From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/memory_hotplug: drop nr_isolate_pageblock in offline_pages() We make sure that we cannot have any memory holes right at the beginning of offline_pages() and we only support to online/offline full sections. Both, sections and pageblocks are a power of two in size, and sections always span full pageblocks. We can directly calculate the number of isolated pageblocks from nr_pages. Link: https://lkml.kernel.org/r/20200819175957.28465-6-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx> Cc: Charan Teja Reddy <charante@xxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx> Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-drop-nr_isolate_pageblock-in-offline_pages +++ a/mm/memory_hotplug.c @@ -1471,10 +1471,10 @@ int __ref offline_pages(unsigned long st { const unsigned long end_pfn = start_pfn + nr_pages; unsigned long pfn, system_ram_pages = 0; - int ret, node, nr_isolate_pageblock; unsigned long flags; struct zone *zone; struct memory_notify arg; + int ret, node; char *reason; /* We can only offline full sections (e.g., SECTION_IS_ONLINE) */ @@ -1518,7 +1518,6 @@ int __ref offline_pages(unsigned long st reason = "failure to isolate range"; goto failed_removal; } - nr_isolate_pageblock = ret; arg.start_pfn = start_pfn; arg.nr_pages = nr_pages; @@ -1596,7 +1595,7 @@ int __ref offline_pages(unsigned long st * pageblocks zone counter here. */ spin_lock_irqsave(&zone->lock, flags); - zone->nr_isolate_pageblock -= nr_isolate_pageblock; + zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; spin_unlock_irqrestore(&zone->lock, flags); /* removal success */ _
