mm, memory_hotplug: cleanup memory offline path
check_pages_isolated_cb currently accounts the whole pfn range as being
offlined if test_pages_isolated suceeds on the range. This is based on
the assumption that all pages in the range are freed which is currently
the case in most cases but it won't be with later changes, as pages marked
as vmemmap won't be isolated.
Move the offlined pages counting to offline_isolated_pages_cb and rely on
__offline_isolated_pages to return the correct value.
check_pages_isolated_cb will still do it's primary job and check the pfn
range.
While we are at it remove check_pages_isolated and offline_isolated_pages
and use directly walk_system_ram_range as do in online_pages.
Link: http://lkml.kernel.org/r/20190408082633.2864-2-osalvador@suse.de
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 96ca656..c45da9f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8453,7 +8453,7 @@ void zone_pcp_reset(struct zone *zone)
* All pages in the range must be in a single zone and isolated
* before calling this.
*/
-void
+unsigned long
__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
{
struct page *page;
@@ -8461,12 +8461,15 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
unsigned int order, i;
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;
+ return offlined_pages;
+
offline_mem_sections(pfn, end_pfn);
zone = page_zone(pfn_to_page(pfn));
spin_lock_irqsave(&zone->lock, flags);
@@ -8484,12 +8487,14 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
pfn++;
SetPageReserved(page);
+ offlined_pages++;
continue;
}
BUG_ON(page_count(page));
BUG_ON(!PageBuddy(page));
order = page_order(page);
+ offlined_pages += 1 << order;
#ifdef CONFIG_DEBUG_VM
pr_info("remove from free list %lx %d %lx\n",
pfn, 1 << order, end_pfn);
@@ -8502,6 +8507,8 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
pfn += (1 << order);
}
spin_unlock_irqrestore(&zone->lock, flags);
+
+ return offlined_pages;
}
#endif