On Wed 19-08-20 12:11:52, David Hildenbrand wrote:
> 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.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
> Cc: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
> Cc: Oscar Salvador <osalvador@xxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> mm/memory_hotplug.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 50aa5df696e9d..098361fcb4504 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1460,10 +1460,10 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
> {
> 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) */
> @@ -1507,7 +1507,6 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
> reason = "failure to isolate range";
> goto failed_removal;
> }
> - nr_isolate_pageblock = ret;
>
> arg.start_pfn = start_pfn;
> arg.nr_pages = nr_pages;
> @@ -1569,7 +1568,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
> * 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 */
> --
> 2.26.2
>
--
Michal Hocko
SUSE Labs
