On Wed 19-08-20 12:11:51, David Hildenbrand wrote:
> offline_pages() is the only user. __offline_isolated_pages() never gets
> called with ranges that contain memory holes and we no longer care about
> the return value. Drop the return value handling and all pfn_valid()
> checks.
>
> Update the documentation.
>
> 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>
> ---
> include/linux/memory_hotplug.h | 4 ++--
> mm/page_alloc.c | 27 ++++-----------------------
> 2 files changed, 6 insertions(+), 25 deletions(-)
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 375515803cd83..0b461691d1a49 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -103,8 +103,8 @@ extern int online_pages(unsigned long pfn, unsigned long nr_pages,
> int online_type, int nid);
> extern struct zone *test_pages_in_a_zone(unsigned long start_pfn,
> unsigned long end_pfn);
> -extern unsigned long __offline_isolated_pages(unsigned long start_pfn,
> - unsigned long end_pfn);
> +extern void __offline_isolated_pages(unsigned long start_pfn,
> + unsigned long end_pfn);
>
> typedef void (*online_page_callback_t)(struct page *page, unsigned int order);
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index cf0b25161feae..03f585f95dc60 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -8692,35 +8692,21 @@ void zone_pcp_reset(struct zone *zone)
>
> #ifdef CONFIG_MEMORY_HOTREMOVE
> /*
> - * All pages in the range must be in a single zone and isolated
> - * before calling this.
> + * All pages in the range must be in a single zone, must not contain holes,
> + * must span full sections, and must be isolated before calling this function.
> */
> -unsigned long
> -__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> +void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> {
> + unsigned long pfn = start_pfn;
> struct page *page;
> struct zone *zone;
> unsigned int order;
> - unsigned long pfn;
> unsigned long flags;
> - unsigned long offlined_pages = 0;
> -
> - /* find the first valid pfn */
> - for (pfn = start_pfn; pfn < end_pfn; pfn++)
> - if (pfn_valid(pfn))
> - break;
> - if (pfn == end_pfn)
> - return offlined_pages;
>
> offline_mem_sections(pfn, end_pfn);
> zone = page_zone(pfn_to_page(pfn));
> spin_lock_irqsave(&zone->lock, flags);
> - pfn = start_pfn;
> while (pfn < end_pfn) {
> - if (!pfn_valid(pfn)) {
> - pfn++;
> - continue;
> - }
> page = pfn_to_page(pfn);
> /*
> * The HWPoisoned page may be not in buddy system, and
> @@ -8728,7 +8714,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> */
> if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
> pfn++;
> - offlined_pages++;
> continue;
> }
> /*
> @@ -8739,20 +8724,16 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
> BUG_ON(page_count(page));
> BUG_ON(PageBuddy(page));
> pfn++;
> - offlined_pages++;
> continue;
> }
>
> BUG_ON(page_count(page));
> BUG_ON(!PageBuddy(page));
> order = page_order(page);
> - offlined_pages += 1 << order;
> del_page_from_free_list(page, zone, order);
> pfn += (1 << order);
> }
> spin_unlock_irqrestore(&zone->lock, flags);
> -
> - return offlined_pages;
> }
> #endif
>
> --
> 2.26.2
>
--
Michal Hocko
SUSE Labs
