + online_mem_sections(start_pfn, end_pfn); - *(unsigned long *)arg = onlined_pages; + *(unsigned long *)arg += nr_pages; return 0; } _
